Effect of grain size on the monoclinic transformation, hardness, roughness, and modulus of aged partially stabilized zirconia
Effect of grain size on the monoclinic transformation, hardness, roughness, and modulus of aged partially stabilized zirconia
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DOI：
10.1016/j.dental.2015.09.014
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发表时间：
2015-12-01
期刊：
影响因子：
5
通讯作者：
Burgess, John O.
中科院分区：
文献类型：
--
作者：
Lucas, Thomas J.;Lawson, Nathaniel C.;Burgess, John O.
目标。据报道，低温降解(LTD)会导致Y-TZP多晶的性能发生变化。本研究测量了不同晶粒度的Y-TZP的单斜晶型相变以及相应的人工老化引起的性能变化。零假设：陈化Y-TZP的颗粒大小不会影响其转化率、粗糙度、硬度和弹性模数。共观察了4组不同粒度的Y-TZP(n=5)。用线截距技术测定了扫描电子显微镜图像(100,000x)上的晶粒度。人工老化是在2bar压力下高压灭菌5h完成的。用X射线衍射仪(30 mA，40千伏)测量了四方相变(t>；m)。使用非接触式表面轮廓仪进行表面粗糙度分析。采用纳米压痕技术测量了纳米材料的硬度和弹性模量。扫描电子显微镜分析表明，每个样品组的颗粒大小不同(0.350微米、0.372微米、0.428微米和0.574微米)。随着颗粒尺寸的增大，t-gt；m相变的比例增加；此外，氧化锆的老化导致粗糙度增加。时效后的弹性模数和硬度与晶粒度之间没有显著的相关性或交互作用。较小的晶粒导致较少的相变，时效导致粗糙度增加，但晶粒度不影响表面粗糙度的增加量。还需要进一步的研究来确定颗粒大小对牙科氧化锆磨损和断裂性能的影响。(C)2015年牙科材料学会。爱思唯尔有限公司出版。保留所有权利。
Objective. Low-temperature-degradation (LTD) has been reported to cause property changes in yttria-tetragonal zirconia polycrystals (Y-TZP). The current study measured monoclinic phase transformation of Y-TZP with different grain sizes and corresponding property changes due to artificial aging. Null hypothesis: the grain size of aged Y-TZP will not influence its transformation, roughness, hardness or modulus of elasticity.Methods. Four groups of Y-TZP were examined with differing grain sizes (n=5). The line intercept technique was used to determine grain sizes on SEM images (100,000x). Artificial aging was accomplished by autoclaving at 2 bar pressure for 5h. X-ray diffraction (30 mA, 40 kV) was used to measure tetragonal to monoclinic transformation (t -> m). Surface roughness analysis was performed using a non-contact surface-profilometer. Nano-hardness and modulus of elasticity were measured using nano-indentation.Results. SEM analyses showed different grain sizes for each sample group (0.350 mu m, 0.372 mu m, 0.428 mu m, and 0.574 mu m). The fraction of t -> m transformation increased as grain size increased; furthermore, aging of zirconia caused increased roughness. Modulus and hardness after aging displayed no significant correlation or interaction with grain size.Significance. Smaller grains caused less transformation, and aging caused increased roughness, but grain size did not influence the amount of increased surface roughness. Future studies are needed to determine the effects of grain size on the wear and fracture properties of dental zirconia. (C) 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.