Press-Free Preparation Method of Dense Negative-Thermal-Expansion Oxide, Zr1-xYxW2O8-δ(x=0.00-0.02) Ceramic Using Reactive
Press-Free Preparation Method of Dense Negative-Thermal-Expansion Oxide, Zr1-xYxW2O8-δ(x=0.00-0.02) Ceramic Using Reactive
复制标题
反应型致密负热膨胀氧化物Zr1-xYxW2O8-δ(x=0.00-0.02)陶瓷的免压制备方法
DOI：
10.2109/jcersj.110.807
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发表时间：
2002
影响因子：
1.1
通讯作者：
T. Hashimoto
中科院分区：
文献类型：
--
作者：
Y. Morito;Kohji Takahashi;Shaorong Wang;H. Abe;Atsushi Katoh;T. Hashimoto
通过对ZrO_2、Y_2O_3和WO_3的混合粉末（其粒度分布为10-50μ m，为亚微米级）进行反应烧结，制备了具有负热膨胀系数的大块致密Zr_1-xY_xW_2O_（8-δ）氧化物。通过这种无压工艺制备的烧结样品的密度与通过包括模制/压制的工艺制备的类似材料的密度相当。结果表明，Y ~（3+）部分取代Zr ~（4+）能有效地促进晶粒长大，提高致密度。烧结体的密度为-96%，为上、下直径分别为-40 mm、-45 mm和20- 25 mm的截锥形。在所有的Zr_（1-x）Y_xW_2 O_（8-δ）（x=0.00-0.02）样品中均观察到负的热膨胀系数，该系数几乎不受Y ~（3+）含量的影响。实验还发现，以粒径分布为亚微米级的混合物为原料，只能制备出多孔且易碎的试样。这是由于形成的二阶颗粒，往往不会烧结在较大的颗粒。
By performing reactive sintering of a powder mixture of ZrO2, Y2O3 and WO3 (whose particle size distribution was 10-50μ and of submicron-order), large pieces of dense Zr1-xYxW2O8-δ oxide with a negative thermal expansion coefficient were prepared. The density of the sintered specimens prepared by such a press-free process was comparable with that of similar materials prepared by processes that include molding/pressing. It was found that the partial substitution of Y3+ for Zr4+ was effective for promoting grain growth, resulting in an increase of density. Zr0.98Y0.02W2O8-δ sintered bodies with density of -96% of a truncated cone shape with upper diameter, lower diameter and height of -40mm, -45mm and 20-25mm, respectively, were obtained. Negative thermal expansion was observed in all Zr1-xYxW2O8-δ specimens (x=0.00-0.02), this coefficient being hardly affected by the Y3+ content. It was also found that only porous and fragile specimens could be prepared by using a mixture with particle size distribution of submicron order as the raw material. This was ascribed to the formation of second-order particles that tended not to sinter within larger particles.