Verfahren zur Herstellung von sauerstoffhaltigen Hartstoffen und deren Verwendung

A process for producing an oxygen-containing hard material of stoichiometric or sub-stoichiometric composition involves (a) subjecting a group IVb or Vb metal oxide or a mixture of group IVb, Vb and VIb metal oxides or one or more metals of groups IVb and/or Vb, groups IVb, Vb and VIb, groups IVb and VIb or groups Vb and VIb and one or more group IVb, Vb and VIb metal oxides to grinding and homogenising with carbon in a molar ratio corresponding to the stoichiometric composition (SC) or the sub-stoichiometric composition (SSC); (b) continuously or discontinuously heating the powder mixture at up to 2500 deg. C, with one or more holding stages of 1 min. to 5 hrs. when discontinuous heating is used; and (c) cooling to room temperature. The stoichiometric composition (SC) is Me(CxNyOz), where x+y+z = 1, z = at least 0.1 and Me = group IVb and/or Vb metals, group IVb, Vb and VIb metals, group IVb and VIb metals or group Vb and VIb metals, and the sub-stoichiometric composition (SSC) is ide ntical except that x+y+z = at most 0.95 and z = at least 0.05. USE - The hard material is used in composite materials for bearings, for throw-away cutter tips, as grinding medium or as magnetic head substrates; in composite materials of oxygen-containing hard materials and oxides, especially for a black ceramic; and, with an average particle size of at least 5 microns, for coating steels (claimed). ADVANTAGE - The process permits production of oxycarbides, oxynitrides, oxycarbonitrides, mixed oxycarbides, mixed oxynitrides and mixed oxycarbonitrides which have a stoichiometric composition or novel sub-stoichiometric compositions and which have properties equivalent to or better than those of conventional materials, allows use of coarse starting material powder and allows production of e.g. sintered ceramics with a relatively dense fine grained structure and with relatively high hardness from coarse oxygen-containing hard materials