Ultra Precision Cutting of Steel by Oxide-Titanium Reinforced Sapphire Cutting Tool

在超精密加工中，除铁质材料外，工作材料仅为铜、铝及其合金，并采用精密技术研磨的单金刚石刀具。由于金刚石碳在工钢中的扩散使刀具磨损迅速加剧，单金刚石刀具无法对钢进行切削。然后，试制了白色蓝宝石（氧化铝单晶）刀具作为超精密刀具。而白色蓝宝石的硬度在2000HV左右，是金刚石硬度的四分之一。将固溶硬化技术应用于白色蓝宝石和氧化铝陶瓷材料的质量改进，将氧化铝和氧化钛混合粉末烧结而成。对蓝宝石和氧化铝陶瓷进行了摩擦磨损和抗冲击性能试验。两种测试材料都形成一个锥形。在摩擦试验中，试验锥的顶部压在旋转的圆柱形钢S55C上。在抗冲击试验中，S55C钢板被试验和平锥顶部划伤。将氧化钛封闭在氧化铝材料中的方法是将氧化铝样品放入氧化钛粉末中，在电炉中加热。在摩擦磨损试验和冲击划伤试验中，蓝宝石和陶瓷中添加氧化钛均提高了锥顶的耐磨性和抗脱落性。

On the ultra precision machining, the work materials are only copper, aluminum and their alloys except ferrous material, and the single diamond cutting tools lapped by the fine technology are employed. The steels are not able to be cut by the single diamond cutting tool, because the tool wear progressed rapidly by the diffusion of diamond carbon into work steel. Then, white sapphire (single crystal of aluminum oxide) cutting tools are made trial as the ultra precision cutting tool. But the hardness of white sapphire is about 2000HV, one quarter value of diamond hardness. The solid solution hardening is applied to the qualitative improvement of white sapphire, and alumina ceramics materials produced by sintering the powder mixed aluminum oxide and titanium oxide. These reinforced sapphires and alumina ceramics are experimented for the frictional wear and impact resistance. Both kinds of test materials are formed into a cone shape. On the frictional tests, the top of the test pesce cones are pressed on rotating cylindrical steel S55C. On the impact resistance tests, the steel S55C plate is scratched by the top of test peace cones. Titanium oxide is occluded in alumina materials by thermal diffusing addition method of which alumina sample is put into the titanium oxide powder and is heated in electric furnace. On the frictional wear tests and impact scratched tests, the sapphire and ceramics added titanium oxide increased the resistance for the wear and the breaking off of top of cone.