Effect of Heat Treatment on Microstructure and Stress Rupture Properties of a Ni-Mo-Cr-Fe Base Corrosion-Resistant Superalloy

The influences of heat treatment and test condition on the microstructure and stress rupture properties of a Ni-Mo-Cr-Fe base corrosion-resistant superalloy have been investigated in this paper. Optical microscope and scanning electron microscope were employed for the microstructure observation, and X-ray diffraction, electron probe micro-analyzer, and transmission electron microscope were used for phase determination. It was found that the grain size increased and the volume fractions of initial M₆C carbides decreased along with the increase in solution treatment temperature. When tested at 650 °C/320 MPa, the stress rupture lives decreased with the increase in solution treatment temperature, but the stress rupture lives increased slightly at first and then decreased for the samples solution heat treated at 1220 °C when tested at 700 °C/240 MPa. The elongations showed the descendent trends under these two conditions. The stress rupture life and elongation for the aged samples all showed a noticeable improvement at 650 °C/320 MPa, but there was no noticeable improvement at 700 °C/240 MPa. The reasons can be attributed to the grain size, test conditions, and the initial and secondary carbides.     

Water-Lubricated Ni-Based Composite(Ni-Al_2O_3,Ni-SiC and Ni-ZrO_2)Thin Film Coatings for Industrial Applications

In this work,pure nickel and Ni-based nanocomposite coatings(N1-Al_2O_3,Ni-SiC and Ni-ZrO_2) were produced on steel substrate by using pulse electrodeposition technique.The industrial performance tests were conducted to evaluate the wear resistance,corrosion resistance,adhesion strength and wettability behaviour of newly developed coatings.Rolling contact ball-on-disc tribometer was used to assess anti-wear behaviour of these coatings under waterlubricated contacts.The results showed that the wear- and corrosion resistance properties of nickel alumina and Ni-SiC composite coatings significantly improved than that of pure Ni and Ni-ZrO_2 coatings.The adhesion and wettability results of Ni-Al_2O_3 composite showed better performance when compared to the rest of the coatings.The effects of incorporating nanoparticles on the surface microstructure,interface adhesion and distribution of the particles were also investigated.The coatings were characterized by using scanning electron microscopy,X-ray diffraction analysis and 3D white light interferometry.The wear failure behaviour of these coatings was further examined by post-test surface observation under optical microscope.     

Corrosion-resistant coating for cathode current collector and wet-seal area of molten carbonate fuel cells

High-temperature corrosion of metallic bipolar plates is a main problem to limit system reliability of molten carbonate fuel cells (MCFCs). In particular, cathode current collector (CCC) and wet-seal area in the bipolar plates suffer severe corrosion during MCFCs operation. Herein, we are trying to explore facile and cost-effective coating materials and methods to enhance corrosion resistance of CCC and wet-seal area of MCFCs. Cobalt (Co) layer was coated by using electrodeposition method for CCC, and aluminum (Al) layer was coated by using mechanical cladding method for wet-seal area. Co and Al layers were transformed into in-situ lithiated oxides, which are LiCoO₂ and LiAlO₂, by reacting with electrolytes without detachment. These in-situ formed oxides efficiently impede formation and growth of corrosion scales by preventing permeation of electrolytes. We believe that Co electrodeposition and Al cladding would be suitable and practical methods for making protective layers to enhance corrosion resistance of CCC and wet-seal area in the MCFCs bipolar plates.     

单组份聚氨酯防水防腐胶研制

用含羟基聚醚、聚酯与芳香族异氰酸酯反应制得性能全面的单组份聚氨酯粘接剂.其物理和化学性能和贮存稳定性与反应物、NCO/OH比、反应催化剂和工艺有关.结果表明该粘接剂在胺催化剂存在时由聚醚,羟值50—100、500—700;聚酯,羟值100—150、200—250;和芳香族异氰酸酯合成而得.它有优良的性能:抗张强度7.8MPa,延伸率:240%,耐磨性2.6mg/1000转.     

Diffusion welding of 12Cr18Ni10Ti steel to palladium alloy foil

The special features of the method of diffusion welding of corrosion-resisting steel with a palladium foil using an intermediate layer made of nickel are presented. The method can be used for producing full-strength and vacuum-tight welded joints.     

利用两种废物合成防腐防水涂料

长期处于有腐蚀介质（液体或气体）环境中的混凝土、水泥砂浆、砖石等建筑材料，会发生化学反应，导致强度降低、表层疏松、脱皮、结构损坏等。我们利用生活废物（一次性塑制餐盒）和工业废物（粉煤灰）研制出一种具有无机和有机双重优势的复合建筑涂料，可保护混凝土等建筑材料不受腐蚀。此种涂料耐酸、耐碱、耐高温（１００℃±）、耐低温（－３０℃±），能在干或湿基面上施工，室内外均适用     

常规液压钳钳牙咬痕对套管腐蚀破坏的研究

油井上广泛使用国产常规液压动力钳来快速上卸套管,在提高工作效率同时也降低了操作工人劳动强度,但也产生了套管外壁咬伤划伤的新问题。一旦在套管表面上留下明显咬伤造成套管表层的防腐层损伤,井下硫化氢等腐蚀性气体就会加速对套管腐蚀,减少套管使用寿命。     

Synthesis and characterization of corrosion-resistant and biocompatible Al2O3–TiB2 nanocomposite films on pure titanium

Alumina is widely used as a coating on a metal implant due to its favorable mechanical and biological properties. In this research, in order to improve mechanical and biological properties of alumina, a composition of nanoparticles of alumina (instead of microparticles) and titanium diboride micro powder is introduced. The atmospheric plasma spray (APS) technique was applied to deposit Al₂O₃–TiB₂ on the pure titanium substrate. The properties of Al₂O₃–TiB₂ nanocomposite coatings with various weight percent of TiB₂ (20, 30 and 40 wt%) were experimentally studied. The characteristics of nanocomposite films of TiB₂ (20, 30 and 40 wt%) were analyzed using Field Emission Scanning Electron Microscopy (FE-SEM), energy dispersive electron spectroscopy (EDX) and X-Ray Diffraction (XRD) tests. The XRD spectra exhibited that in addition to alumina and titanium diboride, the films contained titania. Thickness and morphology of the films were calculated from FE-SEM images and the thickness of the optimized coating (Al₂O₃-30 wt% TiB₂) was about 30–45 μm. Also, the roughness, corrosion resistance, hardness and cytotoxicity (MTT) tests were studied. The highest of hardness and roughness of the samples were obtained from Al₂O₃-30 wt% TiB₂. According to the obtained results from the polarization test, Al₂O₃-30 wt% TiB₂ coating had the highest corrosion resistance (222558.9962 Ω cm²). Therefore, the toxicity of Al₂O₃-30 wt% TiB₂ was investigated as the optimized coating and the results confirmed its non-toxicity and biocompatibility.     

多频管中电流法在长宁输气管线上的应用

简单分析目前埋地管道防腐层地面检测上常用的多频管中电流法，结合作者实际工作，介绍该技术在宁夏长宁天然气公司长宁输气管线防腐层检测评价中的应用。通过检测，共查出管道防腐层破损点137处，在对上述破损点进行开挖修补时，发现防腐层均存在不同程度老化及破损，证明该技术对于防腐层破损检测准确率达到100％，验证了多频管中电流法的准确性及科学性，同时，对使用中积累的经验进行总结，指出该技术在应用中尚存在一些局限性和不足之处。     

水性聚苯胺微乳液及其防腐涂料研究

利用改进的新型微乳液聚合法合成了聚苯胺水性微乳液,该微乳液不经破乳可直接应用于金属防腐涂料。将其与环氧树脂的共混乳液作为底漆、与环氧树脂面漆复合后,可制备出性能优良的水性金属防腐涂料。该复合涂层能将裸露钢板的平衡开路电位提高235mV左右,在自来水中至少可浸泡3个月不起泡、不生锈,是一种环境友好型绿色涂料。