Preparation of ZrW2O8 / ZrO2 composites with controllable thermal expansion
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摘要: 采用分步加热固相法成功制备了纯度较高的各向同性负热膨胀材料ZrW2O8 。将ZrW2O8 与ZrO2 按一定比例混合, 在1200 ℃烧结24 h 制备了热膨胀系数可控的ZrW2O8 / ZrO2 复合材料。研究结果表明, 通过改变ZrW2O8 的体积分数, ZrW2O8 / ZrO2 复合材料的热膨胀系数可以控制为负、正或零。当ZrW2O8 的体积分数为37 %时, 复合材料的热膨胀系数接近零。为了得到致密的ZrW2O8 / ZrO2 复合陶瓷, 采用Al2O3 作为烧结剂, 取得了较好的效果。0. 35 wt % Al2O3 的加入可以在不影响复合材料热膨胀性能的前提下, 显著提高复合材料的致密度。Abstract: ZrW2O8 which exhibit s excellent isot ropic negative thermal expansion was synthesized using the step bystep solid state reaction. The ZrW2O8 / ZrO2 composites with cont rollable thermal expansion coefficient were prepared by mixing ZrW2O8 and ZrO2 at different volume ratios and sintered at 1200 ℃for 24 h. The thermal expansioncoefficient of ZrW2O8 / ZrO2 composites can be cont rolled , being negative , positive or even zero , by adjusting the volume fraction of ZrW2O8 . The ZrW2O8 / ZrO2 composites show almost zero thermal expansion when the volume f rac2tion of ZrW2O8 is 37 %. In order to obtain dense and tough ZrW2O8 / ZrO2 ceramic , Al2O3 was adopted as an additive. The result s reveal that it is effective to improve the density of the composites. 0. 35 wt % Al2O3 additive canincrease the density of the composites rapidly with slight effect s on the thermal expansion property.
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Key words:
- controllable thermal expansion /
- negative thermal expansion /
- ZrW2O8 /
- composites /
- ZrO2
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