Mechanism of multi-layer composite coatings in the zinc process of recycling coated Wc-Co cemented-carbide scrap

Abstract

The mechanism of a coating is crucial for the zinc-process parameters and zinc-recycled WC powders as well as the subsequent production. The mechanism of a multi-layer composite coating in a zinc process was discussed and the coating with recycled WC powders was studied. The results demonstrated that the coating created a barrier in the zinc process, resulting in a longer recycling time for the coated hard-metal scrap. Furthermore, cracks that appeared due to different thermal-expansion coefficients of the materials were the main reason for the breakdown of the coating, rather than the reaction or the dissolution; and the molten zinc mainly went through cracks. Additionally, the coating elements and fragments were found in the recycled WC powders.