Integrated molding of nanocrystalline tungsten carbide powder with stainless steel

Nanopowder of tungsten carbide (d < 100 nm) was prepared by the planetary ball milling of the commercial powder with the particle size of the submicron order. The WC powder was densified by the spark plasma sintering. The milled powder was possible to be densified at a temperature which was 500 °C lower than densification temperature for the commercial powder. The tungsten carbide body sintered at 1100 °C for 3 min under 50 MPa mainly consisted of nanograins with the grain size of <100 nm. It exhibited superplastic deformation behavior under compression at 1200 °C to a strain of >2 without brittle fracture. Applying such superplastic property, we successfully covered the inwall of the cylindrical metal mold made of stainless steel with tungsten carbide layer of the 2 mm in thickness by using spark plasma sintering method.