Plating is using electrolytic of principle, through metal ion of electrolytic process in products surface deposition a layer metal or alloy layer, to change products surface physical and chemical performance, eventually makes plating zinc Board has wear sex, and decorative sex and resistance impact sex, also also can according to specific products of special requirements and coated covered a species specific of coating, as light sex and electromagnetic sex coating,, such can full expanded plating plate of application field.
Galvanized steel is zinc plated metal, electro-Zn2+ in solution, and then deposited on steel plate, forming a uniform dense layer of zinc metal. Compared with the other metals, zinc is an amphoteric metal, easily soluble in acid, soluble in alkali, more vulnerable to electrolytic metal ions in solution.
Electroplating process mainly after pretreatment, electroplating and coating process, coating depends on the quality of the plating process, and plating processes are affected by many factors affect, summarized as follows:
(1) zinc content: zinc block of zinc purity more high, its light range more narrow, car Board on more get more thick of coating, coating in the iron content also will lower; Dang zinc block of purity too low Shi, its light range will more wide, to reached provides of zinc layer thickness on need more long of time, this on will led to plating zinc layer in the iron content high.
(2) sodium hydroxide: NaOH has a dual effect on the reaction, when the content is too high, high temperature operation prone to burning; and its content is too low, the dispersing ability of solution, this will reduce the zinc coating quality.
(3) the iron content: when the iron content is too high, will more the coating of iron, could result in insufficient brightness film; and iron levels too low will cause low iron content in zinc plating, lower the car plate corrosion resistance, and can lead to car surface is olive.
(4) the brightener: now use brightener by the mixture of ZF-100A and ZF-100B, the former concentration is too high it will make the brittle coating, and too low can result in coating of low current region is sparse, uneven passivation phenomena appeared.
(5) temperature: during the high temperature can cause solution power decline, increased iron content in coatings, passivation is not uniform; and when the temperature is too low, high current densities tend to burn slower larger brittle coating and rate of deposition.
(6) the cathode speed: must ensure that the cathode in the electroplating process is moving, if you move too fast, high current density in the electroplating process deposits are more rough; moved too slow and could produce airflow, resulting in uneven coating of the material.
Because of the excellent corrosion resistance of galvanized sheet, deep molding, paint and welding, as well as good surface quality and mechanical properties and is widely used in areas such as cars and appliances. Electroplating process in relation to the above note, to produce high quality products.