RHOMBOHEDRAL PHASE PRODUCED IN ABRADED SURFACES OF PARTIALLY STABILIZED ZIRCONIA (PSZ)
RHOMBOHEDRAL PHASE PRODUCED IN ABRADED SURFACES OF PARTIALLY STABILIZED ZIRCONIA (PSZ)
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DOI：
10.1007/bf00722220
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发表时间：
1983-01-01
期刊：
影响因子：
--
通讯作者：
HASEGAWA, H
中科院分区：
文献类型：
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作者：
HASEGAWA, H
在部分稳定氧化锆（PSZ）中，四方相在应力作用下容易转变为单斜相。G~ trvie et al.[1]和Gupta et al.[2]对含有大量四方相的PSZ进行了x射线衍射研究，证实了四方相向单斜相的转变发生在金刚石磨削过程中。Porter和Heuer[3]观察到，在裂纹尖端附近的应力作用下，正常PSZ中的四边形氧化锆沉淀由立方基体转变为单斜结构。然而，对于正常PSZ中立方氧化锆的相变研究却很少。本文研究了应力对含有充足溶质稳定剂的立方氧化锆相变的影响。将商品二氧化锆、氧化钇和一些促进烧结的添加剂的混合物压成直径15mm × 3ram的圆盘，煅烧，然后在1670℃的空气中烧结4h。这些样品的化学分析结果见表1，以及用x射线衍射技术检测到的物相。如表1所示，在部分试样中观察到a-A1203和/或/3-SIO2。残余的A1203和SiO2被认为在晶界中以玻璃相的形式存在。将试样置于不同的应力状态下，如SiC磨纸抛光、金刚石研磨等。用CoKc~辐射为40 kV、80 mA的x射线衍射仪检测了SiC砂纸抛光和金刚石砂轮磨削前后表层晶体结构的变化。抛光形成的表面层的晶体结构与纸上磨料粉的粗糙度密切相关。本文主要研究了表面粗糙度约为2~ m的最严格抛光试样
In partially stabilized zirconia (PSZ), the tetragonal phase transforms readily to monoclinic under the influence of stress. From X-ray diffraction studies of PSZ having a large amount of tetragonal phase, G~ trvie et al.[1] and Gupta et al.[2] confirmed that the transformation from tetragonal to monoclinic occurs by diamond grinding. Porter and Heuer [3] observed that the tetragonal zirconia precipitates in the normal PSZ with a cubic matrix change to the monoclinic structure under stress in the neighbourhood of a crack tip. However, the phase transformation of the cubic zirconia in normal PSZ seems to have been little studied. The present study is concerned with the effect of stress on the phase transformation of cubic zirconia containing sufficient solute stabilizer. A mixture of commercial zirconium dioxide, yttrium oxide and some additives to promote sintering was pressed into a disc of 15mm diameter x 3ram, calcined and then sintered at 1670 C for 4h in air. The chemical analysis of such specimens is given in Table I, together with the phases detected by X-ray diffraction technique. As shown in Table I, a-A1203 and/or/3-SIO2 are observed in some specimens. The remainders of A1203 and SiO2 are thought to be present as glassy phases in grain boundaries. The specimens were submitted to various stress states, such as polishing with SiC abrasive paper, diamond grinding and so on. The change of the crystal structure in the surface layer before and after polishing by SiC abrasive paper as well as grinding by the diamond wheel was examined by an X-ray diffractometer with CoKc~ radiation at 40 kV and 80 mA. The crystal structure of the surface layer formed by polishing is closely related to the roughness of the abrasive powder on the paper. Specimens submitted to the severest polishing, in which the roughness of the surface was of approximately 2~ m, were mainly studied in this