RESEARCH ON INFLUENCE OF Ni AND Cr ADDITIONS IN Co BINDER PHASE ON PROPERTIES OF CEMENTED CARBIDES USED FOR ROLLERS

The mechanism of the effect of Ni and Cr in Co binding phase has been discussed. The resuits have shown that Ni and Cr can promote the stabilizing state phase(f, c. c.) of Co binding phase at high temperature to remain at room temperature completely without transformation to stabilizing phase(h. c. p.) at low temperature with the results of improving ductility of alloy, and at the same time increase thermal fatigue corrosion and oxidation resistance. Furthermore, due to Cr dissolving in Co binder phase to form solid solution, Cr has a passivation effct in corrosive medium and the corrosion resistance of alloy can also be further improved.