In the production process using electroless nickel plating solution, rework is required when the quality of the electroless nickel layer of the workpiece is not satisfactory.And some workpieces have discolored the electroless nickel coating after rework. What is the reason?
Bigolly Technology made an analysis based on the field experience and the characteristics of the product's electroless nickel plating solution Ni-809,there are mainly 2 reasons:
1. When the steel parts are stripped of chemical nickel using the acid nickel stripping solution, it will cause different degrees of corrosion to the base material.At this time, when the workpiece is electroless nickel-plated, the surface will be foggy, and it will be blackened or corroded.Therefore, the substrate should be mechanically polished and ground after stripping.The use of neutral or alkaline nickel-removing solution for iron and steel parts to remove chemical nickel basically has no effect on the base material, and the appearance does not change significantly after the chemical nickel is returned.
2. Improper operation of the aluminum alloy substrate during chemical nickel stripping will lead to excessive stripping. If the substrate is not reprocessed, the coating will be dark and dull when the chemical nickel is reversed.Therefore, when the aluminum alloy workpiece just recedes the chemical nickel layer, the workpiece is taken out and electroless nickel plating is performed again.Then the color change of the chemical nickel layer is not obvious.
This is the reason for the discoloration of the coating after the electroless nickel workpiece is reworked.Therefore, when we use electroless nickel plating solution for production, we should strictly control the plating solution in accordance with the instructions to avoid rework of workpieces and improve production quality.