TiMoTa multi-component transition layer: Plasma in-situ diagnosis, mechanical properties and effect on diamond adhesion

The transition layer prepared on the cemented carbide surface through double glow plasma surface alloying (DGPSA) is believed to be an effective strategy to improve the adhesion between the diamond and cemented carbide. In this work, to fully reveal and understand the behavior of double glow discharge plasma, DGPSA processes were studied using optical emission spectroscopy (OES), and the effect of the as-prepared TiMoTa transition layer on the diamond growth mechanism and adhesion property was analyzed. The microstructure, composition, and adhesion properties of TiMoTa transition layers and diamond coating were analyzed using SEM, TEM, XPS, XRD, and Rockwell C indentation. The results indicated that the intensity of the plasmas (Ti, Mo, and Ta) remained stable with the deposition time with the increase of deposition temperature, the electron temperature remained in the range of 1 × 104–1.4 × 104 K during the deposition process. OES results showed that the TiMoTa transition layer with a high deposition rate and high performance can be prepared by selecting the appropriate deposition temperature and time through DGPSA technique. The TiMoTa transition interlayers with nanocrystalline structure can effectively restrain the out-diffusion of Co and the in-diffusion of C, thereby effectively improving the adhesion between diamond and cemented carbide. Hence, the TiMoTa transition layer prepared through DGPSA technique offers an effective way to develop a good adhesion diamond coating on WC-Co substrate.