The wettability of Y–Al–Si–O–N oxynitride glasses and its application in silicon nitride joining

In the present work, first, the wettability of Y–Al–Si–O–N oxynitride glasses on Si3N4 substrates was investigated. It was found that the wettability of the glass depended on the ratios of Y2O3/Al2O3, i.e. when the ratio of Y2O3/Al2O3 increased, the wettability of corresponding glass on Si3N4 substrate improved. Based on the wettability work, Si3N4 ceramics can be successfully joined using glass with the best wettability. It was proved that a proper joining temperature is important for sound joints; a lower temperature would result in incomplete contact of the glass brazing layer with Si3N4 while a temperature higher than 1600° would cause separation of Si3N4 joints by complete drainage of brazing glass into bulk Si3N4 ceramics. In the range of experiment time, to prolong brazing time is of benefit to the shear strength.