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Study on the Production of extra-low-oxygen titanium by Calcium -halide flux method

卤化钙熔剂法生产超低氧钛的研究

基本信息

批准号：
03453062
负责人：
ONO Katsutoshi
金额：
$ 4.35万
依托单位：
KYOTO 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：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

Under co-existence of calcium and its oxide, the equiliblium oxygen content in titanium is 500 mass ppmO at 1273K^<1)2)>. The advanced methods were examined to attain the lower oxygen level from the thermodynamic viewpoints. Calcium-halide fluxes may decrease the activity of by-product CaO so efficiently that Ca-CaCl_2 and Ca-BaCl_2 fluxes were experimentally applied for the deoxidation of titanium.Titanium wires and small pieces containing a few hundreds mass ppm were deoxidized as low as a few tens mass ppm by use of CaCl_2 flux and calcium vapor at 1273K. The oxygen sources to make worse the efficiency of the further purification of titanium were discussed and one of them was suggested to be the oxygen contamination in the flux.Deoxidation of high purity titanium using an electrochemical technique and characterization of the obtained nearly oxygen-free titanium were carried out. High purity titanium cathode and carbon anode were immersed in molten salt (e.g. CaCl_2) at around 1223 K, and external DC voltages were applied between the electrodes. High purity titanium cathode wires containing 110 mass ppmO were deoxidized to less than 20 ppm. Trace element analysis(e.g. glow discharge mass spectrometry), micro Vickers hardness measurements, and electrical resistivity measurements were carried out to characterize the deoxidized titanium samples. The electrochemical deoxidation produced high purity titanium with a high residual resistivity ratio (rho_<298>/rho_<4.2>=155) and a low micro Vickers hardness value (64kgf/mm^2). Feasibility of deoxidation by using various molten salts such as BaCl_2 and MgCl_2 was also examined, and titanium containing about a thousand mass ppm oxygen were deoxidized to 100 - 300 ppm level by using these salts.

在钙及其氧化物共存的情况下，在1273 K ^<1）2）>下，钛中的平衡氧含量为500质量ppmO。从热力学的角度考察了获得低氧水平的先进方法。钙卤化物助熔剂能有效地降低副产物CaO的活性，因此，在1273 K下，采用Ca-CaCl_2和Ca-BaCl_2助熔剂对钛进行脱氧，对质量分数为几百ppm的钛丝和钛片进行了脱氧，脱氧温度低至几十ppm。讨论了影响纯钛提纯效果的氧源，认为熔剂中的氧污染是影响钛提纯效果的氧源之一，采用电化学方法对高纯钛进行脱氧，并对获得的近无氧钛进行了表征。将高纯钛阴极和碳阳极浸入1223 K左右的熔融盐（如CaCl_2）中，并在电极之间施加外直流电压。将含有110质量ppm O的高纯钛阴极丝脱氧至小于20 ppm。微量元素分析（例如辉光放电质谱法），显微维氏硬度测量，和电阻率测量进行表征脱氧钛样品。电化学脱氧可获得高残余电阻率比（rho_<298>/rho_<4.2>=155）和低显微维氏硬度（64 kgf/mm^2）的高纯钛。还考察了用各种熔盐如BaCl_2和MgCl_2进行脱氧的可行性，用这些熔盐将含约1000质量ppm氧的钛脱氧到100 - 300 ppm水平。