用电导法测定镍合金中的镍

提出用丁二酮肟乙醇溶液滴定、电导法确定终点测定镍合金中镍的新方法。在氨性溶液中滴定，铜（Ⅱ）、锰（Ⅱ）、钴（Ⅱ）的干扰通过掩蔽或氧化的方法消除，其它金属离子对测定没有干扰。本方法不受溶液颜色和浊度的影响，试剂用量少，具有准确、快速、干扰少的特点，已用于镍合金中镍的测定，获得了精密度高、准确度好的分析结果。     

Embedded atom method calculations of vibrational thermodynamic properties of ordered and disordered Ni3Al

Recent work had suggested that vibrational effects can play a significant role in determining alloy phase equilibria. In order to better understand these effects, we investigate the vibrational properties of disordered and ordered Ni₃Al using the embedded atom method and calculate vibrational thermodynamic quantities within the quasi-harmonic approximation. The vibrational entropy is found to be strongly dependent on volume. For fully relaxed structures the dependence on lattice decoration of the vibrational entropy is compared to that suggested by recent experimental results.     

Pre-bainitic Transformation in Fe-Ni Alloy

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氢对18－8型奥氏体不锈钢焊缝金属力学性能与组织的影响

考察了高压气相热充氢对１８Ｃｒ－８Ｎｉ型奥氏体焊缝金属的力学性能与微观组织的影响。定量测试结果表明，充氢后焊缝金属的塑性明显降低，而强度变化不大；氢抑制了α＇马氏体的生成，由此否定了氢致α＇马氏体转变导致氢脆的观点。     

稀土对WC－8Ni硬质合金性能影响的研究

研究了添加微量稀土氧化物对ＷＣ－８Ｎｉ硬质合金物理机械性能的影响。在用Ｘ射线。射、扫描电镜及透射电镜等手段对含稀土ＷＣ－８Ｎｉ合金进行显微结构分析的基础上，探讨了稀土在合金中的分布状态、对组织结构的影响及其强化机理。井指出，通过添加微量稀土氧化物，可使ＷＣ－８Ｎｉ硬质合金的物理机械性能接近和达到ＹＧ８的水平。     

Effect of carbon on cavity formation during the high-temperature oxidation of Ni

Ni containing 0.00002 to 0.003 wt.% carbon was oxidized in 1 atm O₂ at 700 to 1270°C for 1 min to 20 hr. Cavity formation in the metal and oxide and at the oxide-metal interface was affected by the carbon content. Extensive cavitation developed at the grain boundaries of Ni containing as little as 0.0001 wt.% carbon but no cavitation occurred in decarburized Ni. Metal cavitation is dependent on the local concentration of carbon segregated at the Ni grain boundaries rather than on the overall carbon content. The cavities arise from hot deformation or creep of the metal substrate induced by the oxidation process. The cavities in the oxide formed on decarburized Ni remain near the oxide-metal interface; on Ni containing appreciable carbon the oxide cavities migrate outward by a dissociative mechanism assisted by the gaseous transfer of oxygen across the cavities with CO-CO₂ acting as the carrier.     

Ni/Si体系离子束混合及相变研究

注入参量变化引起不同的混合结果,在宽温区中得到Ni_2Si、NiSi、NiSi_2多种化合物相,进而探讨了Xe离子诱导的Ni/Si体系界面原子混合机理及诱发相变的动力学过程。     

Effects of contact metals on minority carrier diffusion lengths in GaAs

Contact technology for GaAs involves optimizing such factors as contact resistance or Schottky barrier height, alloy cycle conditions, thermal ageing, adhesion, and ease of high resolution processing. Minority carrier properties may be significantly degraded by in-diffusing contact metals. At typical alloying conditions of 10 sec at 500° C, Ni diffuses at least 10 μm and reduces the hole diffusion length (L_p) in vapor phase epitaxial GaAs from 4.4 to 1.7 ym. At 600°C, L_p becomes 1.0 μm. Other metals, such as Fe, Pt, and Cr, significantly improve L_p in VPE GaAs. L_p increases from 3.0 to 5.0 μm for an Fe diffusion of 5 minutes at 500°C. These improvements may be due to interaction of in-diffused Fe with recombination centers, such as Ga vacancy complexes or Ni. Fe causes increases in minority carrier diffusion lengths also in n and p type ingot GaAs, though 800 – 900°C diffusions are required and at these temperatures the doping is significantly changed by Fe acceptors.     

Comparative study of the activity of cobalt and nickel as promoters of HDS catalysts

A series of trimetallic (NiCoMo) hydrodesulphurisation supported catalysts were prepared using a successive impregnation method, varying the ratio of promoters Ni/(Ni + Co) and maintaining the ratio (Ni + Co)/Mo constant. Optima for higher thiophene hydrodesulphurisation activity were found for ratios Ni/(Ni + Co) of 0.7 and 0.8. It is suggested that the optima may be strongly dependent on method of catalyst preparation, and/or type of support employed. Presulphidation was found to increase the activity in NiMo more than in CoMo. Testing of commercial catalysts confirmed various differences between CoMo and NiMo catalysts.     

COMPETING REACTIONS OF EXISTING Ni SILICIDE AND Ni OR Si INDUCED BY THERMAL ANNEALING AND MeV Si ION BEAM MIXING

The competing reactions between existing Ni silicides surrounded by Si and Ni were investigated by thermal annealing and MeV Si ion beam mixing. With high energy irradiation, the energy deposition at both interfaces, Ni/Ni silicide and Ni silicide/Si, is equal. Two MeV He~- RBS and TEM were used to obtain the reacted layer composition and epitaxial orientation, respectively. Also glancing angle Co K_a. X-ray diffraction was utilized to identify phase formation. The main results indicate that the existing silicides preferentially react with Ni layer, and that there are pronounced differences of Ni silicide phase transition between thermal annealing and MeV Si ion beam mixing, even though the mixing was performed in radiation enhanced diffusion regime. The results can be explained in term of the heat of silicide formation and surface energy change.