Deformation-induced martensites in metastable austenite stainless steels affect their physical and chemical properties. Electrochemically induced annealing (EIA) is a recently discovered phenomenon. Although the reason why EIA treatment causes martensite to decrease or disappear is not clear, the effect of the martensite decrease or disappearance is supposed to be the same as that caused by heat-treatment annealing. The pitting resistance of the EIA-treated samples is compared with that of the untreated ones, through open-circuit potential, metallurgical microscope observation, and potentiodynamic scanning. The following results are obtained for the EIA-treated samples, after a 1.5-V anode charge in a 3.5 pct NaCl solution, as compared with the untreated samples: the deepest pit in the treated samples is far more shallow than the deepest pit in the untreated samples; there is far less pitting in the treated samples than in the untreated samples; and the largest pit in the treated samples is much smaller than the largest pit in the untreated samples. Initially, the open-circuit potential of the EIA-treated sample was 64 mV higher than that of the untreated one, but they reach close values after certain period of time. The pitting breakthrough potential, Eb, of the EIA-treated sample is about 0.2 V higher than that of the untreated one. Therefore, EIA is a method that has the potential to promote the pitting resistance of metastable austenite stainless steels.

亚稳奥氏体不锈钢冷变形后产生形变诱发马氏体,影响其物理和化学性能. 对打磨后的亚稳奥氏体不锈钢进行了阳极60s～280s + 阴极30s～280s ,9h电脉冲处理. 用X 射线衍射分析、显微硬度测量、自腐蚀电位测量和金相分析等方法分析处理前后的马氏体含量、表面硬度、耐腐蚀性. 结果表明处理后表面马氏体均减少. 随脉冲宽度的不同,电脉冲处理可以诱发电化学退火,也可以导致马氏体优先腐蚀. 当发生电化学诱导退火时,不锈钢不仅在马氏体减少后仍可以保持高硬度,而且在含Cl-介质中的耐蚀性也提高.

本文研究了SiCw/Al复合材料(碳化硅晶须增强铝复合材料) 的尺寸稳定性, 结果表明: 这种材料的微屈服强度、微蠕变抗力均明显高于其基体铝合金, 其热膨胀系数明显低于基体铝合金, 这种材料具有优异的尺稳定性。

纳米颗粒加入镀液可提高镀层的硬度,并可能影响镀层的耐蚀性能。用化学沉积法制备了纳米TiO2-Ni-P复合镀层。研究了pH值、温度对沉积速度的影响,及表面活性剂种类对镀层硬度的影响,并得出优化配方。镀态和不同温度热处理后的复合镀层的硬度都明显地高于Ni-P合金镀层。用化学法测得了镀层中的TiO2颗粒的含量为2.14%。镀层在400℃下热处理1h后,XRD分析发现镀层结构由非晶态转变为晶态,并出现了强化相Ni3P,其镀层硬度高达HV1100。在3.5%NaCl溶液中测定了合金镀层与纳米复合镀层的自腐蚀电位,发现二者的值相近,且都高于铁基体。

用电镀的方法制备出Ni-纳米TiO2复合电镀层,讨论了表面活性剂、阴极电流密度、搅拌速率等对复合镀层硬度的影响并分析了纳米TiO2的加入对复合镀层硬度、耐蚀性的影响情况。结果表明,与纯镍镀层相比,Ni-纳米TiO2复合电镀层的硬度可提高90～190 HV;添加阳离子表面活性剂分散纳米TiO2所得复合镀层硬度最高,说明阳离子表面活性剂有利于纳米TiO2-Ni复合电沉积。浸泡试验表明,在硝酸溶液中复合镀层的腐蚀速率高于纯镍镀层的腐蚀速率,但远低于未镀覆钢板的腐蚀速率;极化曲线表明,与纯镍镀层相比,复合镀层的自腐蚀电位没有显著提高。说明在复合镀层中添加纳米TiO2不能改善其耐蚀性。