Selection principle of plating rack material
Core reminder: The material of the hanger can be differentiated according to each process stage and different plating species. The key point is to consider the electrical conductivity, corrosion resistance, and strength requirements of the material within the process range. This article focuses on lye degreasing and acid removal. Principles for selecting materials for corrosion, hard chromium plating, zinc plating, nickel plating, gold plating, silver plating, and aluminum anodizing racks.
The material of the hanger can be differentiated according to each process stage and different plating species. The key point of the selection basis should consider the electrical conductivity, corrosion resistance, and strength requirements of the material within the process range, as well as the necessity and economics. Reasonableness.
Which material should be used for the hanger for lye degreasing?
There are relatively few hangers for lye degreasing, usually tied with wire or installed in a basket. However, no matter what form of loading is used, ferrous materials can be used. If the lye is degreasing, the acid etching process is transferred with the hanger, and the corrosion resistance requirements are often considered at this time. However, if only the film is removed and the film can be removed in a short time, it will not cause excessive corrosion, and there is no need to replace the original hanger or the original binding material.
What kind of material should be used for the acid etching hanger?
Acid etching is similar to lye degreasing, and the use of hangers is relatively small. Most of them are loaded with baskets or lashing methods. If the surface of the workpiece is not severely rusted, iron can also be used. If the oxide scale is thick, titanium or stainless steel should be used.
It is not allowed to use copper hangers, baskets, or copper wires to bind the etched parts in the acid. If the acid is contaminated by copper ions, it will lose its effect, otherwise, it will produce a replacement copper layer on the surface of the etched iron. This affects the bonding strength of the coating.
Which material should be used for hard chrome plating hangers?
Hard chromium plating can choose iron and copper combination hangers, that is, iron is used below the liquid level. When iron ions are mixed into the chromium plating solution during reverse plating before hard chromium plating, the effect of iron ions is much smaller than that of copper ions. , The maximum allowable value of iron in the chromium plating solution can reach 10g/L, while the maximum allowable value of copper is 5g/L, and the strength of iron is better than that of copper, and it is easy to fix the workpiece.
In order to improve the electrical conductivity of the hanger, it is meaningful to use copper for the main rods and hooks above the liquid level. The connection points can be brazed or riveted to be fixed and used after insulation.
Which material should be used for decorative chrome-plated hangers?
Small decorative chrome-plated parts should be bound with thin copper wire plated with a thin layer of nickel or a thin layer of chromium. For larger parts, if there are clips (holes or concealed places), phosphorous plated with nickel or chromium can be used. The copper wire hanger clip should not be used again when there is a thick chromium layer on the hanger, otherwise, it may affect the chromium layer around the hanger.
This kind of hanger must be washed before it is used every other day.
