浅谈环保型不锈钢表面处理

论述了低温或无铬环保型不锈钢表面抛光和着色工艺的现状、各种抛光和着色方法。通过列举一些有代表性的抛光和着色工艺配方,讨论了各工艺配方的特点,得出了综合性能较好的工艺配方。尤其对环保性能较佳的工艺方法作了讨论,提出了需要改进的方面。     

Modification of stainless steel surface hydrophobicity by silver nanoparticles: strategies to prevent bacterial adhesion in the food processing

The ability of silver nanoparticles to modify the thermodynamic characteristics of stainless steel surfaces in order to reduce the adhesion process and thereby inhibit biofilm formation was evaluated. We observed that silver nanoparticles were able to decrease the contact angle of stainless steel from 73.20° when conditioned with water to 12.10° making the surface more hydrophilic. Thus, the thermodynamics of adhesion for all the evaluated bacteria was more unfavorable when the stainless steel surfaces were conditioned with the nanoparticles. Regarding the bacteria, Staphylococcus aureus was the most hydrophilic (p?<?0.05) followed for Escherichia coli, Pseudomonas aeruginosa, and Listeria innocua. Thereby, the silver nanoparticles demonstrated efficiency in inhibiting theoretical adhesion by altering the surface hydrophobicity that can potentially hamper cellular adhesion and prevent biofilm formation.     

Characterization of zirconia modified porous stainless steel supports for Pd membranes

A thin well-bonded zirconia film was formed on a porous stainless steel support by a sol-gel dip-coating method followed by firing in hydrogen atmosphere. The zirconia layer has a cubic phase structure. The surface composition of the film was analyzed by X-ray photoelectron spectroscopy. A comparison between H₂-fired and air-fired samples indicated that the surface/interface composition of the sample fired in air was rich in Fe₂O₃, whereas that of the fired in H₂ contained more metastable cubic zirconia phase and spinel type iron chromate. Binding energy shifts of Zr and Fe in the mixed oxides, together with the presence of iron and chromium oxides suggests that interfacial reaction between the coating and the substrate occurred, which is favorable for a good adhesion of the layers. The average pore size of the support modified by multilayer zirconia coatings declined drastically from original 2 μm to the coated top-layer 0.4 μm. The ZrO₂ film showed a hydrogen selectivity of 2.7 for H₂/N₂, and a hydrogen flux of 1.159 × 10⁻³ mol/m².s at room temperature and with a pressure difference of 101 kPa across the film.     

不锈钢设备与部件的表面清理分析

不锈钢的表面清理关系到设备的质量、产品的纯度与耐蚀性能,因此有必要对不锈钢表面进行包括除油、酸洗、钝化、机械清理、电解抛光、精饰等处理。并对各种处理方法及清理后检测方法作了分析。     

Characterization of zirconia modified porous stainless steel supports for Pd membranes

A thin well-bonded zirconia film was formed on a porous stainless steel support by a sol-gel dip-coating method followed by firing in hydrogen atmosphere. The zirconia layer has a cubic phase structure. The surface composition of the film was analyzed by X-ray photoelectron spectroscopy. A comparison between H₂-fired and air-fired samples indicated that the surface/interface composition of the sample fired in air was rich in Fe₂O₃, whereas that of the fired in H₂ contained more metastable cubic zirconia phase and spinel type iron chromate. Binding energy shifts of Zr and Fe in the mixed oxides, together with the presence of iron and chromium oxides suggests that interfacial reaction between the coating and the substrate occurred, which is favorable for a good adhesion of the layers. The average pore size of the support modified by multilayer zirconia coatings declined drastically from original 2 μm to the coated top-layer 0.4 μm. The ZrO₂ film showed a hydrogen selectivity of 2.7 for H₂/N₂, and a hydrogen flux of 1.159 × 10^?3 mol/m².s at room temperature and with a pressure difference of 101 kPa across the film.     

Potentiostatic pickling: a new technique for improving stainless steel processing

The potentiostatic technique applied to the acid pickling of stainless steels gives remarkable advantages over the ordinary chemical treatment in terms of speed of scale removal and efficiency of restoration of the passivity properties of the pickled surface. Furthermore the potentiostatic control makes descaling and pickling of stainless steels feasible in sulphuric acid baths. Some aspects dealing with the economy of the process, such as weight losses and pickling solution life, have been considered.     

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。     

不锈钢管内表面镀铜

介绍了一种开采石油用不锈钢管内表面镀铜的工艺。给出了调整后的工艺流程。重点对不锈钢镀铜的内阳极及其选择作了介绍。内阳极有两种材质,分别为不溶性碳精棒和含磷铜棒。试验中用无磷纯铜代替了含磷铜棒作为酸性镀铜内阳极,并给出了阳极反应的特点与控制方法。批量生产实践证明,单个电流为20A左右,电镀时间20min时,产品质量满足要求。通过高压水冲刷检验,镀层与基体结合良好。     

压力容器用不锈钢的防腐处理技术

压力用不锈钢部件的腐蚀因素包括化学腐蚀、应力腐蚀以及电化学腐蚀。其中,电化学腐蚀是不锈钢腐蚀的主要因素。在分析不锈钢构件腐蚀机理的基础上,对于不锈钢部件的成分、力学性能以及焊接特性进行进一步的探讨。     

Preparation of polyurethane foam fine polishing wheel for stainless steel surface

Comparing with dry polishing, the wet-polishing of the stainless steel surface can significantly reduce dust, noise and other pollution, and improve the polished quality. Thus, it is important to develop new polishing tools. In this work, the effects of the foaming agent and diluents on the mechanical properties of the polyurethane foam (PUF) system were investigated, and then the effect of the filler of graphite on the structure and mechanical properties of PUF was studied. Furthermore, the PUF fine polishing wheel with aluminum oxide was prepared. Results show that the bi-component diluents combined cyclohexane and dimethylformamide significantly affects the porosity and hardness of the PUF matrix. The filler of graphite can decrease the mechanical properties of the polyurethane matrix and increase the porosity of PUF, consequently, improve the self-sharpening of the PUF polishing wheel. The PUF fine polishing wheel with aluminum oxide shows fine polishing performance.     

The prebond surface preparation of 301 stainless steel alloy

It was demonstrated that an acid etch increased the bond strength and environmental durability of 301 stainless steel bond joints. During the course of the acid etch, it was noted that a silicon rich smut was deposited on the adherend surface. Experimentation verified that a sodium dichromate/sulphuric acid solution removed the smut.It was noted that if the smut was not removed, the resulting bond joint was environmentally less stable than one which had been desmutted. Environmentally stable bond joints were obtained with an etch time of five minutes, acid concentration of twenty percent, and a temperature of 61°C, followed with a sodium dichromate/sulphuric acid desmut. From the etch data obtained, an empirical relationship relating weight loss to acid concentration, etch time, and temperature was established. SEM and Auger analysis characterized the surface characteristics of smutted and desmutted bonding surfaces.     

ZnO修饰的不锈钢网支撑体上ZIF-8膜的制备

ZIF-8因具有0.34 nm的孔道直径而被认为是最具应用前景的气体分离膜材料之一。不锈钢网（SSN）作为分离膜的支撑体具有价格低廉、易于裁剪、厚度薄等优点。采用水热法在SSN表面生长ZnO缓冲层,以ZnO修饰的SSN（ZnO/SSN）为支撑体制备ZIF-8膜。采用X射线衍射（XRD）和扫描电子显微镜（SEM）对合成的ZIF-8膜进行表征,并进行了气体渗透性能测试,结果表明,在ZnO颗粒修饰后的SSN支撑体上无需活化可制备出单一物相、无缺陷的ZIF-8膜;在室温（298 K）下,ZIF-8膜的H₂/CO₂、H₂/N₂、H₂/CH₄的理想分离系数分别为7.3、9.2、12.4;在150℃,ZIF-8膜的渗透性能稳定。     

磷酸在不锈钢表面处理中的应用

介绍了磷酸在不锈钢抛光、化学着色、蚀刻、电解除氧化皮、磷化、钝化及表面清洗中的应用。     

Controllable fabrication of superhydrophobic alloys surface on 304 stainless steel substrate for anti-icing performance

In this paper, 304 stainless steel-based ZnO (304SS-based ZnO) seed layer was prepared by using sol-gel method or electrochemical deposition. Superhydrophobic nano-ZnO (CSS–ZnO) surface were prepared on its surface by hydrothermal method. The results show that different structural morphologies of 304SS-based ZnO surface were prepared by varying different seed layer preparation methods. In the static icing test, compared with hydrophilic nano-ZnO (SS–ZnO) surface, hydrophobic nano-ZnO (QS-ZnO) surface and 304SS surface at −5 °C, −10 °C and −15 °C. The icing time of CSS-ZnO surface was prolonged by about 2.7 h at −5 °C, delayed by about 40 min at −10 °C and delayed by about 9 min at −15 °C. The CSS-ZnO surface is the most effective surface in static anti-icing. It is because that there has a residual air layer at the solid-liquid interface and the coating can still effectively retard ice formation in a partially wetted state. In the dynamic icing test, compared with QS-ZnO surface, SS-ZnO surface and 304SS surface at −16 °C, SS-ZnO surface and QS-ZnO surface have no anti-icing effect, and CSS-ZnO surface has a significant anti-icing effect. The mechanism for inhibiting condensation of water droplets by superhydrophobic surfaces was illustrated, which can be identified that the contact angle of the ice embryo will increase with the increase of the water contact angle. This work provides a practical application for promoting anti-icing ability of 304SS surfaces in industry.     

Mechanical and electrochemical behavior of nanocrystalline surface of 304 stainless steel

This paper reports our recent studies on nanocrystalline surface layer of 304 stainless steel (304SS) produced using a sandblasting and annealing process. The grain size of the sandblasted surface layer was less than 20 nm. Mechanical and electrochemical properties of the nanocrystalline surface and its passive film were investigated using nano/micro/-indentation, micro-scratch, scanning Kelvin probe (SKP), potentiodynamic scanning and electrochemical scratch techniques. It was demonstrated that the nanocrystalline surface was markedly superior to that of original 304SS with enhanced passive film. The polarization, electrochemical scratch and SKP measurements indicated that the nanocrystalline surface had higher resistance to corrosion, greater capability of repassivation and higher chemistry stability. All results demonstrated that the nanocrystallization surface did not only enhance the mechanical properties of the surface layer and its passive film, but also benefited the passivation capability of the steel with improved corrosion resistance.     

Elaboration of PIM feedstocks with 316L fine stainless steel powders for the processing of micro-components

The paper is concerned with the way to prepare feedstocks for powder injection moulding of fine stainless steel powders. The way to prepare adequate feedstocks is described, and injection moulding experiments are determined. The effects of powder volume loading, as well as mixing conditions are investigated and the results indicate that powder loading, injection moulding conditions and sintering kinetics largely influence the resulting shrinkage after sintering. Finally, the modelling and associated numerical simulations are used the help process design.     

采用ICP对304不锈钢表面黑色腐蚀物的分析

通过采用ICP对304不锈钢表面黑色腐蚀物的分析,发现黑色腐蚀物具有富Ni、贫Fe、Cr的特征,各金属的含量分别达到：Fe13．55％、Cr23．29％、Ni57．54％。分析了黑色腐蚀物在不同环境下的溶解性,并推测了对碱液质量的影响。     

换热表面Ni-W-P镀层抗垢特性

通过调整Ni-W-P化学镀镀液中钨酸钠浓度,获得了钨元素含量不同的三元Ni-W-P镀层。进一步的实验研究表明,随着三元Ni-W-P镀层中钨元素含量的增加,其热稳定性得到显著改善,同时,镀层晶粒转变的激活能值呈增大趋势。三元Ni-W-P镀层的抗垢性随着镀层中钨元素含量的增加而降低,而与镀层表面自由能以及表面粗糙度没有必然的联系。