The microstructure and some properties of magnesia-alumina spinel materials with sialon matrix

In the pseudo ternary MgO-Si3N4-Al2O3 system at 1800 degrees C the occurrence of liquid phase is limited to areas near the MgO-Si3N4 line, close to Si3N4 The area near the MgO-Al2O3 line is interesting from the point of view of refractory materials The results of investigations into the properties and microstructure of magnesia-spinel materials with oxynitride and nitride matrix obtained by sintering are presented The materials with a matrix composed of AlN polytypoids were characterized by very high refractoriness under load (RUL) in reducing conditions (T-06>1700 degrees C) and relatively high RUL in air (min T-05>1620 degrees C) The TG curves showed that the oxidation course was similar to and depended on the composition and mixture of samples A very good correlation was found between the calculated values of R-st coefficient and resistance to thermal shocks sustained by the cylinders subjected to sudden heating up to 950 degrees C and cooling