科研之友
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摘要
Polymer-derived SiOC ceramics were prepared by field-assisted sintering at 1600 degrees C. In order to characterize this material, X-ray diffractometry, density measurements, and mechanical tests were performed. It was determined that the material is dense and predominantly amorphous with fine crystalline regions of beta-SiC. A fracture toughness of 0.84 MPa center dot m1/2 was determined from single edge, v-notched bending tests. Inert strength and subcritical crack growth parameters were derived from the ball-on-three-balls tests carried out at different loading rates. The inert strength of 212 MPa and the crack growth exponent n of 15 are on a similar level as commonly expected for silica-based glasses. Because of an enhanced crack growth parameter A(0), the crack velocity of the SiOC material at a given stress intensity level is significantly reduced compared with silica glasses.
- 出版日期2010-6
