Abstract
New tungsten carbonitride W(C, N)powder with 11-20 at% nitrogen had already been found by us to be synthesized by heating W+C mixed powder in N2 gas of high pressure(10-160 MPa)at 1523-1773 K. In this work, the synthesis of W(C, N)powder was tried by heating W+C and WO3+C mixed powders in NH3+H2 mixed gas of normal pressure(method I)and by heating W powder in CH4+NH3 mixed gas of normal pressure(method II), mainly at 1573 K for 3.6 ks. This try was based on the general concepts that the reactivities or activities of nitrogen and carbon atoms formed by the dissociation of NH3 and CH4 respectively are enormously high, compared with those of N2 and solid carbon, respectively. It was found that the products obtained by methods I and II were W(C, N) with nitrogen contents of 3 and 5 at%, respectively. The functions of NH3 and CH4 in the carbonitridation of W powder were also experimentally investigated in comparison with those of N2 and solid carbon, respectively.
