Effect of sintering procedures on the gradient structure of graded cemented carbides with a cubic carbide-free layer

Graded cemented carbides with a cubic carbide-free layer(CCFL) in the surface were synthesized by one-step sintering.The microstructure,phase composition and element distribution of the graded cemented carbides were investigated by scanning electron microscopy,X-ray diffraction analysis and electron probe microanalyzer,respectively.The typical microstructure of the graded cemented carbides and the effect of sintering procedures on gradient structures in the graded cemented carbides were discussed in detail.It is shown that the depth of CCFL significantly increases with increasing sintering temperature and prolonging holding time,and there exists a linear dependence approximately between the depth of CCFL and the square root of holding time.The depth of CCFL becomes larger at a higher cobalt content,but narrows with increasing Ti(C,N) content for the same sintering procedure.