壳聚糖(CHT)吸附Cr(VI)的机理研究

动力学研究表明，ＣＨＴ能迅速和有效的从水溶液中吸附铬（ＶＩ），在初始铬（ＶＩ）浓度２０ｍｇ／Ｌ和ｐＨ３．２时，ＣＨＴ对铬（ＶＩ）的吸附１小时内可达９０％，按Ｌａｇｅｒｇｒｅｎ方程计算出一级速率常数为３．０５ｈ－１，吸附平衡的实验数据符合Ｌａｎｇｍｅｒｕｉｒ和Ｆｒｅｕｎｄｉｃｈ关系式，光谱研究表明，壳聚糖中—ＮＨ＋３与Ｃｒ２Ｏ２－７离子的相互作用主要是以氢键形式存在的静电引力。     

不锈钢母液的凝固点及流动性的实验研究

对不同含铬量的铁水凝固点和流动性进行了实验测定。结果表明，含铬铁水的凝固点和流动性与普通铁水完全不同，含铬铁水碳饱和时，铁水温度及含铬量是影响其凝固和流动性的主要因素，通过热力学分析解释了碳化物析出影响铁水流动性的原因。     

厚大型铸钢件防粘砂涂料的研制与应用

分析了厚大型铸钢件粘砂的机理，通过实验研究了可以替代铬铁矿砂的防渗透粘砂铸造涂料．实验表明，该涂料具有悬浮性高，刷感好，强度高的特点，不仅能起到防钢水渗透粘砂作用，提高铸件表面质量，而且由于取代了铬铁矿砂面砂工艺，简化了操作，降低了成本．     

利用EET理论预测Fe-C-Cr系高铬铸铁的淬硬性

为了揭示高铬铸铁组织的微观本质并利用其分析结果预测合金的淬硬性，利用余瑞璜的固体与分子经验电子理论(EET)和Fe-C-Cr三元系平衡相图对Fe-C-Cr三元系高铬铸铁合金奥氏体的价电子结构进行了分析。结果表明，在工业应用的成分范围内C-Cr键是合金奥氏体所有键中的最强键，形成C-Cr偏聚单元。wcr/wc≥6时，含C-Cr结构单元的权重会大大提高，促进了奥氏体的陈留，可以获得奥氏体基体组织。当wcr/wc=5．5-6．5时，Fe-C-Cr三元系高铬铸铁可获得最佳的淬硬性。     

TEM study on precipitation and transformation of secondary carbides in 16Cr–1Mo–1Cu white iron subjected to subcritical treatment

High chromium white irons solidify with a substantially austenitic matrix supersaturated with chromium and carbon. The subcritical heat treatment can destabilize the austenite by precipitating chromium-rich secondary carbides and other special carbides. In the as-cast condition the eutectic carbides are (Fe,Cr)₇C₃ and (Fe_4.3Cr_2.5Mo_0.1)C₃. The initial secondary carbide precipitated is (Fe,Cr)₂₃C₆ after heat-treating at 853 K for 10 h. There are MoC, Fe₂MoC and -carbide precipitating, and (Fe,Cr)₂₃C₆ transforms to M₃C after 16 h at 853 K. The -carbide and (Fe,Cr)₂₃C₆ accomplish transformation to M₃C and the matrix changes from martensitic to pearlitic after 22 h at 853 K. Thereby, in the subcritical heat treatment process, the initial secondary carbide precipitated is (Fe,Cr)₂₃C₆, followed by -carbide, MoC and Fe₂MoC. In addition, there are two in situ transformations from (Fe,Cr)₂₃C₆ and -carbide to M₃C carbides.     

The application of high resolution electron microscopy to the study of oxidation

High resolution electron microscopy has been used to examine both the similarities and differences in the growth morphologies of Fe₂O₃, Cr₂O₃ as formed on iron alloys, and MgO as formed by burning Mg in moist air. A general discussion is also given of the relative advantages and disadvantages of a variety of TEM techniques as applicable to the study of oxidation phenomena.     

间歇电沉积粒状铬镀层的过程及其性能

为改善镀铬板的可焊性,用间歇电沉积法在钢板表面获得了呈粒状分布的铬镀层.采用扫描电子显微镜、能谱仪和X射线衍射研究了电流中断时间对粒状铬形貌和结晶取向的影响;然后利用库伦电解法测量了镀层的铬含量;最后通过测量接触电阻和观察焊接面评价了其可焊性.实验结果表明:粒状铬镀层呈现为分散粒状铬均匀分布在连续层状铬上,随电流中断时间的延长,粒状铬密度逐渐增加,焊接电阻逐渐变小.相比于连续电沉积,间歇电沉积所得铬镀层出现了铬(211)晶面的择优取向.相同电荷量下,间歇电沉积所得铬镀层的镀铬量比连续电沉积的要高.电流中断时,生成不连续的氧化膜使得层状铬局部钝化,而活性点优先放电形成分散的粒状铬.同一压力下,间歇电沉积所得镀铬板的接触电阻远小于连续电沉积的;一定焊接电流下,前者可以焊接,而后者不能.电流中断期间,局部钝化的出现有助于粒状铬的生成,使得镀铬板的可焊性提高.     

Influence of chromium diffusion and different surface finishes on the oxidation behaviour of chromium steels

Abstract

The present contribution is focused on the systematic investigation of the effects of different surface finishes (ground, polished, electropolished) on the oxidation behaviour of chromium steels. The specimens were oxidized in a H2–2.5%H₂O atmosphere at 872 K for 1 h to 100 h. Depth profiles were recorded by secondary neutral mass spectrometry (SNMS) to determine the elemental composition of the oxide scale and the diffusion profiles below the scale. The surface finish was found to influence both the thickness of the oxide scale and the depletion of the selectively oxidized elements.     

从铬离子析出量的检测结果谈谈不锈钢食具的质量控制

对大量不锈钢食具及其原材料的铬离子析出量检测结果进行分析后,发现从原材料的选择到加工过程中力的变化、热处理和冷处理的工艺、表面粗糙度等均会影响不锈钢食具的铬离子析出量,本文提出在工艺上对奥氏体材料进行固溶、稳定化和去应力退火处理等以提高其耐腐蚀性能,在管理上加强对产品原材料、中间环节半成品及最终的成品进行严格的检测、记录、跟踪、监督,利用检测结果指导工艺改进,监督工艺成效,从而提高产品合格率,达到从产品源头开始控制产品质量的目的。     

生物除铬的机理研究

本论文主要是研究厌氧微生物作为生物絮凝剂吸附六价铬的吸附特性及机理。污泥中的微生物以杆菌为主。污泥吸附沉降性良好。污泥在吸附时间40 min内,不会解析,吸附效果最好。在污泥吸附能力达到饱和时,加入营养经过一段时间后,其吸附能力会部分恢复。