Microstructure and mechanical properties of novel ternary electroconductive ceramics

摘要

Electroconductive ceramic composites, constituted of an insulating matrix (a composite AlN-SiC) containing 30 vol percent of an electroconductive phase (MoSi_2, ZrB_2, or ZrC), were densified through hot-pressing. Microstructure and mechanical properties were compared to those of the AlN-SiC matrix material. All the ternary composites are good electrical conductors, with resistivities in the range 0.3 X 10~(-3) to 4 X 10~(-3) OMEGA-cm. Room temperature properties are improved by the addition of the electroconductive particles. Strength and toughness measurements at high temperature show that MoSi_2-containing composite is stable up to 1300 deg C (strength 611 MPa, toughness 3.7 MPa-m~(1/2)), whereas ZrB_2-containing composite is stable up to 1000 deg C. ZrC-containing composite is not suitable for high-temperature applications due to poor oxidation resistance.