SOLID-STATE PROPERTIES OF GROUP IVB CARBONITRIDES

Technically relevant solid state properties of the hot-pressed group IVb carbonitrides Ti(CxN1-x)(approximate to 1.00), Ti(CxN1-x)(0.82), Zr(C(x)N(1-x)approximate to 1.00) and Hf(CxN1-x)(approximate to 1.00), such as microhardnesses, electrical conductivities, heat conductivities (from specific heats and temperature diffusivities) and optical reflectances (visible region), were measured as functions of the [C]/([C]+[N]) ratio. Generally the electrical conductivities, heat conductivities and molar heat values increase with increasing nitrogen content whereas the microhardnesses decrease. In samples of the series Ti(CxN1-x)(0.82) a discontinuity in the C-p vs. T curves could be detected at 700-820 degrees C depending on the [C]/([C]+[N]) ratio, indicative of a phase transition. The colour of the IVb carbonitrides changes from yellow through violet to grey with increasing [C]/([C]+[N]) ratio. The extension of the coloured region is greater the higher the atomic number of the metal. A Variety of these properties of IVb carbonitrides were measured for the first time. A literature review is presented.