The effects of flux additions on the sintering and metallizing properties of alumina ceramics were investigated. Experimental results showed that the addition of SiO2, CaO and MgO as a flux increases the sintering ability of alumina. An increment in the amount of MgO seems to produce a more uniform and finer grain distribution. CaO and MgO addition seemed to promote a glassy state of the SiO2 easily at a lower temperature. Alumina containing the proper amount of flux additions showed a higher metal-to-bond strength than nearly pure alumina ceramics. This was explained by the fact that the glassy state of SiO2 migrated into the porous metallizing layer during the metallization process.

Keywords: Mo-Mn metallization, Flux composition, Reduction sintering.