US Patent 10308559 Sintered polycrystalline cubic boron nitride body

A sintered polycrystalline body and a method of forming the sintered polycrystalline body are disclosed. The sintered polycrystalline body comprises a plurality of particles cubic boron nitride dispersed in a matrix. The matrix includes materials selected from compounds of any of titanium and aluminium. The polycrystalline body further comprises 0.1 to 5.0 volume % of lubricating chalcogenide particles dispersed in the matrix. The chalcogenide particles have a coefficient of friction of less than 0.1 with respect to a workpiece material. Preferably sulfide particles are used as lubricant. Preferably 30-70 vol.-% cBN is contained. Sintering takes place at 1100-1600° C. and 4-8 GPa.