刘斌丛园张涛邵亚薇孟国哲王福会
腐蚀科学与防护技术
采用动电位极化、电化学阻抗和Mott-Schottky等电化学测试方法，研究了在室温、3.5% NaCl溶液条件下，静水压力对纯镍的钝化膜性能的影响。结果表明：随着静水压力的增加，纯镍的腐蚀速度增大，阴极过程保持不变，阳极过程加速。静水压力对阳极过程的影响:一方面提高纯镍钝化膜的抗腐蚀能力，使钝化膜中的受主密度减小，空间电荷层的厚度增加；另一方面，恶化了纯镍的钝化膜腐蚀抗腐蚀能力，使钝化膜变得不稳定，并且表现出较高的化学溶解速度和空穴扩散系数。静水压力对纯镍钝化膜的恶化作用比提高作用对阳极过程的影响更大，导致纯镍的抗腐蚀能力随着静水压力的提高而减小。
关键词:
静水压力
,
corrosion
,
nickel
,
deep ocean
,
passive film
李诗卓
,
姜晓霞
,
尹付成
,
M.B.Peterson
,
S.J.Calabrese
材料研究学报
用真空电弧炉熔制了六种成分的Ni-Cu-Re 合金,当Re 量(?)5at.-%时,除了Ni(Cu,Re)固溶相外还出现Re(Ni,Cu)相。用旋转式销盘高温摩擦试验机测定了这几种合金的摩擦系数随温度变化规律,证实高温摩擦系数降低至0.2—0.3。通过摩擦系数转变温度及磨损系数与Re 量关系找出了合金的合适含Re 量(7.5at.-%)。用SEM 观察了室温到700℃下的磨痕,确认了氧化膜层的减摩作用。
关键词:
摩擦
,
oxide film
,
rhenium
,
nickel
刘斌
,
张杰
,
张涛
,
邵亚薇
,
孟国哲
,
王福会
腐蚀科学与防护技术
利用电化学测量方法测量纯镍在3.5% NaCl溶液中,静水压力为0 MPa和8 MPa条件下的点蚀击破电位和孕育时间.分析得到纯镍在不同静水压力下点蚀击破电位的理论精确值,利用随机分析方法分析纯镍在静水压力下的点蚀机制.实验结果表明静水压力对纯镍的点蚀过程有着重要的影响,在静水压力下纯镍的点蚀行为和机制发生了改变.在较高的静水压力下,纯镍点蚀产生的敏感性增强,点蚀击破电位Ecritical明显降低；纯镍点蚀诱导时间也变短,其点蚀产生的机制发生了改变；在较高静水压力下,纯镍表面的钝化膜活性增强,恶化了纯镍的耐蚀能力.
关键词:
静水压力
,
nickel
,
deep ocean
,
itting
,
stochastic analysis
韩东生
,
荆天辅
,
乔桂英
,
周继锋
,
李季辉
中国腐蚀与防护学报
通过阴极极化曲线的测定研究了硫酸盐电解液喷射速度μ(流速）对电流密度jc和阴极过电位ηc的影响。结果表明，电流密度为140A/dm2时，喷射速度由0.83m/s增大到5.00m/s,阴极过电位从1.48V增到8.52V.与槽镀搅拌作用相比,电解液流速增大,有利于氢还原析出,导致过电位显著增大,随电流密度增大,阴极上析氢步骤逐渐取代水合镍离子电化学还原步骤成为整个过程的控制步骤,过电位可达12.03V
关键词:
喷射电沉积
,
nickel
,
overpotential
,
control steps
赵良仲
,
潘承璜
金属学报
用XPS研究了金属Ni在不同温度下在空气和水中的氧化行为及生成的表面氧化物的热稳定性。结果表明氧化物除NiO以外还存在Ni_2O_3。在室温下长期暴露空气后Ni表面生成Ni_2O_3更明显。金属Ni在纯水中氧化比空气中慢得多。研究结果还表明:Ni表面氧化物的热稳定性与其生成时的温度密切有关。金属Ni在室温暴露空气生成的NiO在10~(-6)Pa真空中在300℃加热10min即可使其还原成金属Ni。该还原作用是NiO与表面碳氢化合物污染物之间的反应。然而,在200℃以上在空气中加热生成的NiO在相同条件下作真空热处理时不能使其还原成金属。最后本文对不同温度下生成的NiO有不同的热稳定性的原因进行了讨论。
关键词:
X射线光电子能谱
,
nickel
,
surface oxides
,
thermal stability
Journal of Materials Science
The microstructure transitions during leaching of a rapidly solidified Ni-Al alloy have been investigated by means of X-ray diffraction, transmission electron microscopic (TEM) and high resolution electron microscopic (HREM) techniques. Ni2Al3 was the main phase in the starting Ni-Al alloy. The microstructure of the Raney nickel catalyst consists of nano-scale nickel crystallites, residue of source phases surrounded by nano-scale boundary regions. The transformation during leaching of Ni2Al3 phase was an advancing interface type process. Clusters of AuCu-structure type face-centrered tetragonal Ni3Al2 as an intermediate phase seems to appear in the reaction front. Based on an analysis of the atomic configurations of phases Ni2Al3, Ni3Al2 and nickel, a reasonable explanation for the transition mechanism during leaching of Ni2Al3 phase and the arc characteristic of diffraction spots was proposed. The nickel crystallites generated during leaching obey an orientation relationship with the source Ni2Al3 phase, which is consistent with the Delannay's orientation relationship proposed for nickel and NiAl phases. The nano-scale structural characteristic of the Raney nickel catalyst, especially its porous structure at the boundary regions, provides an excellent hydrogenation catalytic activity and selectivity of the catalyst. (C) 2001 Kluwer Academic Publishers.
关键词:
nickel
Materials Characterization
This paper describes work performed to determine some of the properties of the electroless Ni-W-P amorphous deposits. Phosphorus contents were varied up to 32 at.%, and the amorphous structure was found to be present at phosphorus contents above 5 at.%. Irrespective of P content, all the deposits exhibited excellent adhesion to metallic substrates. The addition of even small amounts of W provided greatly increased hardness compared with the plain Ni-P deposits. The wettability properties of the Ni-W-P deposits were found to be comparable to those of Ni-P and N-B-P deposits but inferior to those of Ni-B deposits. (C) Elsevier Science Inc., 1996
关键词:
nickel
