超声振动辅助加工表面微结构及其特性研究进展

针对超声振动复合加工方法种类繁多且表面微结构指征复杂等问题,阐述了表面微结构的内容和研究现状,论述了国内外超声切削、磨削、表面强化等方法的加工原理及超声振动加工表面微结构特性的试验研究方法,归纳了超声振动条件下表面粗糙度、表面微观形貌的建模方法及其特点,讨论了实验回归建模、数值解析建模和神经网络建模的研究进展,并预测了国内外超声振动表面加工的新技术领域和发展方向,对改善高性能难加工材料的表面微结构特性具有重要意义。     

提高材料摩擦学性能之稀土表面工程

表面改性过程中加入稀土元素对改善材料表面的摩擦学性能有显著的效果.稀土表面工程研究中可通过多种方法将稀土元素加入表面改性层,通常采用化学热处理、热喷涂和喷焊、激光表面处理等方法.本文综述了哈尔滨工业大学材料科学系的研究者们在该领域的研究情况,包括本文作者的研究和应用成果.     

激光表面改性技术及国内外发展现状

材料表面处理有很多种处理方法，应用激光对材料表面实施处理则是一门新技术，简述了激光表面改性的研究和发展现状，特别是激光表面淬火、激光熔凝，激光表面合金化合激光熔覆等四种技术，以各项技术的原理，特点和国内外研究现状分别加以描述，最后，还简述了激光冲击硬化和激光气相沉淀这两项技术，并且指出了激光表面改性技术存在总理2和发展前景。     

锆合金表面改性研究进展

综述了目前锆合金表面改性方面研究的进展状况。主要对表面预膜、离子注入和激光表面处理等3种方法进行总结。其中表面预膜主要简介了高压釜预膜、表面镀膜和阳极氧化等3种方法的研究现状：离子注入方面介绍了Y，La，Nb等离子注入对锆合金的改性效果及其原理；激光表面处理方面介绍了激光表面熔覆和激光表面合金化2种方法在锆合金表面改性方面的研究进展。     

粗糙纹理表面数字化模拟

粗糙表面的数字模拟是工件接触性能研究的前提与基础,而现有的粗糙表面模拟方法缺乏对表面纹理的考虑,为此提出了一种粗糙纹理表面数字化模拟方法.该方法通过数字化滤波模拟生成设定自相关函数的粗糙表面,同时模拟生成设定纹理参数的纹理表面,对粗糙表面和纹理表面进行归一化处理后,通过对纹理表面添加比例因子,将两表面进行合成处理,得到...     

涂层刀具微喷砂表面处理技术的进展

介绍了微喷砂表面处理技术进展及工作原理,分析了微喷砂处理对涂层刀具表面完整性、切削性能的影响。研究发现,微喷砂能够改善涂层刀具表面的粗糙度并提高涂层表面的残余压应力,进而提升刀具的切削性能并延长使用寿命。总结了微喷砂表面处理技术对涂层刀具表面的影响,并且对微喷砂表面处理技术进行了展望。研究结果为涂层刀具的表面处理和绿色智能制造提供了参考。     

电火花加工技术相关表面完整性的研究

表面完整性技术能有效地描述、鉴定和控制零件加工过程对零件加工表面层和工作性能的影响,在国外已成为制造技术的重要发展趋势之一。对于在加工中会产生变质层的电火花加工技术而言尤为重要,直接决定着电火花加工工艺和设备技术的应用效果及适用性。简要阐述了在民用和军用产品的关键件上开展表面完整性研究的途径和研究的重点及方法,基于此,提出了电火花加工表面完整性研究的思路和方案,为我国自行开展电火花加工的表面完整性研究提供参考。     

激光表面合金化FeCrNiSi合金层的耐蚀性

一、前言激光表面合金化是一种很有前途的表面改性技术,它通过改变金属表面的化学成份,从而改善其电化学行为。Si是改善孔蚀特性的有效合金组分,含Si4.45%wt的Cr18Ni8不锈钢的耐孔蚀性能大约比304不锈钢好20倍。采用激光表面合金化以形成FeCrNiSi表面合金在国内、外至今未见报导。本工作采用激光表面合金化技术对低合金钢进行Cr-Ni-Si表面合金化,研究激光处理工艺条件和合金成份对耐蚀性能的影响。     

塑性加工摩擦学研究的新方法——三维表面形貌分析

确定金属表面的粗糙度和结构是塑性加工摩擦学研究中的重要内容,但以往使用接触式粗糙度促进行测量的方法有很大局限性,目前国外已采用三维表面分析的方法进行测量和研究,本文介绍了三维表面分析原理、设备、主要特征参数、对表面的分析实例及其特点,使读者对这一新技术有一全面的了解。     

表面完整性研究现状及发展趋势

疲劳失效是金属结构失效的重要形式之一,提高零件疲劳性能可以有效增加结构使用寿命。对于低周和高周疲劳,绝大多数疲劳裂纹萌生于零件表面。因此,表面完整性对金属材料疲劳行为有重要影响。简述了表面完整性的内涵,指出表面完整性不仅包括如粗糙度、波纹度、表面裂纹等的表面形貌特征,也包含如加工之后零件表面的残余应力、塑性变形、组织形貌等物理化学变化特征。总结了表面完整性工艺的研究现状,说明机械铣削、电火花线切割、磨削、喷丸强化、光饰等加工工艺对表面完整性的影响。综述了表面完整性表征模型的建立,指出各表面完整性特征参数对表面完整性影响的比重。分析了国内表面完整性发展趋势,指出表面完整性工艺研究与表面完整性表征模型相互促进的作用,提出表面完整性工艺与表面完整性表征模型的交叉研究。最后,对提高表面完整性及建立影响表面完整性的参数模型提出了建议。     

Influence of drying temperature on the corrosion performance of chromate coatings on galvanized steel

The influence of drying temperature on the corrosion performance of chromate coatings on electro‐galvanized (EG) steel has been investigated using electrochemical impedance spectroscopy (EIS) and potentiodynamic measurements in 3.5% NaCl solutions. The chromate coatings were applied to the EG steel in a solution (pH 1.2) containing sodium dichromate and sulfuric acid at room temperature. The coatings were dried in an oven at three different temperatures: 60, 110 and 210°C. The surface of the chromate coatings was analyzed using atomic force microscopy (AFM) and scanning electron microscopy (SEM) combined with energy‐dispersive spectrometry (EDS). The results show that the drying temperature significantly affects the morphology of the chromate coatings and consequently affects their corrosion behavior. The chromate coatings dried at 110°C had few cracks and the lowest corrosion current. The chromate coatings dried at 60°C showed passivity. The EIS results show that the chromate coatings dried at 60°C has the largest impedance in a neutral 3.5% NaCl solution. Drying at higher temperature (210°C) degrades the chromate coatings by widening the cracks and reducing soluble Cr(VI) in the chromate layer. The favorable drying temperature for the chromate coatings on the EG steel is between 60 and 110°C.     

取代铬酸盐钝化处理工艺的动向

六价铬对人体、特别是对皮肤会造成伤害而成为环境问题,现在铬酸钝化膜,特别是镀锌层的铬酸盐钝化膜在欧洲已经受到限制。本文对铬酸盐钝化膜的性能以及所进行的以三价铬盐或无铬盐取代铬盐钝化的开发状况加以解说。     

Comparative Study of Factors Influencing the Action of Corrosion Inhmitors for Mild Steel in Neutral Solution: II. Potassium Chromate

Abstract

The action of potassium chromate as a corrosion inhibitor for mild steel in neutral aqueous solution has been studied in relation to the surface preparation of the steel, the presence of aggressive salts in the solution, and temperature.

Surface preparation of mild steel has little effect on the minimum concentration of chromate required for protection in distilled water. In solutions containing aggressive anions a linear relation exists between the logarithm of the chromate concentration and the logarithm of the maximum concentration of aggressive anion that will permit inhibition. In solutions of low chromate concentration, up to 10^?1M, the order of aggressiveness of anions is chloride > sulphate > nitrate; the order changes at chromate concentration above 10^?1M to chloride > nitrate > sulphate. Corrosion in non-inhibiting chromate/aggressive anion solutions is always of a localised nature but is usually stifled, thus not leading to ‘dangerous’ attack. A 5-fold increase in chromate requirement for inhibition of abraded mild steel in distilled water is found between 5° and 60°, with a further large, rather indeterminate, increase above 60°.     

A study of barrier film growth on aluminium in solutions of film-promoting and aggressive ions using secondary ion mass spectrometry

A Cameca Ion Analyser has been used to examine barrier-type anodic films grown on aluminium in neutral phosphate, chromate or phosphate/chromate solutions and in phosphate and chromate solutions containing relatively small amounts of chloride ion. Barrier layers grow at relatively high current efficiencies in phosphate solution, and are characterized by a rather wide phosphorus-containing layer adjacent to the oxide/solution interface. In chromate solutions, barrier layers grow at relatively low current efficiencies and contain little, if any, chromium resulting from the film growth process itself. Barrier layers grown in chromate-phosphate mixtures are generally typical of those grown in pure phosphate solutions, even at quite high chromate/phosphate concentration ratios. The presence of chloride ions in either phosphate or chromate solutions lowers the current efficiency of barrier film growth, and is associated with pitting of the aluminium substrate at the bases of flaws in the growing film, resulting in lateral undermining of the film. The results are explained in terms of a model for film development, involving growth partly by ionic migration and partly by a dissolution/precipitation process.     

环氧涂层中锌铬黄颜料对镁合金的防蚀机理

采用电化学阻抗、动电位极化、开路电位监测和X射线光电子能谱(XPS)等手段,研究了环氧涂层中锌铬黄颜料对镁合金的腐蚀防护作用,并分析了其防蚀机理。结果表明,锌铬黄防锈颜料均匀分散在涂层中,增强了涂层的屏蔽性能以及涂层与镁合金基体的结合力;在3%NaCl水溶液中,锌铬黄是一种阳极型缓蚀剂,它依靠铬酸根离子的阳极钝化作用形成钝化膜,阻滞了阳极腐蚀过程,造成涂层试样开路电位正移,使涂层试样的阳极极化增大。     

铝及铝合金表面铬酸盐转化膜的组成和结构研究——Ⅱ.红外光谱、X射线衍射、电子衍射和差热热重测试

本文报道了用红外光谱、X射线衍射、电子衍射和差热热重分析技术对铝及铝合金表面铬酸盐转化膜的组成和结构作进一步测定分析的结果。X射线衍射和电子衍射结果表明,转化膜为非晶态。转化膜主要组成为CrOOH·nH_2O,在较高温度下(～310℃),CrOOH将转化为Cr_2O_3。在用含有[Fe(CN)_6]~(3-)的铬酸处理液处理所得的转化膜中还含有少量的铁氰化物。     

局部硬质阳极氧化用铬酸阳极氧化膜层作保护层的工艺研究

针对目前铝合金零件局部硬质阳极氧化的工艺保护较为复杂,提出了一种容易操作的零件局部硬质阳极氧化的保护方法。试验表明,硬质阳极氧化后铬酸阳极化膜层的耐蚀性能良好。     

Electrochemical Behavior of 2205 Duplex Stainless Steel in NaCl Solution with Different Chromate Contents

The electrochemical behavior of 2205 duplex stainless steel in NaCl solution with different chromate contents were investigated by potentiodynamic polarization curves, electrochemical impedance spectroscopy (EIS), Mott-Schottky analysis, and scanning electron microscope (SEM). The effect of chromate on passivity and pitting behavior of stainless steel was also studied. The results showed that pitting susceptibility as well as semiconducting properties of passive film is heavily dependent on the chromate concentration. There exists a critical chromate value (about 0.03?M in 1?M NaCl solutions) below which the pitting corrosion on the stainless steel would be inhibited and above which it would be accelerated.     

Electrochemical investigations on the corrosion behaviour of galvanized reinforcing steels in concrete with chromate‐reduced cements

The reduction of the chromate contents in cements affects the electrochemical reactions of galvanized reinforcing steels in fresh concrete. By means of electrochemical measurements and bar pull‐out tests the effect of chromates on the formation of protective coatings at the zinc and the bond behaviour have been investigated using chromate‐containing and chromate‐reduced cements. The results have shown that the bond zone was affected as a result of chromate reduction for cement types CEM I and CEM II. The disturbance to the bond zone should be considered as long‐term in relation to the pore structure which is formed. The effects on the bond are largely compensated for as the concrete ages. The results of the related bond strength with displacement paths of 0.1 and 0.5 mm, respectively, are still within the range of expected figures for non‐galvanized reinforcing steel despite the structural disturbance. Under practical aspects it is not necessary that the existing structural disturbance with respect to bond strength is taken into consideration.     

钢材表面硅烷处理后的防蚀性能

采用硫酸铜点滴、线性极化、电化学阻抗等试验,对比研究了经硅烷偶联剂(SCA)和铬酸盐表面处理后的冷轧板的耐蚀性。结果表明经硅烷偶联剂表面处理后不但提高了基材的耐蚀性能,还提高了基材与涂层结合力,起到和铬酸盐钝化相同的防护效果。该方法有望取代造成环境污染的铬酸盐钝化工艺。