ISSN:
1573-4803
Source:
Springer Online Journal Archives 1860-2000
Topics:
Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
Notes:
Abstract Silicon oxynitride ceramics are formed by reaction sintering of silicon nitride and silica with certain metal oxide additives. The reaction rate during sintering and the subsequent properties of silicon oxynitride are affected by the quantity and kinds of additives. The reaction rate increased for addition of equal molar amounts of ZrO2, ZrO2 (+2.8 mol % Y2O3), AlO1.5, LnO1.5, CeO2, MgO, in that order (where Ln=Nd, Sm, Gd, Dy, Er, Yb and Y). The lanthanide oxide (1.5 mol %)-doped silicon oxynitride ceramics had a high fracture toughness, because crack deflection occurred due to the precipitation of an intergranular crystalline phase with a high thermal expansion coefficient compared with silicon oxynitride. The oxidation rate was higher with an increasing quantity of additive. In samples containing an intergranular crystalline phase, stability of the crystalline phase is an important factor and could impair the oxidation resistance of silicon oxynitride ceramics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00545544
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