Effect of Ta diffusion layer on the adhesion properties of diamond coating on WC-Co substrate

Abstract To enhance diamond nucleation and adhesion on cemented carbide substrates, the Ta diffusion layers with gradient structure were deposited by the combination with double glow plasma surface alloying technique (DGPSA) and the reverse-sputtering process. The effect of reverse-sputtering times on phase composition and morphology of the Ta surface layers was studied. It was found that both the thickness of the Ta deposition layer and the amount of Ta elements decreased during the removal of the Ta deposition layer. With the reverse-sputtering time increases from 0 to 60 min, the thickness of the Ta deposition layers decreased from 1.6 μm to 0 μm. When the reverse-sputtering time reached 30 min, the as-prepared sample surface exhibited the maximum micro-hardness (3496.3 HV1.96N). Rockwell C indentation tests were used to investigate the effect of the Ta diffusion layers on the adhesion between the WC-Co substrate and the diamond coating. The results show that diamond coating exhibits good adhesion performance on WC-Co substrate with the Ta diffusion layer after reverse-sputtering for 60 min, indicating that the barrier effect of cobalt diffusion is enhanced by introducing the Ta diffusion layer.