Layered machinable ceramics for high temperature applications

Abstract

We have identified, fabricated and characterized two classes of layered ternary compounds; the 312 and the H-phases that can be best described as being polycrystalline nanolaminates. Electrical conductivity measurements, high temperature deformation studies as well as compelling microstructural evidence all lead to the conclusion that relatively weak bonding between the metametal and transition metal carbide or nitrides layers sandwiched between them are instrumental in endowing these compounds with excellent machinability, hardnesses in the range of 3-6 GPa, electrical conductivities in the range of 2-5 × 1066 Ω-1m-1, high yield points and significant plasticity at temperatures as high as 1300°C in air.