阴极等离子体电解沉积Co、Cr金属涂层及Ni-Cr、Co-Cr合金涂层

采用阴极等离子体电解沉积的方法制备了Co、Cr金属涂层以及Ni-Cr、Co-Cr合金涂层,并研究了不同主盐浓度和酸浓度对涂层结构和形貌的影响。结果表明,在阴极等离子体电解沉积过程中,涂层形貌演变规律主要取决于沉积速率和等离子体电弧的作用。较低的主盐浓度和较高的酸含量可以降低沉积速率,在等离子体电弧的作用下,沉积物可以充分地快速熔融并凝固,形成均匀、致密的涂层;而在较高的主盐浓度和较低的酸含量下,由于沉积速率快,大量的沉积物无法完全被等离子体电弧熔融,所以易形成枝晶或者粉末。     

微波热处理制备硅化物涂层及其抗高温氧化性能

通过微波加热包埋渗法在高铌钛铝合金基体上制备了硅化物涂层,微波加热功率2.6 kW,埋渗时间2 h。利用扫描电镜、能谱分析和X射线衍射等手段研究了氧化前后涂层的表面形貌、截面形貌、涂层中元素分布和物相组成。结果表明：涂层外部主要物相为TiSi2和NbSi2,并有少量的Ti5Si3和Nb5Si3相,厚度约为15μm;内侧涂层有大约15μm的富铝层。1000℃下氧化100 h的氧化动力学测试结果表明：高铌钛铝合金渗硅后的抗高温氧化性能、抗剥落性能有了显著提高,其单位面积增重量和剥落量分别是0.5714 mg/cm2和0.7143 mg/cm2,仅为无涂层试样氧化增重量和剥落量的1/22倍和1/59倍。     

Controlling limiting length of tunnels on Al foil electroetched in HCl-H2SO4 solution

The limiting length of tunnels, llim, of Al foil electro-etched in HCl-H2SO4 solution and the corresponding anodic polarization curves in the same solution were measured. It is found that there is a dependence of llim on the potential difference, △φ, between the pitting potential, φpit, and the corrosion potential, φcorr, of Al foil, when the temperature and H2SO4 concentration of HCl-H2SO4 electrolyte are changed. The dynamic equation on the tunnel growing and the linear equation between llim and △φ were deduced by analyzing the relationship among the over-potential on Al foil surface, the transport over-potential in tunnel solution and the over-potential at tunnel tip during the electro-etching. The results show that the growing velocity of tunnels decreases with their extending in length and the changing trend of llim can be judged by measuring △φ, which supplies a convenient access to explore new kinds of etchants.     

复合料浆热压滤法制备空间网络复合涂层及其高温氧化行为

采用复合料浆热压滤法制备出厚度在数十微米到数百微米之间可控的YSZ/YSZ、Al2O3/YSZ、Al2O3/YSZ-Al2O3和Al2O3/Al2O3复合涂层。微观形貌显示复合涂层由具有空间网络结构的YSZ或Al2O3包覆颗粒状YSZ或/和Al2O3组成。高温氧化实验结果显示,含有适量YSZ颗粒的Al2O3/YSZ-Al2O3复合涂层具有优异的抗高温氧化性能。为通过氧元素在复合涂层中的扩散行为深入分析其抗高温氧化性能,本文还基于复合涂层的微观结构及高温氧化行为表现,建立与之相对应的简化模型。     

Flame Pyrolysis Spraying of Alumina-Yttria Ceramic Coating

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络合沉淀法制备球形秀明氧化铁黄颜料

以FeCl3和NaOH为反应试剂,NaF为络合剂,采用全新的络合沉淀方法,成功制备了球形的氧化铁黄颗粒,克服颜料色差大的缺点。     

烷基化换热器的腐蚀失效分析和防护措施

通过对烷基化车间换热器腐蚀形貌、特征、产物、腐蚀介质、积垢、材料以及换热器流体特性的研究和分析,认为烷基化换热器的腐蚀失效主要由空泡腐蚀和湍流腐蚀引起,并提出了4项防腐蚀措施.经现场应用证明:改变设计或安排辅助管可以有效地减缓冷却管与管板结合部位的严重腐蚀.     

Corrosion-erosion resistance of Zn-Al co-cementation coatings on carbon steels in aqueous media

A novel Zn-Al co-cementation coating was obtained by a pack cementation method,This coating possesses a two-layered structure,The outer layer is mainly composed of Fe2Al3 and FeAl intermetallics with a small amount of Zn,and the inner layer consists of Zn,Fe and a small amount of Al.The corrosion-erosion resistance of Zn-Al con-cementation coatings on carbon steel was studied by a rotary corrosion method in various NaCl and H2S containing solutions and relevant SiO2 containing media,The experimental results are compared with those of carbon steels and the sherardizing and aluminizing coating ,showing that the Zn-Al co-cementation coating have excellent corrosion-erosion resistance in various aqueous media.     

燃煤火电厂锅炉“四管”的高温腐蚀

燃煤火电厂锅炉的高温腐蚀主要发生在受热面的“四 管”,即水冷壁管、过热器管、再热器管和省煤器管.腐蚀的主要类型是硫腐蚀、氯腐蚀、 水蒸汽腐蚀和钒腐蚀.本文综述了燃煤火电厂锅炉存在的典型高温腐蚀现象和机理,并简要 的介绍了一般防腐蚀措施.     

Fe50Mo在硫蒸气中的高温硫化

应用TGA、XRD、SEM/WDS技术研究了Fe50Mo合金在1kPa,700～900℃的硫蒸气中的高温硫化行为.发现在700℃时硫化遵从抛物线规律,800和900℃时则变为线性规律.Fe50Mo的硫化速度常数比纯Fe的低3～4个数量级,比Fe20Mo和Fe40Mo的抗硫化性能有了显著提高.热处理对合金硫化行为无显著影响.最初只出现FeS单一硫化产物层,合金中发生μ相晶界处α-Fe相的选择硫化.长时间硫化后,FeS层下出现MoS2内层,其晶体片层垂直于样品表面,有助于扩散传质.但MoS2层致密、微观缺陷少