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Study of Super Refractory Zirconia Investments for Titanium Casting

钛铸件用超耐火氧化锆包埋材料的研究

基本信息

批准号：
01460240
负责人：
WATARI Fumio
金额：
$ 0.32万
依托单位：
Tokyo Medical and Dental University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1990
项目状态：
已结题

项目摘要

Titanium, one of the most ideal materials for dental use from the aspects of corrosion resistance, bio-compatibility, light specific gravity, economical cost, was difficult to apply for casting with the conventional silica investments because of the high reactivity at high temperature. This study for the first part investigated the reactivity of the metal of molten titanium with ceramics and that with gas to obtain the principle of reactivity and the basis to select materials in developing the new refractory investments. Based on these fundamental studies, the newly developed zirconia investments could produce the bright castings of titanium. The method of the heat treatment to strengthen titanium was also studied. The principal accomplishments were as follows : (1) From the experiments of the reaction between the single crystal ceramics and molten titanium, it was shown that the alkaline (basic) tendency of oxides as well as formation energy are important factors in the reactivity cha … More racteristics. (2) In this viewpoint, the oxide matrix refractory to the highly reactive metal was selected and super refractory zirconia investments were newly developed. (3) The decomposition behavior of gypsum used as a binder for conventional investments was also found to depend on the alkaline tendency of the matrix oxide. (4) As a new material for implants and bio-materials used in the human organization, titanium/apatite composite sintered materials and functionally gradient materials (FGM) are now under development, in which process the reactivity tendency was applied for the solution of the problems such as green setting, sintering, suppression of oxidation and enhancement of reduction. (5) In silica investments, the reaction with both ceramics and gas occurs simultaneously, whereas in non-reactive zirconia investments the reaction with gas is an independent process. Therefore, it is possible to strengthen titanium by heat treatment after casting. The methods of double step heat treatment and homogenizing anneal were developed to utilize solution hardening by interstitial alloying elements (oxygen, nitrogen, carbon). It can be applied for the surface hardening treatment and the control of elasticity of full denture. Less

钛具有耐腐蚀、生物相容性好、比重轻、成本经济等优点，是目前牙科应用中最理想的材料之一，但由于钛在高温下具有较高的反应性，难以用传统的二氧化硅熔模进行铸造。本研究第一部分研究了熔融钛金属与陶瓷的反应性和与气体的反应性，得出了反应性的原理和开发新型耐火材料时选择材料的依据。在这些基础研究的基础上，新开发的氧化锆熔模可以生产出光亮的钛铸件。研究了热处理强化钛的方法。主要研究成果如下：(1)从单晶陶瓷与熔融钛的反应实验中发现，氧化物的碱性倾向和形成能是影响单晶陶瓷反应性能的重要因素。(2)从这一观点出发，选择了对高活性金属耐火的氧化物基体，并对超耐火氧化锆投资进行了新开发。(3)作为常规投资粘合剂的石膏的分解行为也取决于基质氧化物的碱性倾向。(4)钛/磷灰石复合烧结材料和功能梯度材料（FGM）作为一种新型的植入材料和用于人体组织的生物材料正在开发中，其反应性倾向在工艺上被应用于解决绿色凝固、烧结、抑制氧化和增强还原等问题。(5)在二氧化硅投资中，与陶瓷和气体的反应同时发生，而在非反应性氧化锆投资中，与气体的反应是一个独立的过程。因此，铸造后通过热处理强化钛是可能的。采用双步热处理和均质退火的方法，利用间隙合金元素（氧、氮、碳）进行固溶硬化。可用于全口义齿的表面硬化处理和弹性控制。少