RESUMO
To deposit well-adhered diamond coating, gradient-modified hafnium carbide-silicon carbide (HfC-SiC) mixed bi-interlayers were prepared on cemented carbides (WC-Co) by plasma surface metallurgy technique under the different tetramethylsiline (TMS) flow rate increment. The effects of the TMS flow rate increment on the composition, microstructure, adhesion, and hardness of the bi-interlayers were investigated. Then, the well-adhered bi-interlayer was chosen for the deposition of the diamond coating. It was found that the HfC-SiC mixed bi-interlayers consisted of a diffusion-modified HfC-riched inner layer and a SiC-riched outer layer. The TMS flow rate increment played a key role in tailoring the surface morphology, thickness, and interface character of the bi-interlayer. The dense nanocrystalline diamond coating was formed on the optimized bi-interlayer at the increment of 0.20 sccm/2 min. The diamond coating showed excellent adhesion, which was benefited from the cobalt (Co) diffusion inhibition, gradient composition distribution, and mechanical interlocking.
RESUMO
A Ta coating has been successfully fabricated on the surface of zirconia polycrystals ceramic (3 mol% yttria, 3Y-TZP) by a plasma surface alloying technique. The X-ray diffraction (XRD) and scanning electron microscopy (SEM) results showed that a α-Ta coating with a continuous and compact surface morphology which consisted of a deposited layer with a thickness of 390 nm and a diffusion layer with a thickness of 200 nm covered the 3Y-TZP. Due to the effect of inhabitation the tâm transformation by the deposited Ta coating, the biaxial flexural strength caused by the phase transformation during hydrothermal aging is reduced e.g. p < 0.05 after 20 h and/or 100 h. In addition, the Ta coating shows non-cytotoxicity and improved proliferation ability of osteoblasts.