A PbO rich borosilicate glass has been developed as a thick film, dielectric coating for an Al/SiC particle reinforced metal matrix composite (MMC). Sessile drop experiments were performed to investigate interfacial reactions. The wetting behaviour of the glass, highly fluid at the bonding temperature (500-600 deg C), was found to be a function of atmosphere, temperature and time. Coatings applied under air exhibited ~10% porosity attributed to the production of CO2 gas through the oxidation of SiC at the glass/MMC interface. This may occur via oxygen diffusion through the glass drop from the air to the interface or via a redox reaction between the SiC and the lead oxide component of the glass at the glass/MMC interface, the latter generating free lead metal as a waste product.
