Development of Machinable Glass Ceramics Containing Rare Earth Oxides

可加工微晶玻璃被用作耐热材料、电绝缘材料、化学耐久材料等。可加工微晶玻璃通常含有云母，它具有很高的可解性，通过在玻璃中沉淀云母，通过烧结等方法获得。不幸的是，云母的这种固有特性也赋予了与普通玻璃相比降低的硬度和弹性模量。作者发现含有稀有金属氧化物的铝硅酸盐微晶玻璃具有良好的可加工性。本研究的目的是改善由于非碱性成分而产生的高硬度、高弹性模数和高电绝缘的微晶玻璃的可加工性。用普通熔融法制备了几个系列的含Y203铝硅酸盐玻璃，并对其维氏硬度、表面粗糙度等物理性能进行了测试。同时研究了替代碱土氧化物或各种稀土氧化物的玻璃的析晶行为。采用Sol-Gel工艺制备了这类可加工玻璃陶瓷。成功地对结晶样品进行了车削加工，并对其表面粗糙度进行了检测。较高的碱土氧化物引入量会导致表面粗糙度和晶化的硬度和/或体积分数之间的某种关联。

Machinable glass Ceramics, which can be cut, ground drilled and milled by equipment used for machining and fast -machining of metals, are being used as heat-resistant materials, electrical insulation, chemically durable materials etc. Usually, machinable glass-ceramics contain mica, which has high cleavability, obtained by precipitating mica in glass, by sintering etc. Unfortunately, this intrinsic property of mica also imparts reduced hardness and elastic modulus compared to ordinary glasses. Rare-metal oxide containing aluminosilicate glass ceramics were found to be good machinability by the authors. It is purposes of the present study to improve the machinabilty of the glass Ceramics of higher hardness and elastic modulus and higher electrical insulation because of nonalkaline composition. Several series of Y203-containing aluminosilicate glasses were prepapared by an ordinary melting method, and their physical properties, such as Vickers hardness, surface roughness and so forth. Crystalization behaviors were at the same time studied for the samples substituted for alakaline earth oxide or kinds of rearth earth oxides in theses glasses. Sol-gel process were adopted to make the machinable glass cermics of these kinds. Crystallized samples were successfullly lathed and their surface roughness was examined. Higher amounts of alkaline earth oxide introduction leads to some correlatation to the surface roughness and harness and/or volume fraction of cryatallization.