Processing of nanocrystalline 8 mol% yttria-stabilized zirconia by conventional, microwave-assisted and two-step sintering
Processing of nanocrystalline 8 mol% yttria-stabilized zirconia by conventional, microwave-assisted and two-step sintering
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DOI：
10.1016/j.msea.2008.03.023
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发表时间：
2008-09
期刊：
影响因子：
6.4
通讯作者：
M. Mazaheri;A. Zahedi;M. Hejazi
中科院分区：
文献类型：
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作者：
M. Mazaheri;A. Zahedi;M. Hejazi
使用常规烧结（CS）、两步烧结（TSS）和微波辅助烧结方法来制造接近全致密（>97%）的8mol%氧化钇稳定的氧化锆（8 YSZ）纳米粉末（15- 33 nm）压坯。微波烧制通过两种不同的加热速率进行，即5和50°Cmin-1。尽管发现较低速率的微波烧结（LMS）在较低温度下产生较高的密度，但是与其他方法相比，该方案最终没有提供更高的最终密度。另一方面，较高速率的微波烧结（HMS）设法抑制了加速的晶粒生长，并导致比LMS（2.35μm）和CS（2.14μm）更细的显微组织（0.9μm）。尽管TSS法在制备超细晶（0.29μm）样品方面具有很强的能力，但显微组织的不均匀性和总烧结时间（> 20 h）（与HMS法（29 min）相比）限制了TSS法的应用。根据晶粒尺寸对陶瓷力学性能的影响，TSS法制备的陶瓷样品的断裂韧性（3.16± 0.06MPam 1/2）高于CS法（1.61± 0.07MPam 1/2）和LMS法（1.9± 0.09MPam 1/2），这是由于TSS法制备的陶瓷样品晶粒尺寸较细所致。TSS和HMS试样的断裂韧性值（3.17±0.10MPam1/2）接近，这是由于HMS试样具有较大的晶粒尺寸，但组织均匀性较高。
Manufacturing of near full dense (>97%) 8mol% yttria-stabilized zirconia (8YSZ) nanopowder (15–33nm) compacts was manipulated using conventional sintering (CS), two-step sintering (TSS) and microwave-assisted sintering methods. Microwave firing was performed via two different heating rates, i.e. 5 and 50°Cmin−1. Although, the lower rate microwave sintering (LMS) was found to yield the higher densities at lower temperatures, this regime ultimately did not provide higher final densities compared to the other methods. The higher rate microwave sintering (HMS) on the other hand managed to suppress the accelerated grain growth and resulted to a finer microstructure (0.9μm) than LMS (2.35μm) and CS (2.14μm). In spite of the great capability of TSS method in fabricating the specimens with ultra-fine grains (0.29μm), microstructural inhomogeneity and the long total sintering time (>20h) in comparison with HMS (29min) set restrictions on the application of TSS method. Based on the effect of grain size on the mechanical properties of ceramics, the specimens produced by TSS exhibited higher fracture toughness (3.16±0.06MPam1/2) than those obtained from CS (1.61±0.07MPam1/2) and LMS (1.9±0.09MPam1/2), due to their finer grain size. The proximity in the fracture toughness values of TSS and HMS (3.17±0.10MPam1/2) samples stems from the higher microstructural homogeneity caused by HMS, while having a larger grain size.