Effect of chemical composition on the optical properties and fracture toughness of transparent magnesium aluminate spinel ceramics
Effect of chemical composition on the optical properties and fracture toughness of transparent magnesium aluminate spinel ceramics
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DOI：
10.2320/matertrans.46.996
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发表时间：
2005-05-01
影响因子：
1.2
通讯作者：
Kagawa, Y
中科院分区：
文献类型：
--
作者：
Dericioglu, AF;Boccaccini, AR;Kagawa, Y
以市购MgO和Al2O3粉末为原料，采用热压和热等静压法制备了透明铝酸镁“尖晶石”陶瓷。spinet的Al2O3含量发生了系统的变化，可以用MgO表示。nAl(2)O(3), n = 1.0, 1.5, 2.0。紫外/可见光和近红外波长区域的光反射和透射行为与spinet陶瓷的微观结构定量相关，以解释制备材料的光学质量。当n = 1.0时，由于微裂纹晶界处明显的光散射，化学测量spininet陶瓷的光学透明度相对较差，在可见波长范围内的镜面透光率约为20-40%。另一方面，富含Al2O3的组分在相同波长范围内的镜面透射率为-40-60%，透明度高。此外，采用压痕和凹痕试样断裂韧性测量技术，研究了化学成分对spinet陶瓷断裂韧性的影响。当n = 2.0时，spinet陶瓷的断裂韧性最高，平均值约为2.02 MPa-m（1/2）。基于其光学和力学性能，指出了富Al2O3非化学计量多晶spinet陶瓷在高光学透明度和提高断裂韧性的工程应用中的潜力。
Polycrystalline transparent magnesium aluminate "spinel" ceramics were fabricated by hot-pressing and hot isostatic pressing (HIPing) using commercially available MgO and Al2O3 Powders. Al2O3 content of spinet was systematically changed that can be expressed as MgO.nAl(2)O(3) with n = 1.0, 1.5 and 2.0. UV/visible and near-IR wavelength region light reflection and transmission behaviors of the spinet ceramics were quantitatively correlated to their microstructure to account for the optical quality of the fabricated materials. The stoichiometric spinet ceramic with n = 1.0 revealed a relatively poor optical transparency due to pronounced light scattering at the microcracked grain boundaries with a specular light transmission of similar to 20-40% in the visible wavelength range. On the other hand, Al2O3 rich compositions revealed a specular transmission of -40-60% in the same wavelength range with a high degree of transparency. Additionally, effect of chemical composition on the fracture toughness of spinet ceramics was investigated applying indentation and chevron notched specimen fracture toughness measurement techniques. The spinet ceramic with n = 2.0 revealed the highest fracture toughness with a mean value of similar to 2.02 MPa-m(1/2). Based on their optical and mechanical properties, potential of Al2O3 rich non-stoichiometric polycrystalline spinet ceramics for engineering applications requiring high optical transparency and improved fracture toughness was addressed.