铁钛共掺强韧化蓝宝石晶体的研究

研究了铁钛共掺蓝宝石(Fe, Ti: Sapphire)晶体的常温力学性能. 采用泡生法技术生长了尺寸为ø180 × 280 mm³质量为30 kg的 Fe, Ti: Sapphire晶体. 实验发现, 在蓝宝石晶体中掺入Fe₂O₃和TiO₂以及相应的热处理可以显著提高晶体常温断裂强度、表面硬度和断裂韧性, 而不损害晶体的可见和近红外透过性能; 掺入的Fe₂O₃其Fe³⁺对Al³⁺ 的取代作用导致晶体内应力的增加, 掺入的TiO₂其Ti⁴⁺ 热处理时结晶出的第二相针状晶体的韧化效应, 均对Fe, Ti: Sapphire晶体的力学性能的提高具有重要作用. 研究对我国实现高强蓝宝石晶体应用材料具有重要现实意义.关键词：蓝宝石晶体力学性能铁钛共掺热处理

A method to strengthen and toughen Sapphire by codoping of Fe/Ti ions

Mechanical properties of titanium and iron co-doped Sapphire crystal are first studied at room temperature Large (ø180 × 280 mm³ in dimension 30 kg in weight) titanium and iron codoped sapphire single crystal is grown by the Kyropoulos technique It is shown that the fracture strength and surface hardness and fracture toughness of as-grown crystals are significantly improved and the visible-infrared optical property is not adversely affected by titanium and iron codoping and certain heat treatment. The Fe³⁺ in the doped Fe₂O₃ palys a role of substituting Al³⁺, leading to an in creased internal stress in the crystal. And the Ti⁴⁺ in the doped TiO₂ crystallizes the second phase needle crystal and brings in a toughening effect through certain heat treatment. As a consequence, the mechanical properties of as-grown sapphire are improved at room temperature. The present work has the realistic significance for developing the sapphires of excellent mechanical properties.