DEPOSITION AND CHARACTERIZATION OF REFRACTORY TERNARY PHASES - THE TRANSITION-METAL NITRIDE TI1-XMOXNY

Differences in the number of valence electrons and atomic mass in the transition metals of ternary nitride phases cause relevant evolutions in the physical properties of these refractory coatings. This report p resents results on structural and mechanical investigations in the Ti1 -xMoxNy system. Thin films are deposited by RF reactive magnetron sput tering from two metal targets. Different structures corresponding to a wide range of chemical composition determined by electron probe micro analysis are obtained by varying the nitrogen partial pressure and the discharge powers. The crystallographic phase is analyzed by X-ray dif fraction: for 0 less than or equal to x less than or equal to 0.79 and 1.65 less than or equal to y less than or equal to 1.04. the samples are single phase face centered cubic. For 0.5 less than or equal to y less than or equal to 0.65 the phase transition from gamma-Mo2N to fac e centered cubic occurs. The steepness of the transition is related to the titanium current. The microhardness H-K is measured by Knoop inde ntation. For 0.06 less than or equal to y less than or equal to 0.17 t he microhardness is higher than for pure molybdenum. For y approximate to 0.5 the highest values are reached for x = 1. Increasing y, H-K in creases and reaches, for 0.40 < x < 1.00. a value 40% higher than sput ter-deposited TiN. The correlation between the change in mechanical an d structural properties is discussed within the ranges of x and y.