In this work, a small amount of CaO single dopant was adopted to realize the densification and microstructure control of fine grained YAG ceramic with excellent optical quality, by a simple solid-state reaction and one-step vacuum sintering method. Then, highly transparent YAG ceramics (T = 84.4% at 1064 nm) were obtained just after vacuum sintering at 1820°C for 8 hours. The average grain size was only 2.7 μm, when the total amount of CaO was as low as 0.045 wt%. The effect of CaO on the microstructural evolution and optical property of the as-fabricated YAG ceramics was systematically investigated in detail. It was found that CaO dopant promoted both densification and grain growth of YAG ceramics when the sintering temperature was lower than 1660°C, however, it dramatically inhibited grain growth when the sintering temperature was further increased.

中文翻译：

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单CaO加速高透明YAG陶瓷致密化及微观结构控制

在这项工作中，通过简单的固相反应和一步真空烧结的方法，采用少量的 CaO 单一掺杂剂来实现具有优异光学质量的细晶粒 YAG 陶瓷的致密化和微观结构控制。然后，在 1820°C 下真空烧结 8 小时后，立即获得高度透明的 YAG 陶瓷（T = 84.4% 在 1064 nm）。当 CaO 的总量低至 0.045 wt% 时，平均晶粒尺寸仅为 2.7 μm。详细系统地研究了 CaO 对制造的 YAG 陶瓷的微观结构演变和光学性能的影响。发现当烧结温度低于 1660°C 时，CaO 掺杂剂促进了 YAG 陶瓷的致密化和晶粒生长，然而，