Titanium applications in electroplating
Relevance
Thegalvanic method of metal coating is the most widespread. To increase the intensity and efficiency of production and technological processes of electroplating, new electrolytes are used, increasing the temperature and current density. This requires construction materials and equipment that meet the increased requirements of corrosion resistance. In addition to improving technical performance, it is crucial to maximize the service life of the equipment, which depends on the quality of the lining and construction materials. Despite the fact that there are quite a lot of materials for safe operation of equipment, it is still not possible to solve the problems related to durability and longevity. Lead in chromium and other acidic electrolytes, although chemically resistant, is easily destroyed mechanically. If the lead lining gets damaged, the tub body is subjected to intense corrosion.
Alternative materials
Steel baths lined with vinyl plastic which is resistant to acidic electrolytes are used for nickel plating, copper plating, galvanizing
Corrosion resistance of titanium
Of all the materials that exhibit a high level of corrosion resistance in most electrolytes, titanium alloys are considered the most optimal for use. Titanium is known for its resistance to corrosion in virtually all alkaline, weakly acidic and acidic electrolytes. It is resistant in pickling solutions containing 10% H2 SO4 at 75 °C, but when the concentration rises to 18-20%, it begins to corrode quickly. If nitric acid or its salts are added to the electrolyte as inhibiting additives, the corrosive destruction of titanium can be prevented. In this case, an oxide film is formed on the surface of the metal, which prevents its dissolution. Titanium will also corrode rapidly in electrolytes containing hydrofluoric or hydrofluoric acid. In all other cases the use of titanium as a protective coating in electroplating is extremely promising.
Electroplating equipment
For pretreatment and plating, tubs, anode baskets, cathode drums, heating coils, hangers, heat exchangers, pipes, filters, pumps, etc. are used.
Baths
Titanium baths for chromium plating are made of BT1-0 alloy. This technology has been used for a long time by "Kommunar" automobile plant and also by Zaporozhye measuring instrument production plant. The use of titanium in chromium baths increases their service life by five to seven times. When Melitopol engine plant instead of traditional baths of steel and lead were installed three baths of BT1-0 alloy, then due to increasing the duration of theirand reducing depreciation charges, electrolyte costs and reducing labor and energy intensity, it was possible to significantly increase the annual revenue figure.
In electrolytes used in copper plating, nickel plating, cadmium plating, brass plating, galvanizing and silver plating, titanium experiences virtually no corrosive degradation beyond hydrofluoric acid and boronfluoric acid solutions. In addition, it is undesirable to use titanium in combination with media containing fluoride ions because of the difference in corrosion rate when using the anodic circuit and current cutoff.
Replacement of baths made of carbon steel, lined with vinyl plastic or lead, by titanium baths is advisable to stabilize the production process: reducing the frequency of current repairs, maintaining the purity of the electrolyte, increasing the quality of coating, and most importantly - the ability to adjust the temperature or acid balance of the electrolyte. Resistance of titanium alloys to corrosion in the above-mentioned electrolytes makes it possible to reduce the wall thickness by more than half. This makes titanium baths and vinyl lined steel baths virtually identical in cost.
Anode baskets
Three types of anodes are used in baths designed for nickel plating, galvanizing and copper plating: electrolytic, cast and rolled. The latter are most commonly used as they dissolve most uniformly, whereas electrolytic anodes are characterized by more intensive dissolution and sludge formation.
In order to minimize the harmful effects of sludge, the anodes are placed in special "belting" or "chloride" bags which have previously been treated with hydrochloric acid. In this case, the waste reaches only twenty to thirty percent of the total weight of the anodes. The use of anode baskets made of titanium is extremely promising. As early as 1959, Ford developed and put into operation the first anode bins made of titanium. This greatly reduced the maintenance costs of the equipment and increased the daily operating time by four hours.
The anode garbage cans are designed to increase the overall capacity of the operating plant. In addition, it is not necessary to drain the remaining solution from the bath to add anode material to the tank. The anode material is consumed practically in its entirety, maintaining a constant density and ensuring maximum efficiency of its action. Since 1959, they have been used for cyanide and acid copper plating, cyanide white brass plating and bright nickel plating. Introduction of titanium baskets into the domestic production process made it possible to create a fully soluble anode.
VT1-0.
The application of anode baskets made of the BT1-0 titanium alloy at the Melitopol motor works made it possible to raise considerably the annual economic indicator in the production of nickel-plated parts used in power units. The main indicator of economical efficiency of this innovation is the 100% usage of nickel anodes, whereas before the technology implementation only 70% of all anodes were used. Besides, it is no longer necessary to use copper hooks that were previously used for installation of new anodes, and labor costs for anode replacement are reduced.
Zaporozhye plant "Kommunar" managed to get away from the ratio of income and total consumption of nickel anodes that were not used in future, which was 30% at the automatic line of electroplating. Titanium baskets made of BT1-0 alloy made it possible to significantly reduce the consumption of nickel anodes and to simplify bath maintenance while correcting the electrolyte level.
Anode baskets with special hooks for hanging are created from 0.8-1 millimeter thick titanium sheets. The cross section of the hooks is calculated on the basis of low heat capacity and current density, which is less than 1A/dm.
Bowing
For the high-speed tinning process, titanium baskets are used, which are pre-filled with granulated tin acting as an anode. This anode material significantly increases the productivity of electrolytic tinning by increasing the active current density which is distributed over the whole area of the anode in the basket.
Economic effect
The titanium baskets designed according to different schemes became very popular in nickel plating, tinning, copper plating and zinc plating processes, as they allow to use the anode material to the full extent and hence save expensive starting materials: nickel, tin, copper and others. In addition, it becomes possible to use ingots, pellets, ingots of primary material that cost much less than their rolled anode equivalents.
Heat Exchangers
In order to achieve high quality deposition of the starting metal, a stable temperature balance must be maintained during the plating process. Today, heat exchangers and coils made of lead, lead-coated carbon steel, and stainless steel are still often used. The problem is that after only two or three months they fail under the influence of aggressive chemical environment of electrolyte and high temperature. The constant repairs and replacements of heaters required in this case are such an undesirable disruption of the temperature established balance, hence the increased cost of operating the equipment.
The use of titanium in heat-exchange equipment is more advantageous compared to the above materials. This explains the increasing popularity of titanium in western production. For example, British company "Dean Productive Incorporated" produces by its own development all-titanium panels used for electrolyte heating. The American company Imperial Chemical Industrial produces titanium coils, and the American company Contimet produces titanium heat exchangers for heating various types of electrolytes (even chromium ones). Thanks to the absence of corrosive products on the external surface of the heat exchanger, the required heat transfer rates can be achieved with a reduction of the heating surface by up to 45%, which is an undeniable advantage.
Cost-effectiveness
Even at half the thermal conductivity compared to lead or steel, titanium offers the opportunity to build heater tubes with much thinner walls, as it is characterized by high corrosion and mechanical resistance. It results from the price equality of coils made of leaded carbon as well as stainless steel and equipment made of titanium grade BT1-00 and BT1-0. Moreover, the use of titanium alloys can significantly reduce the operating costs of equipment, increasing the operating time in four to six times.
Even in conventional chromium baths the titanium coils will serve for many years. Plant "Kommunar" in Zaporozhye uses for the heating of electrolyte during chrome plating titanium heaters 3 meters long and Ø 2.5 millimeters, which replaced the obsolete lead coils 7 meters long and Ø 6 millimeters. During four years of operation, this type of equipment has yielded invaluable economic benefits. Titanium heaters are also used on dozens of automatic lines at the Tambov Mechanical Plant.
Hangers and attachments
Titanium has also been widely used in creating hangers for anodizing parts made of aluminum and its alloys. For example, simple aluminum frames very quickly succumb to oxidation and begin to deteriorate. In order to extend their average operating time beyond four to six weeks, it is imperative that the frames be exposed to an alkaline environment. Titanium frames, on the other hand, show no signs of beginning to deteriorate under similar operating conditions even years later. Titanium hangers have also shown their best qualities in tinning and galvanizing processes. They are not susceptible to corrosion, which avoids loss of their valuable material, extends the life of the part and reduces repair costs.
Welding
Manufacturing titanium hangers and frames is fairly easy. The only limiting nuance - it is forbidden to use connections by soldering with hard and soft solders. It is also undesirable to connect parts using bolts and rivets, as these joints can fail in the transmission of electrical current. The highest rate of reliability is demonstrated by the connection using welding.
Tools
A British company specializing in the manufacture of washing machines uses more than sixty tools made of titanium for the anodizing of aluminum parts, as well as over four hundred aluminum fixtures with titanium tips in its technical arsenal. Repairing electroplated pendants is quite expensive, time-consuming and labor-intensive. The use of titanium production elements keeps such repairs to a minimum. In addition, titanium maintains electrical conductivity at a fairly high level over a long period of time.
Experience of use
In Zaporozhye, at the electric apparatus plant, as well as at the "Kommunar" plant, aluminum hangers were previously used in the processes of anodizing and electropolishing of aluminum parts. At that time, the service life of the hangers was only one month. After the introduction of titanium pendants into production, this time was extended to more than a year. This can be quantified in the ratio of 15 titanium hangers instead of 816 aluminum hangers that need to be used during one year of operation.
The British firm Aizi develops new designs and manufactures titanium hangers of varying design complexity. After thousands of cycles the corrosion of titanium equipment of their production is only 0.025 of the cross-section of the entire suspension.
German companies Riedel, Blasberg and others intensively use suspensions of various designs in electrolytes with sulfuric acid base (mainly in anodizing). Titanium or aluminum pendants with titanium contacts are used most often. However, all-titanium designs are more successful in application.
Titanium equipment used for ventilation systems also helps in reducing operating and repair costs, improves the quality of performance, and extends the life of the equipment. Though initial investments in installation of titanium ventilation system are two to three times higher than the cost of standard ventilation made of steel, but titanium ventilation system qualitatively fulfills its functions five to six times longer. The Zaporozhye automobile plant has been successfully using a titanium ventilation system for more than one year.
Cleaning problems
When the production capacity of metal coating shops increases, it is necessary to take more care about the cleaning process of waste water, which contains a huge amount of toxic components (acids and their salts) that are formed during pickling of metals and their hydroxides from anode cleaning. In galvanizing, copper plating and cadmium baths there are large amounts of metal alkaloids and toxic cyanides, whose concentration should be less than 0.1 mg/l, and chromium content in chromium-acid and chrome baths should not exceed 0.5 mg/l.
Special neutralization plants are used to clean wastewater from slag and toxins. In addition to these harmful substances, wastewater also contains a lot of chemical compounds aggressively affecting the state of the treatment system itself and the drainage system. If wastewater treatment plants are just being built or are undergoing major repairs, it is recommended that the tanks for capturing waste substances, discharge pipelines, pumping equipment and stop valves be made of titanium. The use of this metal increases operational endurance and extends the life of the entire equipment system.
Such a system with a capacity of 10 cubic meters, designed to purify wastewater with a high content of chromium and related compounds, has been built and has been successfully operating for several years at the transformer plant in Zaporozhye. Thus for all time of operation in a bath of catching and drain pipeline was not noticed any case of corrosive destruction.
Conclusions
Numerous experience of titanium application in galvanic constructions proves the expediency of titanium elements use. This applies to reliability, quality, durability and economic efficiency of using this material. The use of titanium equipment in the production is an indicator of the company's progressiveness, following modern trends and taking care of performance indicators, reducing labor intensity, reduction of heavy maintenance for the personnel, increase of coating quality, saving electrolyte, water, electricity and steam, reducing production cycle time, increase of equipment durability, improvement of working conditions and growth of production culture.
Buy, price
Evek GmbH sells rolled steel products at the best price. It is formed taking into account LME rates (Londonmetal exchange) and depends on the technological characteristics of production without including additional costs. We supply a wide range of products made of titanium and its alloys. All batches have quality certificate for compliance with standards requirements. With us you can buy in bulk the most various products for large-scale productions. The wide choice, exhaustive consulting of our managers, reasonable prices and timely delivery determine the face of our company. There is a system of discounts for wholesale purchases
Relevance
Thegalvanic method of metal coating is the most widespread. To increase the intensity and efficiency of production and technological processes of electroplating, new electrolytes are used, increasing the temperature and current density. This requires construction materials and equipment that meet the increased requirements of corrosion resistance. In addition to improving technical performance, it is crucial to maximize the service life of the equipment, which depends on the quality of the lining and construction materials. Despite the fact that there are quite a few materials for safe operation of equipment, it is still not possible to solve the problems related to durability and longevity. Lead in chromium and other acidic electrolytes, although chemically resistant, is easily destroyed mechanically. If the lead lining gets damaged, the tub body is subjected to intense corrosion.
Alternative materials
Steel baths lined with vinyl plastic which is resistant to acidic electrolytes are used for nickel plating, copper plating, galvanizing
Corrosion resistance of titanium
Of all the materials that exhibit a high level of corrosion resistance in most electrolytes, titanium alloys are considered the most optimal for use. Titanium is known for its resistance to corrosion in virtually all alkaline, weakly acidic and acidic electrolytes. It is resistant in pickling solutions containing 10% H2 SO4 at 75 °C, but when the concentration rises to 18-20%, it begins to corrode quickly. If nitric acid or its salts are added to the electrolyte as inhibiting additives, the corrosive destruction of titanium can be prevented. In this case, an oxide film is formed on the surface of the metal, which prevents its dissolution. Titanium will also corrode rapidly in electrolytes containing hydrofluoric or hydrofluoric acid. In all other cases the use of titanium as a protective coating in electroplating is extremely promising.
Electroplating equipment
For pretreatment and plating, there are baths, anode baskets, cathode drums, heating coils, hangers, heat exchangers, pipes, filters, pumps, etc.
Baths
Titanium baths for chromium plating are made of BT1-0 alloy. This technology has been used for a long time by "Kommunar" automobile plant and also by Zaporozhye measuring instrument production plant. The use of titanium in chromium baths increases their service life by five to seven times. When Melitopol engine plant instead of traditional baths of steel and lead were installed three baths of BT1-0 alloy, then due to increasing the duration of theirand reducing depreciation charges, electrolyte costs and reducing labor and energy intensity, it was possible to significantly increase the annual revenue figure.
In the electrolytes used in copper plating, nickel plating, cadmium plating, brass plating, galvanizing and silver plating processes, titanium experiences virtually no corrosive degradation beyond hydrofluoric and boronfluoric acid solutions. In addition, it is undesirable to use titanium in combination with media containing fluoride ions because of the difference in corrosion rate when using the anodic circuit and current cutoff.
Replacement of baths made of carbon steel, lined with vinyl plastic or lead, by titanium baths is advisable to stabilize the production process: reducing the frequency of current repairs, maintaining the purity of the electrolyte, increasing the quality of coating, and most importantly - the ability to adjust the temperature or acid balance of the electrolyte. Resistance of titanium alloys to corrosion in the above-mentioned electrolytes makes it possible to reduce the wall thickness by more than half. This makes titanium baths and vinyl lined steel baths virtually identical in cost.
Anode baskets
Three types of anodes are used in baths designed for nickel plating, galvanizing and copper plating: electrolytic, cast and rolled. The latter are most commonly used as they dissolve most uniformly, whereas electrolytic anodes are characterized by more intensive dissolution and sludge formation.
In order to minimize the harmful effects of sludge, the anodes are placed in special "belting" or "chloride" bags which have previously been treated with hydrochloric acid. In this case, the waste reaches only twenty to thirty percent of the total weight of the anodes. The use of anode baskets made of titanium is extremely promising. As early as 1959, Ford developed and put into operation the first anode bins made of titanium. This greatly reduced the maintenance costs of the equipment and increased the daily operating time by four hours.
The anode garbage cans are designed to increase the overall capacity of the operating plant. In addition, it is not necessary to drain the remaining solution from the bath to add anode material to the tank. The anode material is consumed practically in its entirety, maintaining a constant density and ensuring maximum efficiency of its action. Since 1959, they have been used for cyanide and acid copper plating, cyanide white brass plating and bright nickel plating. Introduction of titanium baskets into the domestic production process made it possible to create a fully soluble anode.
VT1-0.
The application of anode baskets made of the BT1-0 titanium alloy at the Melitopol motor works made it possible to raise considerably the annual economic index in the production of nickel-plated parts used in power units. The main indicator of economical efficiency of this innovation is the 100% usage of nickel anodes, whereas before the technology implementation only 70% of all anodes were used. Besides, it is no longer necessary to use copper hooks that were previously used for installation of new anodes, and labor costs for anode replacement are reduced.
Zaporozhye plant "Kommunar" managed to get away from the ratio of income and total consumption of nickel anodes that were not used in future, which was 30% at the automatic line of electroplating. Titanium baskets made of BT1-0 alloy made it possible to significantly reduce the consumption of nickel anodes and to simplify bath maintenance while correcting the electrolyte level.
Anode baskets with special hooks for hanging are created from 0.8-1 millimeter thick titanium sheets. The cross section of the hooks is calculated on the basis of low heat capacity and current density, which is less than 1A/dm.
Bowing
For the high-speed tinning process, titanium baskets are used, which are pre-filled with granulated tin acting as an anode. This anode material significantly increases the productivity of electrolytic tinning by increasing the active current density which is distributed over the whole area of the anode in the basket.
Economic effect
The titanium baskets designed according to different schemes gained a wide popularity in nickel plating, tinning, copper plating and galvanizing processes, as they allow to use the anode material to the full extent and hence save expensive starting materials: nickel, tin, copper and others. In addition, it becomes possible to use ingots, pellets, ingots of primary material that cost much less than their rolled anode equivalents.
Heat Exchangers
In order to achieve high quality deposition of the starting metal, a stable temperature balance must be maintained during the plating process. Heat exchangers and coils made of lead, lead-coated carbon steel, stainless steel are still commonly used today. The problem is that after only two or three months they fail under the influence of aggressive chemical environment of electrolyte and high temperature. The constant repairs and replacements of heaters required in this case are such an undesirable disruption of the temperature established balance, hence the increased cost of operating the equipment.
The use of titanium in heat-exchange equipment is more advantageous compared to the materials listed above. This explains the increasing popularity of titanium in western production. For example, British company "Dean Productive Incorporated" produces by its own development all-titanium panels used for electrolyte heating. The American company Imperial Chemical Industrial produces titanium coils, and the American company Contimet produces titanium heat exchangers for heating various types of electrolytes (even chromium ones). Thanks to the absence of corrosive products on the external surface of the heat exchanger, the required heat transfer rates can be achieved with a reduction of the heating surface by up to 45%, which is an undeniable advantage.
Cost-effectiveness
Even with half the thermal conductivity compared to lead or steel, titanium offers the opportunity to build heater tubes with much thinner walls because of its high corrosion and mechanical resistance. It results from the price equality of coils made of leaded carbon as well as stainless steel and equipment made of titanium grade BT1-00 and BT1-0. Moreover, the use of titanium alloys can significantly reduce the operating costs of equipment, increasing the operating time in four to six times.
Even in conventional chromium baths the titanium coils will serve for many years. Plant "Kommunar" in Zaporozhye uses for the heating of electrolyte during chrome plating titanium heaters 3 meters long and Ø 2.5 millimeters, which replaced the obsolete lead coils 7 meters long and Ø 6 millimeters. During four years of operation, this type of equipment has yielded invaluable economic benefits. Titanium heaters are also used on dozens of automatic lines at the Tambov Mechanical Plant.
Hangers and attachments
Titanium has also been widely used in creating hangers for anodizing parts made of aluminum and its alloys. For example, simple aluminum frames very quickly succumb to oxidation and begin to deteriorate. In order to extend their average operating time beyond four to six weeks, it is imperative that the frames be exposed to an alkaline environment. Titanium frames, on the other hand, show no signs of beginning to deteriorate under similar operating conditions even years later. Titanium hangers have also shown their best qualities in tinning and galvanizing processes. They are not susceptible to corrosion, which avoids loss of their valuable material, extends the life of the part and reduces repair costs.
Welding
Manufacturing titanium hangers and frames is fairly easy. The only limiting nuance - it is forbidden to use connections by soldering with hard and soft solders. It is also undesirable to connect parts using bolts and rivets, as these joints can fail in the transmission of electrical current. The highest rate of reliability is demonstrated by the connection using welding.
Tools
A British company specializing in the manufacture of washing machines uses more than sixty tools made of titanium in its technical arsenal for the anodizing of aluminum parts, as well as over four hundred aluminum fixtures with titanium tips. Repairing electroplated pendants is quite expensive, time-consuming and labor-intensive. The use of titanium production elements keeps such repairs to a minimum. In addition, titanium maintains electrical conductivity at a fairly high level over a long period of time.
Experience of use
In Zaporozhye, at the electric apparatus plant, as well as at the "Kommunar" plant, aluminum hangers were previously used in the processes of anodizing and electropolishing of aluminum parts. At that time, the service life of the hangers was only one month. After the introduction of titanium pendants into production, this time was extended to more than a year. This can be quantified in the ratio of 15 titanium hangers instead of 816 aluminum hangers that need to be used during one year of operation.
The British firm Aizi develops new designs and manufactures titanium hangers of varying design complexity. After thousands of cycles the corrosion of titanium equipment of their production is only 0.025 of the cross-section of the entire suspension.
German companies Riedel, Blasberg and others intensively use suspensions of various designs in electrolytes with sulfuric acid base (mainly in anodizing). Titanium or aluminum pendants with titanium contacts are used most often. However, all-titanium designs are more successful in application.
Titanium equipment used for ventilation systems also helps in reducing operating and repair costs, improves the quality of performance, and extends the life of the equipment. Though initial investments in installation of titanium ventilation system are two to three times higher than the cost of standard ventilation made of steel, but titanium ventilation system qualitatively fulfills its functions five to six times longer. The Zaporozhye automobile plant has been successfully using a titanium ventilation system for more than one year.
Cleaning problems
When the production capacity of metal coating shops increases, it is necessary to take more care about the cleaning process of waste water, which contains a huge amount of toxic components (acids and their salts) that are formed during pickling of metals and their hydroxides from anode cleaning. In galvanizing, copper plating and cadmium baths there are large amounts of metal alkaloids and toxic cyanides, whose concentration should be less than 0.1 mg/l, and the chromium content in chromium-acid and chrome baths should not exceed 0.5 mg/l.
Special neutralization plants are used to clean wastewater from slag and toxins. In addition to these harmful substances, wastewater also contains a lot of chemical compounds aggressively affecting the state of the treatment system itself and the drainage system. If wastewater treatment plants are just being built or are undergoing major repairs, it is recommended that the tanks for capturing waste substances, discharge pipelines, pumping equipment and stop valves be made of titanium. The use of this metal increases operational endurance and extends the life of the entire equipment system.
Such a system with a capacity of 10 cubic meters, designed to purify wastewater with a high content of chromium and related compounds, has been built and has been successfully operating for several years at the transformer plant in Zaporozhye. Thus for all time of operation in a bath of catching and drain pipeline was not noticed any case of corrosive destruction.
Conclusions
Numerous experience of titanium application in galvanic constructions proves the expediency of titanium elements use. This applies to reliability, quality, durability and economic efficiency of using this material. The use of titanium equipment in the production is an indicator of the company's progressiveness, following modern trends and taking care of performance indicators, reduction of labor intensity, reduction of heavy maintenance for the personnel, increase of coating quality, saving electrolyte, water, electricity and steam, reduction of production cycle time, increase of equipment durability, improvement of working conditions and growth of production culture.
Buy, price
Evek GmbH sells rolled steel products at the best price. It is formed taking into account LME rates (Londonmetal exchange) and depends on the technological characteristics of production without including additional costs. We supply a wide range of products made of titanium and its alloys. All batches have quality certificate for compliance with standards requirements. With us you can buy in bulk the most various products for large-scale productions. The wide choice, exhaustive consulting of our managers, reasonable prices and timely delivery determine the face of our company. There is a system of discounts for wholesale purchases
Relevance
Thegalvanic method of metal coating is the most widespread. To increase the intensity and efficiency of production and technological processes of electroplating, new electrolytes are used, increasing the temperature and current density. This requires construction materials and equipment that meet the increased requirements of corrosion resistance. In addition to improving technical performance, it is crucial to maximize the service life of the equipment, which depends on the quality of the lining and construction materials. Despite the fact that there are quite a few materials for safe operation of equipment, it is still not possible to solve the problems related to durability and longevity. Lead in chromium and other acidic electrolytes, although chemically resistant, is easily destroyed mechanically. If the lead lining gets damaged, the tub body is subjected to intense corrosion.
Alternative materials
Steel baths lined with vinyl plastic which is resistant to acidic electrolytes are used for nickel plating, copper plating, galvanizing
Corrosion resistance of titanium
Of all the materials that exhibit a high level of corrosion resistance in most electrolytes, titanium alloys are considered the most optimal for use. Titanium is known for its resistance to corrosion in virtually all alkaline, weakly acidic and acidic electrolytes. It is resistant in pickling solutions containing 10% H2 SO4 at 75 °C, but when the concentration rises to 18-20%, it begins to corrode quickly. If nitric acid or its salts are added to the electrolyte as inhibiting additives, the corrosive destruction of titanium can be prevented. In this case, an oxide film is formed on the surface of the metal, which prevents its dissolution. Titanium will also corrode rapidly in electrolytes containing hydrofluoric or hydrofluoric acid. In all other cases the use of titanium as a protective coating in electroplating is extremely promising.
Electroplating equipment
For pretreatment and plating, tubs, anode baskets, cathode drums, heating coils, hangers, heat exchangers, pipes, filters, pumps, etc. are used.
Baths
Titanium baths for chromium plating are made of BT1-0 alloy. This technology has been used for a long time by "Kommunar" automobile plant and also by Zaporozhye measuring instrument plant. The use of titanium in chromium baths increases their service life by five to seven times. When Melitopol engine plant instead of traditional baths of steel and lead were installed three baths of BT1-0 alloy, then, due to increasing the duration of theirand reducing depreciation charges, electrolyte costs and reducing labor and energy intensity, it was possible to significantly increase the annual revenue figure.
In electrolytes used in copper plating, nickel plating, cadmium plating, brass plating, galvanizing and silver plating, titanium experiences virtually no corrosive degradation beyond hydrofluoric acid and boronfluoric acid solutions. In addition, it is undesirable to use titanium in combination with media containing fluoride ions because of the difference in corrosion rate when using the anodic circuit and current cutoff.
Replacement of baths made of carbon steel, lined with vinyl plastic or lead, by titanium baths is advisable to stabilize the production process: reducing the frequency of current repairs, maintaining the purity of the electrolyte, increasing the quality of coating, and most importantly - the ability to adjust the temperature or acid balance of the electrolyte. Resistance of titanium alloys to corrosion in the above-mentioned electrolytes makes it possible to reduce the wall thickness by more than half. This makes titanium baths and vinyl lined steel baths virtually identical in cost.
Anode baskets
Three types of anodes are used in baths designed for nickel plating, galvanizing and copper plating: electrolytic, cast and rolled. The latter are most commonly used as they dissolve most uniformly, whereas electrolytic anodes are characterized by more intensive dissolution and sludge formation.
In order to minimize the harmful effects of sludge, the anodes are placed in special "belting" or "chloride" bags which have previously been treated with hydrochloric acid. In this case, the waste reaches only twenty to thirty percent of the total weight of the anodes. The use of anode baskets made of titanium is extremely promising. As early as 1959, Ford developed and put into operation the first anode bins made of titanium. This greatly reduced the maintenance costs of the equipment and increased the daily operating time by four hours.
The anode garbage cans are designed to increase the overall capacity of the operating plant. In addition, it is not necessary to drain the remaining solution from the bath to add anode material to the tank. The anode material is consumed practically in its entirety, maintaining a constant density and ensuring maximum efficiency of its action. Since 1959, they have been used for cyanide and acid copper plating, cyanide white brass plating and bright nickel plating. Introduction of titanium baskets into the domestic production process made it possible to create a fully soluble anode.
VT1-0.
The application of anode baskets made of the BT1-0 titanium alloy at the Melitopol motor works made it possible to raise considerably the annual economic indicator in the production of nickel-plated parts used in power units. The main indicator of economical efficiency of this innovation is the 100% usage of nickel anodes, whereas before the technology implementation only 70% of all anodes were used. Besides, it is no longer necessary to use copper hooks that were previously used for installation of new anodes, and labor costs for anode replacement are reduced.
Zaporozhye plant "Kommunar" managed to escape from the ratio of income and total consumption of nickel anodes that were not used in the future, which was 30%. Titanium baskets made of BT1-0 alloy made it possible to significantly reduce the consumption of nickel anodes and to simplify bath maintenance while correcting the electrolyte level.
Anode baskets with special hooks for hanging are created from 0.8-1 millimeter thick titanium sheets. The cross section of the hooks is calculated on the basis of low heat capacity and current density, which is less than 1A/dm.
Bowing
For the high-speed tinning process, titanium baskets are used, which are pre-filled with granulated tin acting as an anode. This anode material significantly increases the productivity of electrolytic tinning thanks to the increased active current density which is distributed over the whole area of the anode in the basket.
Economic effect
The titanium baskets designed according to different schemes became very popular in nickel plating, tinning, copper plating and zinc plating processes, as they allow to use the anode material to the full extent and hence save expensive starting materials: nickel, tin, copper and others. In addition, it becomes possible to use ingots, pellets, ingots of primary material that cost much less than their rolled anode equivalents.
Heat Exchangers
In order to achieve high quality deposition of the starting metal, a stable temperature balance must be maintained during the plating process. Today, heat exchangers and coils made of lead, lead-coated carbon steel, and stainless steel are still often used. The problem is that after only two or three months they fail under the influence of aggressive chemical environment of electrolyte and high temperature. The constant repairs and replacements of heaters required in this case are such an undesirable disturbance of the temperature established balance, therefore, the operating costs of the equipment increase as well.
The use of titanium in heat-exchange equipment is more advantageous compared to the above materials. This explains the increasing popularity of titanium in western production. For example, British company "Dean Productive Incorporated" produces by its own development all-titanium panels used for electrolyte heating. The American company Imperial Chemical Industrial produces titanium coils, and the American company Contimet produces titanium heat exchangers for heating various types of electrolytes (even chromium ones). Thanks to the absence of corrosive products on the external surface of the heat exchanger, the required heat transfer rates can be achieved with a reduction of the heating surface by up to 45%, which is an undeniable advantage.
Cost-effectiveness
Even at half the thermal conductivity compared to lead or steel, titanium offers the opportunity to build heater tubes with much thinner walls, as it is characterized by high corrosion and mechanical resistance. It results from the price equality of coils made of leaded carbon as well as stainless steel and equipment made of titanium grade BT1-00 and BT1-0. Moreover, the use of titanium alloys can significantly reduce the operating costs of equipment, increasing the operating time in four to six times.
Even in conventional chromium baths the titanium coils will serve for many years. Plant "Kommunar" in Zaporozhye uses for the heating of electrolyte during chrome plating titanium heaters 3 meters long and Ø 2.5 millimeters, which replaced the obsolete lead coils 7 meters long and Ø 6 millimeters. During four years of operation, this type of equipment has yielded invaluable economic benefits. Titanium heaters are also used on dozens of automatic lines at the Tambov Mechanical Plant.
Hangers and attachments
Titanium has also been widely used in creating hangers for anodizing parts made of aluminum and its alloys. For example, simple aluminum frames very quickly succumb to oxidation and begin to deteriorate. In order to extend their average operating time beyond four to six weeks, it is imperative that the frames be exposed to an alkaline environment. Titanium frames, on the other hand, show no signs of beginning to deteriorate under similar operating conditions even years later. Titanium hangers have also shown their best qualities in tinning and galvanizing processes. They are not susceptible to corrosion, which avoids loss of their valuable material, extends the life of the part and reduces repair costs.
Welding
Manufacturing titanium hangers and frames is fairly easy. The only limiting nuance - it is forbidden to use connections by soldering with hard and soft solders. It is also undesirable to connect parts using bolts and rivets, as these joints can fail in the transmission of electrical current. The highest rate of reliability is demonstrated by the connection using welding.
Tools
A British company specializing in the manufacture of washing machines uses more than sixty tools made of titanium for the anodizing of aluminum parts, as well as over four hundred aluminum fixtures with titanium tips in its technical arsenal. Repairing electroplated pendants is quite expensive, time-consuming and labor-intensive. The use of titanium production elements keeps such repairs to a minimum. In addition, titanium maintains electrical conductivity at a fairly high level over a long period of time.
Experience of use
In Zaporozhye, at the electric apparatus plant, as well as at the "Kommunar" plant, aluminum hangers were previously used in the processes of anodizing and electropolishing of aluminum parts. At that time, the service life of the hangers was only one month. After the introduction of titanium pendants into production, this time was extended to more than a year. This can be quantified in the ratio of 15 titanium hangers instead of 816 aluminum hangers that need to be used during one year of operation.
The British firm Aizi develops new designs and manufactures titanium hangers of varying design complexity. After thousands of cycles the corrosion of titanium equipment of their production is only 0.025 of the cross-section of the entire suspension.
German companies Riedel, Blasberg and others intensively use suspensions of various designs in electrolytes with sulfuric acid base (mainly in anodizing). Titanium or aluminum pendants with titanium contacts are used most often. However, all-titanium designs are more successful in application.
Titanium equipment used for ventilation systems also helps in reducing operating and repair costs, improves the quality of performance, and extends the life of the equipment. Though initial investments in installation of titanium ventilation system are two to three times higher than the cost of standard ventilation made of steel, but titanium ventilation system qualitatively fulfills its functions five to six times longer. The Zaporozhye automobile plant has been successfully using a titanium ventilation system for more than one year.
Cleaning problems
When the production capacity of metal coating shops increases, it is necessary to take more care about the cleaning process of waste water, which contains a huge amount of toxic components (acids and their salts) that are formed during pickling of metals and their hydroxides from anode cleaning. In galvanizing, copper plating and cadmium baths there are large amounts of metal alkaloids and toxic cyanides, whose concentration should be less than 0.1 mg/l, and chromium content in chromium-acid and chrome baths should not exceed 0.5 mg/l.
Special neutralization plants are used to clean wastewater from slag and toxins. In addition to these harmful substances, wastewater also contains a lot of chemical compounds aggressively affecting the state of the treatment system itself and the drainage system. If wastewater treatment plants are just being built or are undergoing major repairs, it is recommended that the tanks for capturing waste substances, discharge pipelines, pumping equipment and stop valves be made of titanium. The use of this metal increases operational endurance and extends the life of the entire equipment system.
Such a system with a capacity of 10 cubic meters, designed to purify wastewater with a high content of chromium and related compounds, has been built and has been successfully operating for several years at the transformer plant in Zaporozhye. Thus for all time of operation in a bath of catching and drain pipeline was not noticed any case of corrosive destruction.
Conclusions
Numerous experience of titanium application in galvanic constructions proves the expediency of titanium elements use. This applies to reliability, quality, durability and economic efficiency of using this material. The use of titanium equipment in the production is an indicator of the company's progressiveness, following modern trends and taking care of performance indicators, reduction of labor intensity, reduction of heavy maintenance for the personnel, increase of coating quality, saving electrolyte, water, electricity and steam, reduction of production cycle time, increase of equipment durability, improvement of working conditions and growth of production culture.
Buy, price
Evek GmbH sells rolled steel products at the best price. It is formed taking into account LME rates (Londonmetal exchange) and depends on the technological characteristics of production without including additional costs. We supply a wide range of products made of titanium and its alloys. All batches have quality certificate for compliance with standards requirements. With us you can buy in bulk the most various products for large-scale productions. The wide choice, exhaustive consulting of our managers, reasonable prices and timely delivery determine the face of our company. There is a system of discounts for wholesale purchases
