Application of the mirror method to the study of chromium doped and zirconium ion implanted sapphire

The space charge theory considers the sites trapping as a local defect of dielectric susceptibility. Thus, impurities or vacancies introduced in the alumina lattice could contribute to trapping. This paper presents the effect of chromium in sapphire single crystals (Rubis) and the effect of the ion implantation of zirconium in the surface of sapphire. The charging capacity has been studied using the “Mirror Method” recently developed to characterize the breakdown parameters. Chromium increases the stability of the trapped space charge but changes little the energy of traps. After zirconium implantation followed thermal treatment, two different energies of traps are measured and trapping occurs at high temperature (up to 220°C). Mechanical properties can be modify by a space charge. We present the tribological behavior of the doped sapphire (with Cr and Zr) under low condition of friction. The Al₂O₃-ZrO₂ layer favors a low friction coefficient