Surface Structure For SiC Ceramics Implanted With N~+ Ions And Their Tribological Characteristic In Water

In comparison of lubricative oil, water is no pollution, low cost and safty. However, due to hight oxidative and poor formation ability of lubricative films for water, it is required for the tribological materials in water to have high corrosion and wear resistance and low friction coefficient besides enough mechanical property.In here, SiC ceramics were implanted by N~+ via using ion implantation technology. The phase composition and structure of N~+ implanted SiC ceramics were investigated by using X-ray diffraction and X-ray photoelectron spectroscopy, and their nano-hardness was measured by nano-indenter. The friction and wear properties of the N~+ implanted SiC ceramics against SiC balls in water were investigated by using tribo-meters. The three-dimensional morphologies and wear volumes of wear scars were observed and determined by non-contact surface profilometers, and the wear scars on the N~+ implanted SiC ceramics were observed by scanning electron microscope (SEM). The research results show that the N~+ implanted SiC ceramics are mainly composed of SiC and SiCN phase, and Si-C,Si-N and C-N bonds are formed. The N~+ implanted SiC ceramics at dose 1×1017ions/cm2 has the highest hardness of 22.3GPa. The N~+ implanted SiC ceramics exhibited lower friction coefficient and lower wear rate in conoarison of unimplanted SiC ceramic. When the normal load and the sliding speed increased, the friction coefficient decreases. The lowest friction coefficient of 0.014 for the N~+ implanted SiC ceramics at 50KeV and 1.0×1018ions/cm2 was obtained. With an increase in normal load, the specific wear rate of SiC disk increased. The specific wear rate of SiC disk has the lowest numerical value of 4.4×10-6mm3/N.m at 50KeV and 5.0×1017ions/cm2. The shape of wear scar displayed the parabolic shape continual trench, and the depth decreased after N~+ implantation. The microanalysis showed that the wear surface became flat and smooth besides scratch lines and voids. It indicated that the wear mechanism of SiC in water was mix wear.