BigPatents India

The present invention provides a process for the manufacture of dense neodymium stabilised ß-Si3N4 -
-SiAION composite, wherein a synergistic composition essentially consisting of Si3N4, AI2O3, AIN, SiO2 and Nd2O3 as starting materials is mixed in proportion to make a total of 100 mole in the mixed batch, passing the powder through 100 mesh, pressing the powder to form green compacts, sintering the green compacts at a temperature in the range of 1700° to 1900°C in nitrogen atmosphere. The process of the present invention provides neodymium stabilised p-Si3N4 - a-SiAION composites by processing a composition from the system Si3N4 - Al2O3.AIN - Nd2O3.9AIN - SiO2 resulting into dense product of the order of > 98% theoretical density with the advantages such as cost effectiveness, high hardness and high fracture toughness. The produced dense ß-Si3N4 -
-SiAION will be useful for low temperature appiications such as wear parts like bearing and roller materials and particularly for grinding and milling operations like grinding balls.