不锈钢电化学发黑新工艺

介绍了一种电解不合铬酸盐的不锈钢电化学发黑的新工艺，探讨了不锈钢进行电化学阴极的反应而发黑的机理及影响因素，该新工艺有五方面的特点。     

浅谈不锈钢电解发黑

不锈钢发黑工艺有多种多样,常见的是酸性化学法(碱性化学法因成膜太慢难以成批生产,很少被厂家采用)。而酸性化学法大致有二类,一类是“因科法”,在铬酐250g/L,硫酸490g/L的溶     

钢铁常温无硒发黑工艺的研究

针对传统的常温发黑工艺中所使用的亚硒酸或二氧化硒具有毒性大、价格昂贵的缺点,本文研究了一种常温无硒发黑工艺,探讨了发黑机理,研究了前处理、发黑液各成分及操作参数以及后处理对为黑膜质量的影响,提出了发黑液的维护措施,分析了常见发黑膜的缺陷并提出解决方法。结果表明：本发黑工艺具有无毒、高效、成本低、操作方便、黑膜耐磨、耐蚀性好等优点。     

304不锈钢敏化热处理对耐蚀性的影响

在８０℃的０．３５％ＮａＣｌ溶液中对不同敏化处理的３０４不锈钢的耐缝隙腐蚀及孔蚀等局部腐蚀性能进行了研究。同时，分析并比较了晶间腐蚀与耐蚀性能的相关性。     

304光亮不锈钢着色工艺研究

报道了在铬酸－硫酸着色液中加入适当的添加剂，对３０４光亮不锈钢进行了化学着色试验，测量了着色过程中的电位－时间曲线，确定了４种颜色的电位差值，还探讨了着色膜的硬化处理和封闭处理工艺。     

铝合金化学发黑工艺的研究

提出了铝合金化学发黑工艺,通过前处理、化学镀镍、电镀铜、再化学着黑色,可以获得高附着力、致密均匀的黑色氧化膜.筛选了最佳的工艺参数和工艺流程.该工艺简单,操作方便,具有推广和应用前景.     

链条链板零件常温发黑工艺及其应用

介绍了链条链板零件常温发黑工艺,论述了前处理、常温氧化发黑和后处理工艺的操作规范和控制要点。分析了发黑中常见缺陷产生的原因,提出了排除方法。应用实践表明,该常温发黑工艺具有节能、高效、操作方便、环境污染小和成本低廉的特点,各项性能满足客户要求。     

仿青古铜发黑工艺的改进

黄铜件及镀黄铜工件仿青古铜发黑工艺有两种:化学氧化发黑,电镀黑色镀层.     

化学镀镍-磷合金层发黑工艺的改进

0 前言 目前,化学镀镍-磷合金层的发黑工艺越来越受到重视,它不仅保持了化学镀镍-磷合金层的原有特点,而且还扩大了其应用范围,因此,被广泛用于太阳能集热器、光学仪器、计算机等行业.目前获得化学镀镍-磷合金发黑层的方法主要是将经过化学镀镍-磷的零件浸入含一定浓度的高锰酸钾或硝酸中,产生选择性腐蚀,从而获得黑色表面.     

钢铁发黑磷化工艺

为了获得装饰性、耐蚀性及外观符合要求的发黑磷化膜,采用开路电位-时间曲线、交流阻抗曲线、极化曲线、扫描电子显微镜、宏观描述等方法,对钢铁发黑磷化工艺中的温度、时间、游离酸度、总酸度、促进剂、配位剂、硫酸铜、钼酸钠、磷酸二氢锰等因素进行了研究。结果表明:在适宜的发黑磷化液配方和操作条件下,能够得到晶体数量多、晶体尺寸适中、缝隙小、平整致密、结合力和耐蚀性好的发黑磷化膜。发黑磷化液稳定,寿命长,沉渣少。     

一种实用的发黑工艺

详细介绍了一种实用的常温发黑工艺配方、各主要成分的作用和工艺参数的影响。阐述了该工艺的流程，溶液和发黑膜层的性能。     

DEIS assessment of AISI 304 stainless steel dissolution process in conditions of intergranular corrosion

Results presented in this paper are first that demonstrate instantaneous impedance changes versus reactivation potential detected by means of dynamic electrochemical impedance spectroscopy (DEIS) technique for AISI 304 stainless steel dissolution process proceeding during intergranular corrosion (IG) in 0.5 M SO₄²⁻ + 0.01 M KSCN solution of different pHs. Application of DEIS method made it possible to evaluate dynamic changes of the examined system's impedance in conditions of IG. As a result, controlling stage of the overall rate of AISI 304 SS dissolution process was determined. Moreover, the paper proposes an alternative way of assessment of AISI 304 SS dissolution rate during intergranular corrosion based on approximation to theory of iron dissolution in sulfuric acid medium. Simultaneously, on the basis of the DEIS measurements it was possible to obtain information about the degree of sensitization (DOS) of the examined material. Accordingly, performed researches revealed the advantage of the DEIS technique over the electrochemical potentiokinetic reactivation (EPR) tests when investigating intergranular corrosion process.     

Influence of impurities on stainless steels corrosion in wet process phosphoric acid

The corrosion behaviour of stainless steels in wet process phosphoric acid was studied by means of polarization curves and corrosion tests; in this context the influence of impurities that enhance the corrosivity of the acid, such as chlorides, fluorides and sulphates, was evaluated. Moreover the efficiency of some corrosion inhibitors, present as impurities in wet-process phosphoric acid, was evaluated by means of polarization curves and corrosion tests. Inhibitors of fluoride aggressiveness such as compounds of silicon, aluminum, magnesium were tested both separately and together. Trivalent iron as an oxidizing agent was also evaluated in order to minimize chloride-induced corrosion. Different grades of stainless steels such as AISI 316 L, Alloy 20, Alloy 28 and a duplex stainless steel 22Cr5Ni type, were taken into consideration.     

电解清除氧化皮的304不锈钢盘条耐蚀性的电化学评价

研究了电解清洗黑色和蓝黑色氧化皮304不锈钢盘条在盐酸和氯化钠介质中的耐蚀性能。动电位极化曲线方法测试了清洗后盘条的耐点蚀性能;恒电位充电曲线研究了不锈钢盘条的时间有效性。结果表明,电解清洗后不锈钢具有良好的耐蚀性。表面电子能谱测试表明清洗后不锈钢表面有显著的Mn元素富集,并探讨了Mn元素富集对耐蚀性的影响。     

酸性NaCl溶液中304控氮不锈钢腐蚀过程的声发射特征

采用声发射技术和电化学噪声技术研究了304控氮不锈钢C型环试样在0.5mol·L-1NaCl与1.5mol.L-1H2SO4的混合溶液中,恒载荷情况下的腐蚀过程。分析了腐蚀过程中所产生的声发射信号的振铃数随时间分布情况,以及不同阶段的声发射信号的频谱特征。同时对比分析了声发射检测结果与电化学噪声检测结果。结果表明,声发射检测技术对于304控氮不锈钢在酸性NaCl溶液中所产生的腐蚀声发射信号很敏感,在不同腐蚀阶段中,声发射信号特征差异明显,对于判断不同腐蚀阶段具有指导意义;声发射与电化学噪声测试结果基本一致,将声发射检测与电化学噪声检测结合使用,有助于使现场检测结果更加可靠。     

Corrosion of stainless steels covered by exopolymers

After a biologically induced corrosion in a 304 stainless steel tube electrochemical tests were carried out on the affected areas to characterise the nature of attack of the steel covered by the excreted exopolymers. Once the corrosive attack has been developed, the samples were removed from the solution, dried out for 1 month and re-immersed in the same well water which caused the attack. Polarization curves and impedance measurements made on non attacked welds, reference stainless steel and the metal covered by the exopolymer confirm that a reactivation of the corrosion process in previously damaged welded areas is produced. However, the corrosive attack has not been so severe than the initially produced by bacteria and after 28 days of immersion the progress of the attack is probably due to the previous activation of the steel surface rather than the microbiological activity.     

钢铁件常温快速发黑工艺及其维护

论述了常温发黑的基本原理,介绍了一种钢铁件常温快速发黑的工艺,其流程主要包括:化学除油,强腐蚀,再次化学除油,弱腐蚀,常温发黑及后处理.发黑液配方为:五水合硫酸铜20 g/L,硝酸钾3 g/L,亚硒酸20 g/L,六水合硝酸镍5g/L,85％磷酸5 mL/L,一水合柠檬酸12.5 g/L,二水合钼酸钠15 g/L,氯酸...     

AISI 304 L stainless steel decontamination by a corrosion process using cerium IV regenerated by ozone Part I: Study of the accelerated corrosion process

This paper describes the study of a new decontamination process of AISI 304L stainless steel from dismantled nuclear power plants. A very thin active contaminated surface layer was stripped from the underlying metal by corrosion in a solution of nitric acid with the addition of cerium nitrate. The Ce⁴⁺/Ce³⁺ concentration ratio was initially equal to unity and ozone/oxygen bubbles were used to regenerate Ce³⁺ ions into Ce⁴⁺ ions. The study was performed in a laboratory cell prior to preliminary optimization in a three-litre reactor. The objective was to obtain a corrosion rate of about 10 micrometers per day. This target was reached in 10^–2 mol l^–1 of cerium nitrate with bubbling of a 1.56 g h^–1 ozone flow in a 60 l h^–1 total gas flow. The corrosion rate depended essentially on the Ce⁴⁺ concentration. The stainless steel exhibited intergranular corrosion. The corrosion rate was monitored by measuring the solution oxidizing potential using a precious metal electrode.     

Passivity and passivity breakdown of 304 stainless steel in alkaline sodium sulphate solutions

The passivity and passivity breakdown of 304 stainless steel were investigated in 0.25 M Na₂SO₄solutions of pH 10. The effect of applied potential and the presence of Cl^– ions in the electrolyte were also studied. Different electrochemical methods such as open circuit potential measurements, polarization techniques and electrochemical impedance spectroscopy (EIS) were used. The results showed that the steel electrode passivates under open circuit conditions and also under potentiostatic control. The rate of passive film thickening under open circuit conditions follows a simple logarithmic law. Addition of Cl^– ion shifts the polarization curves in the active direction and above a critical chloride concentration, [Cl^– ] 0.15 M, pitting corrosion occurs and the pitting potential, E _pit, decreases linearly with the logarithm of [Cl^–]. The addition of sulphate ions to the chloride-containing solutions was found to inhibit the pitting process, and at [SO^2- ₄] 0.25 M, a complete immunity to pitting corrosion was recorded. The impedance measurements provided support for film thickening and film breakdown reactions. An equivalent circuit model which consists of a pure resistor, R , in series with a parallel combination of a pure resistor, R _p, and a constant phase element, Q, was proposed to describe the electrode/electrolyte interface. The passive film thickness was found to increase with applied potential up to a critical value of 0.3 V. At higher voltages, breakdown of the passive film occured.     

不锈钢槽体表面钝化工艺的优化

以50%(体积分数)的硝酸溶液对304和316化学镀镍用不锈钢槽体进行钝化处理,采用单因素试验和正交试验方法考察了钼酸铵及氧化钇的添加量、钝化时间和钝化温度对304和316不锈钢槽体表面钝化膜孔隙率的影响,确定了优化的钝化工艺条件如下:钼酸铵和氧化钇的添加量分别为硝酸质量的4.0%和0.4%,304和316不锈钢的钝化温度分别为40°C和35°C,钝化时间5 h。通过扫描电镜观察了钝化前后不锈钢的表面形貌,测定了钝化膜的组成。结果表明,钼酸铵和氧化钇的加入使钝化膜的孔隙率显著降低,提高了钝化膜的耐蚀性。优化工艺制备的钝化膜主要由Cr、Fe、Ni和Mo的氧化物组成,膜层平整致密。