Electroplating Zinc-nickel Alloy Process

Electrodeposited zinc alloy process technology discussion Guan Bianjie Auto Group heat treatment plant, Jilin Changchun I3Oolll gold plating solution after the acquisition of bright light, good adhesion, high corrosion resistance of the nickel content around the plate zinc alloy coating layer of antimony alloy solution The performance and coating performance were further tested to meet the requirements of the first gas vehicle company's Big Ash Company. 1 Introduction With the rapid development of modern, industry, and science and technology, the material technology has undergone a rapid development. The performance of composite gold itself and the development of foreign applications, it can be affirmed that zinc-bismuth alloy plating is a metal coating process with a wide range of development prospects, and it has been widely adopted in Japan, the United States and Europe. Until the 1990s, domestic research on the electroless forging of zinc-metal alloys was conducted extensively. Although practical applications were obtained, the overall application rule was still very small. The nickel content of the Zinc-plated gold plating process is generally controlled at the level of the intestine.

Electroplating and Finishing Volkswagen AG, the Volkswagen Group, refers to the requirements of the German Volkswagen alloy's alloys. According to the technical standards of Germany and the public, pay for the zinc 4 and the alloy forging solution! It should be the weak acid 1 solution and zinc 4 臬 alloy plating nickel content in a series of technical requirements such as 1 series, but there is no mature technology that meets the requirements of its technical standards before 1 niobium, so we have carried out the zinc cyanide process again. Select and Grind 2 Potassium Chloride Wed Ammonium Electrolyte Electrolytic Zinc Plating 4 Table Alloy Zinc Alloy Coatings Available in various types of electrolytes, mainly sulfate type chloride type sulphate type pyrophosphates Type sulfamate type cyanide type in which the chloride type has the best comprehensive effect, so the choice of potassium chloride ammonium ammonium chloride type 2.1 electrolyte composition and process conditions of potassium 150200 ammonium 507, boric acid 23,81 ten Sodium alkylsulphate 0.068 A few; Complexing agent 318 723 Additives 2, Electrolyte composition and its effect Zinc chloride and nickel chloride provide zinc iono-deuterium nickel ion to the electrolyte. By changing the concentration ratio of zinc to nickel in the electrolyte

The ratio of zinc to nickel in the coating can be controlled, which has a great influence on the crystal appearance and composition of the coating. 12.2 Conductive salts Potassium chloride and ammonium chloride are used as conductive salts to increase the conductivity of the solution and reduce the electrical conductivity of the tank. In addition, chlorination Ammonium also acts as a complexing agent, forming complex ions with 2 and 2+, and raising the critical 1 value of the precipitated zinc hydroxide from the original 4.7 to about 7 to make the electrolyte more stable. 3 buffer electroplating zinc-nickel alloy solution, the value of control than the nickel plating solution is more. To buffer near the call surface, ensure that the composition of the alloy coating is uniform and stable. 2.2.4 Complexing agent The complexing agent forms a complex ion with zinc or nickel ions and improves the cathodic polarization. Make plating. Crystalline smooth, smooth and smooth 2.2.5 Additives play a bright role, and can increase the dispersion capacity of the bath. At the same time, the effect of the current density on the nickel content of the coating is reduced to act as a wetting agent, which can reduce the interfacial tension and reduce the gas in the Cathodic clothes stay on the surface, standing to reduce the coating pits and pinholes, so that the neodymium layer neat product light elimination 3 factors affecting the nickel content of the plating 3.1 plating solution, 12 +, the concentration ratio of the nickel content of the coating rise, The nickel content in the coating was reduced, and the nickel content of the coating was 1 at a concentration ratio between 1.2 and 1.7.

Although the standard electrode potential of zinc is much lower than the standard electrode potential of gallium, the percentage of zinc contained in the zinc alloy plating of 4 gallium has its percentage in the electrolyte, that is, zinc is preferentially deposited than nickel, so The co-deposition of zinc and alloys is a typical anomalous co-deposition. There are several doctrines about the mechanism of this abnormal co-deposition. It is convincing that the concentration of hydrogen near the cathode surface decreases due to the deposition of hydrogen at the cathode surface. High, leading to the formation of 0 and 2 film preferentially generated and adsorbed on the cathode surface alloy components of zinc from the (4) Y film to reduce precipitation, and the nickel component of the alloy is a solution of 1 through 71. film, and The resistance of the stocks is large, and the inhibition is the cause of the abnormal co-deposition of zinc-bearing alloys. From 1 can also be seen, due to the existence of the cathode surface, Per2 film, + reduction control step is produced in! 02 The diffusion step in the film and the coefficient of expansion at this time is very small. In this situation, even if the concentration + force in the bath + film (1) is greatly reduced, the nickel content in the coating does not change. In proportion to the change, only slightly, plus, but in order to get the specified composition of zinc-nickel alloys also need to strictly control the concentration of zinc ions and nickel ions, 3 + 10, for example, every 10 yards of sodium sulfate 06 blood 0 heart, 8 Edition light only, mouse. 1 Zhi Mingqi 6 Follow-up 2 Zhongyu 01 When hunger strikes, the formation of hydroxide precipitates in the industry leads to instability of the bath. In the whole electric process towel, the value of the plating solution must be strictly twisted. 3.4 Effect of plating solution temperature on nickel content in the coating. Test result 4 In the electrodeposition of zinc and alloy, the deposition rate of nickel is relative to Wei's deposition rate. Slowly, the reaction rate increases as the temperature rises. The rate of diffusion of 1+decimal 1 in the film also increases, so that the nickel content of the forging increases with temperature, while the effect of increasing the cathodic current density of 3.2 on the nickel content in the coating is from 2%, and the current density is in the range of 15 persons2. With the increase of cathode current density, the nickel content in the coating rapidly decreases. This shows that the density of Tunliu is low and the reaction speed is small. The increase of 1.1 near the critical surface is not obvious, and a complete film cannot be formed on the cathode surface, so nickel deposition occurs. Not blocked. Nickel is preferentially deposited. As the cathodic current density increases, it gradually forms a 2 and 2 film, and the resistance to puncture through the B40 film gradually increases, making the nickel coating fTfFlf, which has formed a constant thickness of 24 on the pole surface. 2. At this time, the nickel deposition was severely retarded. According to the law of abnormal co-deposition, when the current density increased, many aspects were reduced and precipitated, making the cathode surface thicker; the other side, zinc deposition force 1 The film 2 was thinned, and the restraining effect of the buckle film on 1+ weakened the imitating surface interaction wall. This kept the balance so that with the cathode current density, the nickel content in the plating layer was slightly increased.

4 Electrolyte Performance Test 4.1 Cathodic Current Efficiency Test 4.2 Dispersibility Test Using the Haring Groove Test Method to Test the Effect of Electrolyte on the Cathode The current density is greater than 10 to follow the current density, increase, reaction rate Accelerate, 2 massive precipitation, make. The ytterbium can not be formed at the extreme, and the polarization process is controlled by the diffusion step, resulting in rapid increase of the nickel content of the plating layer. The resulting plating is not loose to say that the 3.3 plating solution, a value of nickel content in the forged layer of the test results 3 zinc The level of nickel content in the alloy plating bath is significantly affected by the nickel plating content. As the value increases, the nickel content of the coating increases linearly. If the value of 1 is too low, then the content of nickel will exceed the best level. ;1! The value is too low, the zinc anode self-dissolution rate is accelerated, the + rich injection in the bath is rapid, and the helium plating is set to set the liquefaction value of the helium-cored carbide to be overdone. The enamel nickel enamel is stuffed (1) Electroplating and finishing 5 Zinc alloy Test of Coating Properties 5.1 Bonding Test of Zinc and 4 Table Alloy Coatings Using the heating and cooling test method, the samples were incubated in a 30-toner oven and then cooled in 153 ç–‹ cold water. There was no blistering and good adhesion. .

5.2 Refractory corrosion resistance test of alloy forged layer at the resignation table Using sulfur oxide industrial gas corrosion test Test conditions 1 Sulfur oxide concentration 0.6; 2 Cycle stage 8 with preheat time, temperature 4 to 3, relative humidity about 3 cycles Test Phase 161 contains the cooling time to open the test chamber or ventilation, the temperature is 1828, the relative humidity is maximum 7; 4 every 2 is the cycle of the sample Zn 4 gold plating thickness is 12, helium, plating he greedy all more than 3 cycles, no substrate rot The corrosion of pool zinc 416 gold coating is determined by the performance of its helium layer. The amount of nickel containing about 13 zinc 41 alloy is a single 7 phase, is an intermetallic compound on the steel matrix, containing about 1 nickel in the amount of zinc, the alloy coating is still anodized, the substrate can play an electrochemical protection.

At the beginning of the corrosion, the zinc in the coating is more likely to be corroded, so that the content of the coating in the coating is reduced, the nickel is relatively rich, and the nickel's rich body is inhibited from corrosion by zinc rejection. The corrosion product of the alloy coating is not conductive, and the coating is uniformly dense. In the plating layer, the coating also plays a protective role, making the zinc alloy coating corrosion resistance is much higher than the zinc coating.

6 Conclusion The use of the weak acid electro-galvanizing nickel alloy process can obtain a bright appearance with good adhesion. Corrosion resistance is high. The nickel content needs to be changed with a preferred method to optimize the chemical polishing process of aluminum products before the 1 oxidation. Must be chemically polished or chemically polished. Acidic chemical polishing processes commonly used today are based on capacity; temperature is 90100, time is 0.52, and nitric acid produces a large amount of red-brown nitrogen oxide gas during polishing, which seriously affects workers' health. Therefore, we Considering that nitric acid is not used, the re-optimum polishing process will have a ratio of sulfuric acid phosphoric acid in the ratio of 1.5 to 1. The mass ratio at 0.51 does not change, and the mass decreases slightly to 1.25, because phosphoric acid is almost ten times more expensive than sulfuric acid, allowing In the range, sulfuric acid should be used as much as possible, so the ratio of the phosphoric acid and the sulfuric acid is taken as 120150. In the temperature range, the 0.618 method is used for the best = the fixed time is 55 3, the temple is 53, and 8 is within the time range. Using the 1618 method, the temperature is preferred. After the optimization, the process conditions are: phosphoric acid 8 irrigated 5 dephosphoric acid 1845 phenol by capacity; temperature 142; time 8, the process after pregnancy reform not only ensures product quality, improves ergonomics, improves working conditions, but also reduces production costs. 4 Take off, received the shirt of the environmental protection department, Anhui Feng said that 7 sets of Gan biological, limited company Hu Guangjun

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