More and more tooling is being made from carbide as these materials have higher service life. In addition to this, carbides are often coated with PVD coatings such as TiN and TiAlN to further extend their life and to improve productivity. At some stage, these parts require refurbishment which is a process of stripping of old coating, re-grinding and re-coating. It is very important to preserve the surface integrity so that after refurbishment the new coating can properly adhere to the surface.
What Is Carbide?
A “carbide” is made up from two phases: a binder and a hard carbide phase much like concrete is made from cement and stones. Various types of binders and carbides are used, the most commonly being cobalt as a binder and tungsten carbide particles. These materials are thus commonly referred to as “tungsten carbide” or just “carbide”.
Special care has to be taken with de-coating of carbides as chemicals commonly used to strip PVD coatings preferentially corrode the cobalt binder. Consequently, carbide particles are removed from the surface, leaving a dull, rough surface.Pitting, blunting of sharp edges and poor surface finish are also typically experienced. And parts cannot be re-coated if this effect is even mild.
TD Coating Centre uses a safe, corrosion free solution to achieve a bright and defect free surface after de-coating. Our solution shows zero loss of cobalt from the surface after 6 decoating runs (see graph).
For more information to safely and effectively de-coat carbide, please contact us.