Sinteradditive und Si02-enthaltende Siliciumnitridwerkstoffe, ein Verfahren zu deren Herstellung und deren Verwendung

DE 19746008 A UPAB: 19990609 NOVELTY - A sintering additive- and SiO2-containing silicon nitride material has an extremely high grain boundary SiO2 content and a low oxynitride content. DETAILED DESCRIPTION - In a sintering additive- and SiO2-containing silicon nitride material, the molar ratio of the SiO2 in the grain boundary phase to the sintering additive including SiO2 in the grain boundary phase is greater than 60 % and the oxynitride content is less than 1 %. An INDEPENDENT CLAIM is also included for a process for producing the above silicon nitride material, in which (a) the Si3N4 powder is thermally oxidized alone or together with the sintering additive; (b) the Si3N4 powder is tribo-oxidized, alone or together with the sintering additive and optionally further additives, during grinding; and/or (c) the Si3N4 powder is reacted with a SiO2-forming component or SiO2 before or during grinding with the sintering additive. USE - In machine and appliance construction, especially in bearings (claimed). ADVANTAGE - The silicon nitride material has high corrosion resistance, e.g. exhibits low weight change and strength loss after acid treatment