Flash sintering of a three‐phase alumina, spinel, and yttria‐stabilized zirconia composite
Flash sintering of a three‐phase alumina, spinel, and yttria‐stabilized zirconia composite
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DOI：
10.1111/jace.14818
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发表时间：
2017-07
影响因子：
3.9
通讯作者：
David Kok;S. Jha;R. Raj;M. Mecartney
中科院分区：
文献类型：
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作者：
David Kok;S. Jha;R. Raj;M. Mecartney
在直流电场作用下，采用闪速烧结法制备了由等体积分数α-Al 2 O3、MgAl 2 O 4尖晶石和立方相8mol%Y2O3稳定的ZrO 2（8 YSZ）组成的三相陶瓷复合材料。使用恒定加热速率在50-500 V/cm的电场下测量快速致密化（快速烧结）开始的温度。通过以恒定速率加热炉来进行实验。闪速烧结在100 V/cm的电场下在1350°C的炉温下发生，其在500 V/cm的电场下降至1150°C。烧结密度范围为90%至96%。较高的电场抑制晶粒生长，由于闪速温度的降低和加速烧结速率。在闪速烧结过程中，氧化铝与尖晶石相反应，形成高铝尖晶石固溶体，通过电子色散光谱法和从减少的尖晶石晶格参数，如通过X射线衍射测量确定。提出了电场和焦耳加热相结合促进固溶反应的观点。
Three-phase ceramic composites constituted from equal volume fractions of α-Al2O3, MgAl2O4 spinel, and cubic 8 mol% Y2O3-stabilized ZrO2 (8YSZ) were flash-sintered under the influence of DC electric fields. The temperature for the onset of rapid densification (flash sintering) was measured using a constant heating rate at fields of 50-500 V/cm. The experiments were carried out by heating the furnace at a constant rate. Flash sintering occurred at a furnace temperature of 1350°C at a field of 100 V/cm, which dropped to 1150°C at a field of 500 V/cm. The sintered densities ranged from 90% to 96%. Higher electric fields inhibited grain growth due to the lowering of the flash temperature and an accelerated sintering rate. During flash sintering, alumina reacted with the spinel phase to form a high-alumina spinel solid solution, identified by electron dispersive spectroscopy and from a decrease in the spinel lattice parameter as measured by X-ray diffraction. It is proposed that the solid solution reaction was promoted by a combination of electrical field and Joule heating.