As we all know, galvanizing of casters is actually a surface treatment technology that coats a layer of zinc on the surface of the caster alloy, which is mainly for aesthetics and rust prevention. However, there are many methods for galvanizing casters, and the various galvanizing methods are used in different places. The following universal wheel will introduce several methods of galvanizing casters.
1. Cyanide galvanizing
Since cyanide (CN) is highly toxic, environmental protection has put forward strict restrictions on the use of cyanide in the electroplating of caster hardware parts, and continuously promoted the development of electroplating zinc plating liquid systems for reducing cyanide and replacing cyanide caster hardware parts. It is required to use low cyanide (micro cyanide) caster hardware part electroplating liquid. The product quality of the caster hardware part after electroplating using this process is good, especially the color can be well maintained after passivation of the color plating.
2. Zinc plating
The zinc plating process evolved from cyanide zinc plating. Currently, there are two major factions in China:
(1) Wuhan Institute of Material Protection's "DPE" series
(2) Radio and Television Institute's "DE" series
Both belong to zinc plating with alkaline additives; the pH value is 12.5~13. The lattice structure of the coating using this process is columnar, with good corrosion resistance, suitable for color zinc plating.
Typical formula: NaOH--110~120g/l; ZnO--11~12g/l; 94--5~7g/l. 94 is the product code for the combination of "DPE-Ⅱ" and ethanolamine.
Note: After the product comes out of the tank, wash with water, polish (nitric acid + hydrochloric acid) and wash with water, passivate, wash with water, wash with water, iron dry, dry, and age (80~90oC in the oven).
3. Chloride zinc plating
The chloride zinc plating process is widely used in the electroplating industry of caster hardware, accounting for up to 40%. After passivation (blue-white), zinc can replace chromium (comparable to chrome plating), especially after adding water-soluble varnish, it is difficult for laymen to distinguish whether it is zinc plating or chrome plating. This process is suitable for white passivation (blue-white, silver-white). When the customer has no special requirements, it is better to choose silver-white passivation (the color remains relatively stable).
Typical formula: KCl--180~220g/l; ZnCl--65~75g/l; H3BO3--25~30g/l (buffer); PH value is 5~5.5; CI-87--15~20g/l (brightener).
4. Sulfate zinc plating
The sulfate zinc plating process is suitable for continuous plating (wire, strip, simple, large and large parts and components) with low cost.
Typical formula: ZnSO4--300~500g/l; H3BO3--25~30g/l; PH value: 4.5~5.5; Zinc sulfur--15~20g/l (brightener).
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