Surface characterization of Mo-implanted 6H–SiC by high temperature non-reactive wetting tests with the Ni–56Si alloy

The effects of Mo ion implantation into SiC monocrystalline substrates and succeeding annealing treatments on the interfacial characteristics of 6H–SiC were investigated by means of wettability tests. Ni (reactive) and the Ni–56Si alloy (non-reactive) have been used as liquid phases as a means to evidence the influence of surface and interfacial tensions on solid–liquid interactions. The variations of contact angle as a function of Mo implantation and of temperature are analyzed and discussed. The results indicated that a significant improvement of wettability was mainly related to the increase of surface energy (σSVσSV) of SiC substrate and to the presence of Mo, rather than to the surface roughness of the ceramic substrate. With increasing annealing temperature, the contact angle of the Ni–56Si/SiC system increased as a result of the crystallization of the SiC amorphous surface and the loss of Mo at the substrate surface due to oxidation and diffusion/vaporization. The influence of these phenomena on technological processes such as metal–ceramic brazing is also taken into consideration