Authors: Wei Wan Chune Huang Jian Yang Jinzhen Zeng Tai Qiu
Publish Date: 2014/04/01
Volume: 43, Issue: 7, Pages: 2566-2572
Abstract
Fused silica ceramics were fabricated by gelcasting by use of a lowtoxicity N′Ndimethylacrylamide gel system and had excellent properties compared with those obtained by use of the lowtoxicity 2hydroxyethyl methacrylate and toxic acrylamide systems The effect of sintering temperature on the microstructure mechanical and dielectric properties and thermal shock resistance of the fused silica ceramics was investigated The results showed that sintering temperature has a critical effect Use of an appropriate sintering temperature will promote densification and improve the strength thermal shock resistance and dielectric properties of fused silica ceramics However excessively high sintering temperature will greatly facilitate crystallization of amorphous silica and result in more cristobalite in the sample which will cause deterioration of these properties Fused silica ceramics sintered at 1275°C have the maximum flexural strength as high as 8132 MPa but simultaneously a high coefficient of linear expansion 256 × 10−6/K at 800°C and dramatically reduced residual flexural strength after thermal shock 600°C Fused silica ceramics sintered at 1250°C have excellent properties relatively high and similar flexural strength before 6743 MPa and after thermal shock 6545 MPa a dielectric constant of 334 and the lowest dielectric loss of 120 × 10−3 at 1 MHz
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