Preparation of a two-dimensional polymer film on passivated iron by modification of a carboxylate ion self-assembled monolayer with alkyltriethoxysilanes for preventing passive film breakdown

The effect of an ultrathin, regularly arranged polymer film on prevention of passive film breakdown on iron in the presence of chloride ion was investigated. The film of two-dimensional polymer was prepared by modification of a 16-hydroxyhexadecanoate ion self-assembled monolayer adsorbed on a passivated iron electrode with 1,2-bis(triethoxysilyl)ethane(C₂H₅O)₃Si(CH₂)₂Si(OC₂H₅)₃ and octyltriethoxysilane C₈H₁₇Si(OC₂H₅)₃. The pitting potentials of the passivated electrodes bare and covered with the polymer film were determined by anodic polarization measurements in a borate buffer solution containing 0.1 M of Cl⁻. The pitting potential of the coated electrode was higher than that of the uncoated one, indicating prevention of passive film breakdown. No breakdown was observed over the potential range in the passive and transpassive regions by covering the passive film with the well-arranged two-dimensional polymer film. The film was characterized by X-ray photoelectron and FTIR reflection spectroscopies and measurement of the contact angle with a drop of water.     

试验条件对钨铬铸渗层冲击磨损性能的影响

采用传统的铸渗工艺在铸钢件表面制备了钨铬复合层,采用MLD-10型动载磨料磨损试验机研究了试验条件对表面复合材料冲击磨损性能的影响.结果表明:随着冲击次数的增加,表面复合材料的磨损率逐渐增加,但在比较长的时间内,没有出现剧烈磨损和突然失效现象,显示出良好的耐磨性;随着冲击功的增加,复合材料的磨损率增加.     

Effect of Fe-Zn alloy layer on the corrosion resistance of galvanized steel in chloride containing environments

In this study, the effect of Fe-Zn alloy layer that is formed during galvanizing process on the corrosion behavior of galvanized steel has been investigated. The galvanostatic dissolution of galvanized steel was carried out in 0.5 M NaCl solution to obtain the Fe-Zn alloy layer on the base steel. The alloy layer was characterized to be composed of FeZn₁₃, FeZn₇ and Fe₃Zn₁₀ intermetallic phases, which constitute the zeta, delta1 and gamma layers of galvanized steel, respectively. It was observed that the alloy layer has similar cathodic polarization behavior but different anodic polarization behavior compared to galvanized steel. The anodic current plateau of alloy layer was up to 100 times lower than that of galvanized coating. Corrosion test performed in wet-dry cyclic condition has shown that the alloy layer has lower corrosion rate as compared to galvanized steel. From the results of corrosion test of alloy layer and base steel, it was concluded that Zn²⁺ has positive effect on the protectiveness of the zinc corrosion products. The measurement of surface potential over the alloy/steel galvanic couple has confirmed the galvanic ability of alloy layer to protect both the alloy layer itself and the base iron during initial stage of atmospheric corrosion.     

电渣溶炼浇铸法制备金属模具

本文简述了用电渣炼浇铸法制备金属模具的工艺原理和该方法的应用前景。     

模铸中碳钢偏析的改善

简要介绍和分析了宝钢集团五钢公司改善模铸中碳钢头部碳偏析程度的技术措施。     

The Inhibitive Effect of Traces of SO2 on the Oxidation of Iron

The oxidation of Fe was investigated at 500–700°C in the presence of O₂ with 0–1000 ppm SO₂. The exposures were carried out in a thermobalance and lasted for 24 h. The oxidized samples were investigated by grazing-angle XRD, SEM/EDX, GDOES and XPS. The rate of oxidation of pure iron is slowed down by traces of O₂ in O₂ below 600°C while SO₂ has no effect on oxidation rate at higher temperatures. Exposure to SO₂<600°C resulted in the formation of small amounts of sulfate at the gas/oxide interface. In addition, sulfur, probably sulfide, accumulated at the metal/oxide interface. The influence of SO₂ on oxidation rate is attributed to surface sulfate. The sulfur distribution in the scale is rationalized in terms of the thermodynamic stability of compounds in the Fe–O–S system. Exposure to SO₂ caused the formation of hematite whiskers.     

超低碳不锈钢铸件的生产

介绍了ZG00Cr24Ni20Mo2Cu3超低碳不锈钢锌件的生产过程。根据铸件工艺结构难点和严格的技术条件要求,合理制定了铸造工艺,正确地使用冷铁,成功地生产出合格铸件。     

低温铸钢Ni5.5的研究

设计1种新型无碳化物贝氏体Ni5．5铸钢。从成分设计、热处理工艺的选择、性能及低温冲击韧性等方面进行研究。结果表明，Ni5.5铸钢具有无碳化物贝氏体结构，贝氏体以巨型台阶方式形成，良好的机械性能和低温冲击韧性，适用低温至-80℃的工况环境中。     

铸造亚共晶铝硅合金绿色化规划探讨

根据绿色化思想，对铸造亚共晶铝硅合金进行了绿色化规划探讨。现有的铝硅合金牌号过多，以铸造亚共晶铝硅合金为例，中国至少有11种牌号，美国有14种，俄罗斯有16种，日本有11种。同时，这些合金的性能大多相互覆盖。这为材料选择，加工，管理和回收带来诸多不便。为了解决这些问题，规划出两种牌号，足以满足一般的要求，一种为低成本，中等性能合金（σb=150-200MPa,δ5＝1.0%-4.0%，如美国的356．0或中国的ZL101）；另一种为中等成本，中高性能合金（σ＝200－420MPa,δ5=2.0%-8.05,如我国新近开发的ZL120）。     

铸铁件电弧冷焊熔合区白口组织的控制

进行了冷焊条件下控制铸铁件焊补区白口组织的试验．结果表明，采用Ｓｉ－Ｃａ－Ａｌ－Ｂｉ系合金粉层对焊补熔合区进行集中强石墨化孕育处理及焊前在缺陷表面形成Ｎｉ基合金粉末喷涂层，均可消除熔合区白口