From Earth Minerals to Nitrides

摘要

Structural ceramic parts such as those made from Si_3N_4 or SiAlONs are promising for considering them in replacing metals in the areas where harsh environmental conditions like abrasive corrosion under high stresses along with high temperature effects are dominant. A widespread use of these ceramics depends on the ease of finding them with low cost. This paper highlights some important points on the low cost production technique of Si_3N_4 or SiAlON ceramics in powdered form via carbothermal synthesis technique using minerals in the light of the current and previous works. The technique gives flexibility of controlling production parameters that affect on the yield and quality of powders produced. A special account is given to the effects of reactants on the production of such ceramic powders. After synthesising ceramics in powdered form, some comparisons were made on the characterisation of the products of homemade ones with that of commercially available ones. After successful experimental works, a raw material of orthoclase clay mineral exhibited a high transformation potential to a mixture of Si_3N_4 and SiAlON type ceramic powders.