This product is used for anti-discoloration treatment of workpieces after tin plating, and its anti-discoloration cycle is long. The protective agent does not affect the weldability of the workpiece, nor does it change the contact resistance. The 491 tin protective agent can form a dense organic film on the surface of the tin, effectively isolating the corrosive medium from the surface of the tin layer, and has a certain anti-fingerprint effect. In order to prolong the service life of the protective agent as much as possible, the workpiece must be thoroughly cleaned before entering the protective agent. When the color of the protective agent working fluid gradually darkens and the solution gradually becomes viscous, the protective effect gradually decreases, and it is necessary to partially or completely replace the working fluid.
