浅谈304奥氏体不锈钢离子渗氮

采用直流脉冲等离子体源对304不锈钢试样表面进行离子渗氮改性,通过XRD、SEM及显微硬度计对渗氮前后的不锈钢试样表面进行成分、形貌及硬度分析,应用电化学阻抗谱分析渗氮前后试样表面的耐蚀性能。结果表明:渗氮后,不锈钢试样表面形成了γ_N相改性层,γ_N相改性层的平均硬度值为HV_(0.1N)690.1 MPa,比渗氮前的硬度提高了5倍多。与渗氮前相比,渗氮后的容抗弧直径变大,中频区相位角平台显著变宽,说明氮离子注入层使电极反应速率变慢,腐蚀速度减小,耐蚀性增强。     

304奥氏体不锈钢低温盐浴氮化处理及其耐蚀性

采用低温(430°C)盐浴对304奥氏体不锈钢进行氮化处理,研究了氮化时间对渗氮层组织、显微硬度及耐蚀性的影响。分别用X射线衍射仪(XRD)、表面显微硬度计、光学显微镜分析了渗氮层的相组成、显微硬度、截面形貌和厚度。结果表明,304不锈钢表面的渗氮层厚度和显微硬度都随处理时间的延长而增大。氮化处理1h得到的渗氮层由单一的S相组成。经盐浴渗氮处理的304不锈钢,其耐Cl-点蚀性能得到改善,430°C下氮化4h得到的渗氮层耐蚀性能最好。     

304不锈钢低温盐浴氮化处理后的微观结构及耐冲刷腐蚀性

在430℃下对304奥氏体不锈钢进行低温盐浴氮化处理,并用X射线衍射(XRD)、光学显微镜(OM)、能谱(EDS)、扫描电镜(SEM)和显微硬度计研究了氮化时间对渗氮层厚度、组织结构、显微硬度和耐冲刷腐蚀性能的影响.结果表明,渗氮层厚度和表面显微硬度均随渗氮时间的延长而增加.氮化时间为1h时,氮化层仅为单一的S相;氮化16h时,氮化层由CrN和S两相混合.氮化层中的CrN随渗氮时间延长而增多,氮化40 h时氮化层析出大量CrN.盐浴渗氮处理后,304不锈钢的耐冲刷腐蚀性能得到了一定的改善.在430℃氮化16h,其耐蚀性能最好.随着渗氮时间的继续增加,304不锈钢的耐冲刷腐蚀性能降低.     

镁合金微弧阳极氧化-电泳涂装的研究

将镁合金表面微弧阳极氧化预处理后,再经过纳米改性电泳涂装得到了复合涂层,并对复合涤层的耐蚀性能进行了评价.金相显微观测表明,纳米改性电泳漆膜表面有较均匀的小突起,而未改性复合膜层表面比较光滑.常规性能测试表明,与未改性复合漆膜相比,经改性后的复合涂层漆膜附着力、硬度及抗冲击性能都有所提高.盐雾试验和电化学阻抗曲线表明:...     

Ti75钛合金微弧氧化膜的制备及性能

在含硅酸钠10g/L、六偏磷酸钠2g/L、柠檬酸钠2g/L和添加剂4g/L的电解液中,以微弧氧化技术在Ti75钛合金的表面成功制备了微弧氧化膜。采用涡流测厚仪、扫描电镜、X射线衍射仪、显微硬度计等手段研究了微弧氧化电压和时间对钛合金微弧氧化膜厚度的影响,分析了氧化膜层的表面形貌、组成、硬度、耐蚀性能及高温性能。结果表明,微弧氧化膜层主要由金红石型和锐钛矿型二氧化钛组成。氧化电压升高,膜层厚度增加;氧化时间延长,初期膜层厚度增加明显,20min后膜厚增加减缓。经微弧氧化处理后,钛合金的硬度、耐蚀性能和高温抗氧化性能均得到了明显改善。     

铝-锂合金阳极氧化及膜层性能的研究

采用恒电压直流方法,在硫酸溶液中铝一锂合金表面能形成阳极氧化膜.用扫描电子显微镜和腐蚀电化学方法研究了添加剂对氧化膜层表面形貌和膜层硬度及耐蚀性能的影响.结果表明:氧化液中加入草酸,氧化膜硬度显著提高;加入草酸和硫酸镍,铝-锂合金阳极化膜层在质量分数为3.5%的NaCl溶液中耐蚀性能最优.     

17-4PH不锈钢热浸镀铝及其高温耐氧化性能

在17-4PH不锈钢上热浸镀铝,然后进行扩散退火处理.研究了热浸镀铝层的显微组织和显微硬度的变化,并考察了其高温耐氧化性能.结果表明:17-4PH不锈钢热浸镀铝后表面分为富铝层、合金层、基体层等3层,合金层主要相为Fe2Al5.经950℃.1 h的扩散处理后,富铝层全部转变为合金层,厚度约为100 μM,且分为内扩散层...     

不锈钢化学法厚膜处理工艺

不锈钢钝化，一般是在30％的硝酸溶液中浸渍处理的，这种钝化膜很薄，况且延长处理时间并不能使其膜层厚度增加，因而耐蚀性极其有限。特别对马氏体不锈钢来说，用硝酸法处理，难以获得理想的耐蚀性能。故国内外电镀界人士，为研制不锈钢厚膜工艺进行着不懈的努力。不锈钢在酸性溶液里阳极电解是能获得比硝酸法所能得到的要厚得多的钝化膜。严格地说，这应当叫作“不锈钢氧化膜”。该法的缺点是，电流的“尖端效应”造成零部件各处的膜层厚度不均匀；前处理要求苛刻，因为零部件表面倘有“油”，就会在电解过程中国电位差的存在而产生电化学…     

热浸镀锌层表面钛盐转化膜研究

利用钛盐成膜工艺在热镀锌层表面获得了色泽光亮、耐蚀性能优良的银白色转化膜层。采用扫描电镜、能谱仪、电化学极化和盐水浸泡方法研究了钛盐转化膜层的表面形貌、元素组成和耐蚀性能。分析了钛盐溶液成分及工艺参数对热镀锌层表面转化膜的耐蚀性能影响。确定的最佳工艺条件为:Ti(SO4)21g/L,H2O260mL/L,pH0.5～1.0,处理温度25～30°C,处理时间10min。热镀锌层经此工艺处理后,耐蚀性能明显提高。     

不锈钢化学抛光工艺的研究

0 前言 不锈钢具有优良的耐蚀性、耐磨性、可塑性,因此,不锈钢制品被广泛应用于化工、纺织、食品机械、仪器仪表、厨房炊具、医疗器械等[1].由于不锈钢制品在机械加工时往往会形成一层灰黑色的氧化皮,不仅影响其表面质量,更严重影响其耐蚀性能.因此,不锈钢制品的表面处理就显得尤为重要,对其表面进行化学抛光可大大提高其耐蚀性能和装饰效果.     

不锈钢电解着色工艺及电化学性能

对１Ｃｒ１７铁素体不锈钢电解着黑色工艺和膜层的电化学性能进行探讨。本工艺具有发黑速度快,色泽均匀,较好的抗蚀性能。电解着色不锈钢表面形成铬的复合氧化膜,增强了钝性,使得自然电位和阳极极化电位正移,提高了膜层的电化学稳定性能。     

不锈钢环保抛光和着色工艺开发现状

概括了国内外环保型不锈钢抛光和表面着色工艺技术的现状和发展动态。介绍了一些典型的无铬环保型不锈钢表面化学和电化学抛光以及含铬低温和无铬型着色工艺配方。指出激光表面处理与传统工艺相结合的无铬环保型不锈钢表面处理技术具有广阔的发展前景。     

不锈钢表面涂覆TiO2薄膜的耐蚀性研究

以钛酸丁酯为原料,采用溶胶-凝胶技术,在不添加其他溶剂的情况下在201型不锈钢基体上制备了TiO2薄膜,采用金相显微镜观察薄膜表面形貌,利用X-射线衍射仪对其晶型进行了表征,同时测量了薄膜试样的极化曲线,实验结果表明:在不锈钢表面涂覆TiO2薄膜能够增强不锈钢基体的耐蚀性。     

316L不锈钢在硫酸盐还原菌与铁氧化菌溶液中的腐蚀及电化学行为

1 INTRODUCTION Type 316L stainless steel has good corrosion re- sistance and has been used increasingly for cooling water service in the chemical, petrochemical and power utility industries. However stainless steel is susceptible to localized corrosion by chloride ions and reduced sulfur compounds[1]. The presence of micro- organisms on a metal surface often leads to highly localized damages in the concentration of the electro- lyte constituents, pH and oxygen levels[2]. These mi- croorg…     

不锈钢电化学抛光技术研究

研究了不锈钢电化学抛光液中各成分的作用及操作条件对抛光质量的影响。本工艺在中温、小电流密度下能很快获得光亮、平整的抛光面。     

不锈钢表面抛光技术的研究进展

介绍了化学抛光、电化学抛光及复合抛光的特性、优缺点以及如何应用这些工艺技术对不锈钢进行着色前处理,指出了不锈钢表面抛光技术的发展方向。     

Stainless steel electrode characterizations by electrochemical impedance spectroscopy for dye-sensitized solar cells

Electrochemical impedance spectroscopy (EIS) was used to understand the electrochemical mechanisms which appear in dye-sensitized solar cells (DSSCs). This qualitative and quantitative technique permits identification of the phenomena proceeding within the different elements composing the cell and at their interfaces.In this study, the classical conducting glass substrate was replaced by a protected stainless steel (304 type) substrate as the counter-electrode (cathode) in dye-sensitized solar cells. Platinum was deposited at the substrate surface to optimize the charge transfer resistance of the electrode.After a few days of immersion in the electrolytic solution, stainless steel substrates coated with low thickness of Pt show pitting corrosion due to iodine. Defects in the Pt layer such as discontinuity of the film and micro-cracks may explain the corrosion of the stainless steel substrate. However the Pt layer degradation is retarded for thicker films. On the other hand, polished substrates show a better behaviour probably due to the elimination of the defects on the stainless steel surface.Electrolytic solution was optimized. For this, components such as 1-butyl-3-methylimidazolium iodide (BMII), guanidine thiocyanate (GT) and 4-tert-butylpyridine (TBP) were added. No corrosion phenomena on stainless steel 304 appeared within 3 days when TBP was added. This means that TBP acts as a corrosion inhibitor.A schematic equivalent circuit is also proposed.     

Electrochemical corrosion characteristics of type 316 stainless steel in simulated anode environment for PEMFC

The corrosion behavior of type 316 stainless steel in simulated anode environment for proton exchange membrane fuel cell (PEMFC), i.e., dilute hydrochloric acid solutions bubbled with pure hydrogen gas at 80 °C, was investigated by using electrochemical measurement techniques. The main purpose is to offer some fundamental information for the use of stainless steels as bipolar plate material for PEMFC. Both polarization curve and electrochemical impedance spectroscopy (EIS) measurements illustrate that 316 stainless steel cannot passivate spontaneously in the simulated environments. The absorbed (and/or adsorbed) hydrogen atoms from cathodic corrosion reactions on the steel surface may deteriorate the passivity and corrosion resistance. The oxidation of these hydrogen atoms gives rise to a second current peak in the anodic polarization curve, and the current increases with immersion time. EIS spectra also reveal that a porous corrosion product layer formed on the steel surface during the active dissolution in the test solutions. 316 stainless steel exhibits the similar corrosion behavior in sulfate ions containing dilute hydrochloric acid solution.     

The tribocorrosion behaviour of YSZ coating deposited on stainless steel substrate in 3.5 wt% NaCl solution

The YSZ coating was applied to 304 stainless steel substrate by atmospheric plasma spraying technology, and its electrochemical and tribological properties in 3.5 wt% NaCl solution were studied. In electrochemistry, under the action of cathode and anode potential, observe the changes of corrosion current density and EIS before and after wear. The results show that the YSZ coating has a very low corrosion current density during wear and corrosion compared to 304 stainless steel, and after the condition of the anode potential is applied, the effect of friction on the electrochemical impedance of the YSZ coating is very low, while the 304 stainless steel Impedance performance decreases; In terms of tribology, the friction coefficient of 304 stainless steel in 3.5 wt% NaCl solution is easily affected by potential, and the friction coefficient of YSZ coating relative to 304 stainless steel only changes under high potential. As the potential increases, the material volume loss of 304 stainless steel and YSZ coating increases linearly. From the data, the volume loss caused by the corrosion and wear of 304 stainless steel is much higher than that of YSZ coating.     

New sol–gel formulations to increase the barrier effect of a protective coating against the corrosion of steels

Films were deposited onto AISI 430 stainless steel substrates by dip–coating technique. The aim is to reach the AISI 304L stainless steel anti-corrosion properties by a coated AISI 430 stainless steel system. Sol formulation is done from the starting precursors tetraethylorthosilicate (TEOS) and 3(trimethoxysilyl)propyl methacrylate (MAP). After the hydrolysis of these precursors, sol–gel reactions occur before the addition (or not) of a controlled quantity of cerium nitrate. The addition of the PEG (polyethylene glycol), used as plasticizer has been studied in this paper and both physical and chemical properties of the synthesized hybrid films were studied by varying PEG ratios. Based on SEM observations and mass gain measurements, the thickness of the films has been adjustable. Another parameter plays a key role: the drying step of the whole system. It has been investigated and optimized in this paper to lead to coatings with a high barrier effect. The efficiency of the anti-corrosion protection of hybrid-coated stainless steel was investigated by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS) after immersion of the material in a 3.5% NaCl solution.