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 A monolithic type of toughened silicon nitride ceramics has been developed from Si3N4-Y2O3 systems. However, because of the existence of a second phase, the fracture strength decreases at elevated temperatures. To improve the high-temperature strength of silicon nitride, some additional components were investigated. It was found that the addition of hafnia to the Si3N4-Y2O3-AIN system gave a greater high-temperature strength based on the promotion of grain-boundary phase crystallization: namely, 126 kg mm−2 in 3-point bend strength at 1300 °C for the hot-pressed specimen, and 90 kg mm−2 at 1300 °C for the pressureless sintered specimen. The role of the hafnia in crystallization is not yet clear, and is being characterized by electron microscopy and microanalysis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02403951
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