STA 429 - NETZSCH-Gerätebau - #9

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9 Silicon aluminum oxynitride (sialon) is exceptionally corrosion resistant, has high wear resistance, low thermal expansion and good oxidation resistance. It is widely used in the chemical industry and metallurgy. This figure depicts the TG and DTA curves of a sialon sample in a helium atmosphere. As can be seen, decomposition already starts at approx. 1500°C with mass loss occurring in multiple steps. The first maximum mass loss rate occurs at 1808°C. Thermal stability of sialon Silicon nitride ceramics feature excellent mechanic properties at high temperatures, a small expansion coefficient and low density as well as chemical and thermal shock resistance. Because of these properties, Si3N4 is widely used in metallurgy, chemistry and even in automobile parts such as engine pistons. This figure shows a comparison of the thermal degradation of Si3N4 in helium and in vacuum. Although decomposition begins at similar temperatures, Si3N4 shows a much higher mass loss and at least two significant mass loss steps in vacuum. Thermal behavior of Si3N4