Aluminium nitride-molybdenum ceramic matrix composites: Characterization of ceramic-metal interface

Pure aluminium nitride can be hot pressed with an addition of molybdenum powder. With this technique we obtain a ceramic matrix composite having a dispersed metallic phase. Composites produced in this manner present a homogeneous structure with very little open porosity. Electrical resistivity measurements done over a series of composites show a sharp decrease in electrical resistivity when the molybdenum volume fraction in the material increases from 0.2 to 0.22. This value corresponds to the percolation threshold of metallic phase in the ceramic matrix. The interface between molybdenum particles and aluminium nitride grains is established through a fine oxide or oxynitride layer present at the surface of AIN grains.