Porous cubic boron nitride based material suitable for subsequent production of cutting tools and method for its production

摘要

The present invention relates to a method of making a PcBN cutting tool insert. The method includes the following steps: mixing raw material powders i.e. cBN and one or more of hBN(hexagonal boron nitride), TiC, TiN, Ti(C,N), WC, W, C, Co, Co2Al9, Al, AlN, Al2O3) with a liquid (e.g. ethanol) and a pressing agent (e.g. polyethylene glycol, PEG) to form a homogeneous slurry with desired composition forming powder agglomerates, typically 100 mu m in diameter, preferably by spray drying forming a body with desired dimensions and density using conventional tool pressing technology. removing the pressing agent from the body at a suitable temperature and atmosphere raising the temperature to 1000-1350 DEG C in vacuum. solid state sintering the body at 1000-1350 DEG C in vacuum for 1-90 minutes to form a body with 35-55 vol-% porosity optionally, adding 0.5-1000 mbar of nitrogen to the sintering atmosphere at the hold time or during cooling HP/HT treating the porous body to form a dense body of desired shape and dimension.