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在850—1050℃含有Ta或Nb离子的氟化物熔盐中,用电化学表面合金化的方法制备了Ta-Ni和Nb-Ni二元合金,分析表明合金层的成分是均匀的TaNi_3和NbNi_3化合物.利用恒电流间隙滴定技术(Galvanostatic Intermittent Titration Technique)证实了Ta-Ni二元系存在Ta_2Ni,TaNi,TaNi_2和TaNi_3四种化合物,测定了其生成电位和自由能;Nb-Ni二元系仅生成、NbNi和NbNi_3二种化合物.在熔盐电化学表面合金化的过程中,表面合金层的厚度与时间呈抛物线关系.测定了Ta-Ni和Nb-Ni合金中Ta和Nb的扩散系数,并建立了扩散系数随温度变化的Arrhenius方程
Ta-Ni and Nb-Ni binary alloys were prepared by electrochemical surface alloying in the molten salt of fluoride containing Ta or Nb ions at 850-1050 ℃. The results show that the composition of the alloy layer is uniform TaNi 3 and NbNi 3 Compounds.The four compounds of Ta_2Ni, TaNi, TaNi_2 and TaNi_3 were confirmed by Galvanostatic Intermittent Titration Technique and their potential and free energy were measured. The Nb-Ni binary system NbNi and NbNi_3 compounds were synthesized.The electrochemical properties of Ta-Nb and Nb-Ni alloys were investigated by means of a parabolic relationship between the thickness of the surface alloy layer and the time during the electrochemical alloying of molten salt.The diffusion coefficients of Ta and Nb in Ta-Ni and Nb-Ni alloys were measured, The Arrhenius equation of diffusion coefficient with temperature is established