Abstract: Improved silicon carbide powder is prepared by carbothermal reduction of silica by introducing ?-SiC powder simultaneously with iron in the starting composition resulting into a precursor powder which after complete reduction contains at least 90% SiC preferably rich in the ?-phase. The main advantage, among others, is cost effectiveness. Silicon carbide powder finds wide usage in the manufacture of products suitable for refractory and engineering applications.

Abstract: The present invention consists of a synergistic mixture of Si3N4, Al2O3, AlN, SiO2 and Nd2O3. The cost effective synergistic composition is useful for the preparation of dense neodymium stabilised ?-Si3N4-?-SiAlON composite of the order of >98% theoretical density, having high hardness and high fracture toughness. The dense ?-Si3N4-?-SiAlON composite will be useful for low temperature applications as wear parts like bearing and roller materials and particularly for grinding and milling operations like grinding balls.

Abstract: The synergistic composition consists of a mixture of a source of pure silica such as silicon dioxide, a source of carbon such as activated charcoal, ?-silicon carbide and a source of iron such as ferric nitrate. The cost effective synergistic composition is useful for the preparation of improved silicon carbide powder containing at least 90% SiC preferably rich in the ?-phase. Silicon carbide powder finds wide usage in the manufacture of products suitable for refractory and engineering applications.

Abstract: The present invention provides a process for the manufacture of dense neodymium stabilized ?-Si3N4-?-SiAlON composite, wherein a synergistic composition essentially consisting of Si3N4, Al2O3, AlN, 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 stabilized ?-Si3N4-?-SiAlON composites by processing a composition from the system Si3N4—Al2O3.AlN—Nd2O3.9AlN—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.

Abstract: The present invention relates to a process for the preparation of improved silicon carbide powder by carbothermal reduction of silica by inventive steps of introducing ?-SiC powder simultaneously with iron in the starting composition resulting into a precursor powder which after complete reduction contains at least 90% SiC preferably rich in the ?-phase. The main advantage, among others, is cost effectiveness. Silicon carbide powder finds wide usage in the manufacture of products suitable for refractory and engineering applications.

Abstract: The present invention consists of a synergistic mixture of Si3N4, Al2O3, AlN, SiO2 and Nd2O3. The cost effective synergistic composition is useful for the preparation of dense neodymium stabilised ?-Si3N4-?-SiAlON composite of the order of >98% theoretical density, having high hardness and high fracture toughness. The dense ?-Si3N4-?-SiAlON composite will be useful for low temperature applications as wear parts like bearing and roller materials and particularly for grinding and milling operations like grinding balls.

Abstract: The present invention provides a process for the manufacture of dense neodymium stabilised ?-Si3N4-?-SiAlON composite, wherein a synergistic composition essentially consisting of Si3N4, Al2O3, AlN, 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 ?-Si3N4-?-SiAlON composites by processing a composition from the system Si3N4—Al2O3.AlN—Nd2O3.9AlN—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.

Abstract: The synergistic composition consists of a mixture of a source of pure silica such as silicon dioxide, a source of carbon such as activated charcoal, ?-silicon carbide and a source of iron such as ferric nitrate. The cost effective synergistic composition is useful for the preparation of improved silicon carbide powder containing atleast 90% SiC preferably rich in the ?-phase. Silicon carbide powder finds wide usage in the manufacture of products suitable for refractory and engineering applications.