Reactions on interfaces in heterophase TiN-Mo, TiN-W, ZrN-Mo, and ZrN-W materials during sintering
This paper reports on a study of the reactions on contact surfaces of solid titanium nitride and zirconium nitride specimens with molybdenum and tungsten in a vacuum corresponding to 0.01 Pa at temperatures in the range, 1900-2150/sup 0/C. The starting materials were titanium nitride containing 21.3% N and 0.3% O/sub 2/ dissolved in the TIN lattice; zirconium nitride containing 0.6-0.8% O/sub 2/; molybdenum with the impurities 0.02% C, 0.05% Ti, and 0.08% Zr; and tungsten with the impurities of 0.01% Si and 0.02% Hf. Polished end faces of specimens were pressed against each other with a small force, and in that position the specimens were annealed for an hour, after which microsections prepared in planes perpendicular to the control surfaces were investigated metallographically and by electron probe microanalysis. It is concluded that the development of bonds at interfaces between titanium nitride and zirconium nitride on the one hand, and molybdenum and tungsten on the other, is a consequence of diffusional reactions between the elements of the nitride phases and the metals which are accompanied by the formation of metal-base solid solutions localized within narrow contact zones.