Zinc nickel alloy plating in the domestic development
Introduction of zinc - nickel alloy electroplating
???????Zinc-nickel alloy plating, is a new plating technology. The coating is no longer a simple zinc layer, but a zinc-nickel alloy layer, which is plated on the steel surface.
????Zinc-nickel alloy is used as a zinc alloy for soldering of steel alloys. The zinc-nickel alloy is usually smelted into Zn-2% Ni alloy and Zn-2% Ni alloy is used as the zinc plating solution with the nickel content of 0.04% ~ 0.09%. Compared with the traditional galvanized layer, Effectively solve the problem of thick steel coating and reduce costs, improve the corrosion resistance of the coating.
????The intrinsic quality control of zinc-nickel alloy plating is mainly to control the proportion of zinc and nickel in the bath, so that the nickel content in the coating reaches a certain content. To do this, the key is to control the ratio of zinc and nickel anode area and the size of the control current (To have analytical means to master zinc, nickel concentration). Appearance quality is mainly good or bad selection of galvanized brightener.
????b. Development of zinc-nickel alloy plating Background:
????Zinc alloys are zinc cobalt, zinc iron, zinc and nickel. Among them zinc-nickel coating corrosion resistance is the highest, mainly refers to zinc 90% to 95%, nickel 50% to 10% of the alloy. This type of alloy has been practiced for many years in many areas of the world. For example, galvanized nickel alloy sheet has been in the automotive industry and the computer industry to provide excellent production of rough, greatly improving the corrosion resistance. Zinc-nickel alloy plating of automotive components such as fuel pipes, actuators, transmission components in some European and American countries have been standardized in the design of a wider range of applications in Japan.
????c. Zinc-nickel alloy plating in the domestic development
????(1) In March 1992, Yuan Guowei, a two-light institute in Guangzhou, proposed that the zinc chloride coating with bright and leveling in the acid chloride plating solution was excellent in appearance and corrosion resistance after blue passivation treatment.
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????⑶ June 1992 Beijing University of Aeronautics and Astronautics Zhu Liqun, Luo Dili study of zinc-nickel alloy coating coated with organic paint in 5% sodium chloride solution and hydrochloric acid acid mist corrosion resistance, containing nickel l0% ~ l5 % Of the zinc-nickel alloy coating corrosion resistance is best.
????⑷ l993 year of the export of the United States and the United States, the United States, the United States, the United States, the United States, the United States, the United States, the United States, the United States, the United States, the United States, the United States, the United States, the United States, the United States, Excellent corrosion.
????⑸ September 1997 Du Weiyi, Li Yi (South China University of Technology) to study the alkaline plating of bright zinc-nickel alloy, synthetic TD additives, access to high corrosion resistance of nickel l2% ~ l3% zinc-nickel alloy coating.
????In June 1997, the proposed formulation of zinc chloride alloy plating for chloride plating was discussed. In 1998, the anomalous co-deposition and normal co-deposition of zinc-nickel alloy were discussed.
????(7) The 721-3 additive was used in the chloride bath and ZQ1 was used in alkaline plating solution.
????⑻ Xu Jianchun et al. (Shanghai Institute of Light Industry) successfully developed a continuous plating of semi-bright zinc-nickel alloy plating additive NZ-A.
????⑼ 1996 Lu Jintang (South China University of Technology) and other research to ammonia as complexing agent, dimethylamine and ethylenediamine as additives of alkaline zinc-nickel alloy plating process.
????In the case of citrate system, 791 brightener and polyether polyol were used as additives to obtain fine crystalline zinc-nickel alloy coating.
????⑾ 1993, Guangzhou Jin Dianchuang Technology Co., Ltd. Lu Anmin Through the micro-acid and alkaline zinc-nickel alloy plating and conversion film test, the development of corrosion resistance than zinc 5 times higher than the cadmium three times the zinc-nickel alloy coating, passivation The film is bright five colors, military green and black D93.
????The relationship between the composition, chemical composition, phase composition and crystal structure of XZN-2 combination additive on zinc-nickel anomaly co-deposition was proposed in 1993.
????(4) In 1994, Xionggang, Zou Qun, etc. (Wuhanbushubao) used NZ-918 series additives in alkaline galvanized nickel alloy plating solution to Dk0.5 ~ 6A / dm2 get the appearance of bright nickel 8% ~ l0% zinc Nickel alloy.
????(8% ~ l0% Ni) alloy coating passivation formula, passivation film stability, and its corrosion resistance than the passivation of more than 2 times higher than the original.
????⒂ 1988 Jiangsu Yangzhou electroplating factory Xia Zhenhua in high concentrations of nickel chloride and zinc sulfate acetic acid type galvanized nickel alloy plating solution, in the higher Dkl5 ~ 30A / dm2 plating bright and fine coating.
????In 1993, Xiamen University Yang Fangzu, Xu Shukai and so on in the containing DIE and AA-1 combination of additives in the alkaline zinc-nickel plating solution was combined with bright zinc nickel (5% ~ l0% nickel) alloy coating.
????d. on the current situation of China's zinc-nickel alloy plating a little bit of view
????China's zinc-nickel alloy research began in the eighties of last century, which are studied by the acid chloride plating process. In the ensuing study, the experts successfully solved the technical key to acid chloride electroplating of zinc-nickel alloys - to find and determine the best combination of additives to effectively suppress nickel deposition in low-cathode current density areas. As a result of this breakthrough, the process can be used for the shape of the more complex iron and steel pieces of the plating, can also be used for barrel plating. Since 1993, a number of units have been put into industrial mass production with this process. One of the main processing products is cable bridge, which has reached 1-2 million tons in the last ten years. It is reported that acid zinc-nickel alloy plating in the nineties of last century began to be used for industrial production, but regardless of its application of the product variety and quantity are in the initial stage, as alkaline zinc-nickel alloy plating in the nineties has not seen For industrial production.
????Zinc-nickel alloy plating in China's rapid development of the popular or recent years, but the development of only alkaline zinc-nickel alloy plating, acid zinc-nickel alloy plating has not been the corresponding development. As mentioned above, acid zinc-nickel alloy plating and alkaline zinc-nickel alloy plating process characteristics and acid galvanized and alkaline galvanized similar characteristics, the choice of technology depends on the shape of the workpiece (except for some steel) , Some suitable for alkaline technology, and some suitable for acid technology, therefore, according to the use of zinc-nickel alloy plating process should be the proportion of acid galvanized and alkaline galvanized ratio is close to, and should not be disparate differences.
????It is understood that China's acid galvanized accounted for more than 50% of the total galvanized, alkaline galvanizing about 40%, while the acid zinc-nickel alloy plating although no national statistics, but we estimate that no more than 10%. Acid zinc-nickel alloy plating the proportion of such a low reason is that a large number of acid zinc-nickel alloy plating should be commonly used in the current commonly used alkaline zinc-nickel alloy plating process. Only according to the coal mine hydraulic pillar, for example, the national use of more than 1 million, countless for this electroplating unit commonly used alkaline zinc-nickel alloy plating process rather than acid zinc-nickel alloy plating process. According to the experts of these two processes of research and development and production practice, such processing of nickel in the same coating content, coating thickness of the same, similar corrosion resistance, the use of acid zinc-nickel alloy plating process cost can be reduced by 50% , Production can be increased more than 2 times. Here we do not intend to cause China's zinc-nickel alloy plating in recent years, two processes are not common reason for the development of the reasons for the discussion, but only to predict this situation will change in a few years, acid zinc-nickel alloy plating process will gradually increase To its proportion