Silicon Aluminum Oxynitride is in fact a fine-grained nonporous advanced ceramic material with less than 1 vol.% open porosities. Silicon Aluminum Oxynitride is made of a silicon nitride ceramic with a small percentage of aluminum oxide. Its generally adopted chemical formula is Si_6-xAl_xO_xN_8-x. This superior refractory material has the combined properties of silicon nitride, i.e., high-temperature strength, hardness, fracture toughness, and low thermal expansion, and that of aluminum oxide, i.e., corrosion resistance, chemical inertness, high temperature capabilities, and oxidation resistance.