Hardness and tribological properties of silicon nitride ceramics implanted by titanium ions with MEVVA sources

Hot-pressed silicon nitride ceramics were modified by ion implantation in a MEVVA (Metal Vapor Vacuum Arc) implanter. The samples were implanted by Ti ions with nominal doses from 5 x 10(16) to 1 x 10(18) Ti ionS/cm(2) at ambient temperature. The influences of ion implantation and the doses implanted on the microstructures, mechanical properties and wear performance of ceramics were studied through the characterization of the Rutherford backscattering spectroscopy (RBS), X-ray diffraction (XRD), scanning electron microscopy (SEM), Auger electron spectroscopy (AES), nanoindentation tests, and cutting tests before and after implantation. It was discovered that: (1) with increasing doses of the implanted titanium ions, the nanohardness and Young's modulus increased; (2) Si3N4 ceramics with different amount of additives during sintering showed different change modes in nanohardness and Young's modulus after implanted by Titanium ions under the same conditions; it seems that composite Si3N4 ceramics need higher doses of titanium ions implanted to rehabilitate the voids derived from the preparation processes; (3) the cutting tools prepared by the as-implanted Si3N4 ceramics showed reduction of flank wear and extension of tool life.