分光光度法连续测定镀铬液中Cr(Ⅲ)和Cr(Ⅵ)

研究了一种应用分光光度法对镀铬液中Cr(Ⅲ) 和Cr(Ⅵ)含量进行连续测定的化验方法.用Cr(Ⅵ)与DPCI的络合显色反应,在不同波长下对 Cr(Ⅲ)和Cr(Ⅵ)含量进行连续测定.确定了测定体系的各个参数,研究获得了一种不必将Cr (Ⅲ)和Cr(Ⅵ)分离即可对二者进行连续分光光度测定的快速分析方法,测定结果准确、操作简单.     

用透射和扫描电镜观察Ni—Cr—Al合金γ‘和Cr（α）析出相

Ｎｉ－Ｃｒ－３％Ａｌ－０．２％Ｃｅ合金０．３ｍｍ细丝经５００－６００℃时效处理，用透射和扫描电镜观察组织形貌，用化学定量提取法和测定微区成分的方法确定相Ｎｉ、Ｃｒ、Ａｌ的含量，用程控图像仪测定富Ｃｒ（α）相析出颗粒大小和分布，查明了γ相沿基体９１００）面共格析出并细小颗粒状，在γ相周围析出的过饱和富Ｃｒ（α）相弥散分布在合金基体中，据此认为该合金是由γ相和富Ｃｒ（α）相复合析出强化合金基体的。     

壳聚糖（CHT）吸附溶液中微量铬（Ⅵ）的研究

本文对壳聚糖ＣＨＴ吸附Ｃｒ（Ⅵ）的条件，吸附选择性进行了研究，研究结果表明，ＣＨＴ质子化后吸附的最佳条件是Ｃｒ（Ⅵ）溶液ｐＨ３￣４；吸附平衡时间１０￣１２小时，Ｃｒ（Ⅵ）浓度不大于６０ｍｇ·Ｌ＾－１。     

磺化褐煤对废水中Cr（Ⅵ）离子的吸附原与还原

在静态条件下，进行了以磺化褐煤作吸附剂、还原剂净化含铬铬废水的实验。研究了含铬废水的ＰＨ值、浓度和接触时间等因素对ＳＢＣ吸附、还原Ｃｒ（Ⅵ）的影响，确定了ＳＢＣ将化含铬废水的最佳条件。结合对实际含Ｃｒ（Ⅵ）废水的吸附、还原净化处理，讨论了ＳＢＣ对电镀废水处理的可行性。     

风化煤对废水中Cr(Ⅵ,Ⅲ)的吸附与解吸

研究了Ｃｒ（Ⅵ）和Ｃｒ（Ⅲ）被风化煤的吸附与解吸。在２０℃,滤速为４ｍｌ／ｍｉｎ,ｐＨ＝２、浓度为２０ｍｇ／Ｌ的Ｃｒ（Ⅵ）溶液,Ｃｒ（Ⅵ）的去除率达９９％以上,ｐＨ＝５、浓度为２０ｍｇ／Ｌ的Ｃｒ（Ⅲ）溶液,Ｃｒ（Ⅲ）的去除率达９８％以上。镀铬废水经二级吸附后,铬的总浓度为０．０８ｍｇ／Ｌ,低于国家排放标准。     

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Ｌａｇｅｒｇｒｅｎ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－ＮＨ３＾＋与Ｃｒ２Ｏ７＾２－离子的相互作用主要是以氢键形式存在的静电引力。     

添加剂对非晶态Cr电沉积的影响

用Ｘ－射线衍射法（ＸＲＤ）研究了添加剂含量对镀层形成非晶态的影响。测定了非晶态Ｃｒ电沉积的阴极电流效率高达３８％，高于传统镀Ｃｒ溶液。用线性电位扫描研究了非晶态Ｃｒ电沉积的电极过程，并且根据Ａｒｒｈｅｎｉｕｓ公式计算于非晶态Ｃｒ电沉积的表观活化能，研究结果表明，添加剂不仅促使镀层形成非晶态，而且可催化Ｃｒ的电沉积过程。     

纳米晶Sr-Cr水合石榴石的水热合成与磁性研究

在相对温和的水热体系旦合成出纳米晶Ｓｒ－Ｃｒ水合石榴石，采用ＸＲＤ、ＩＲ和ＸＰＳ光谱图对产物进行了表征。结果表明，高溶解性的初始物和高浓度的矿化剂大大降低其晶化温度，并提高其结晶度。随温度升高，出现Ｓｒ十二面体最近邻的ＯＨ＾－断裂与分解过程。在空气或氧气中，不出现了Ｃｒ（Ⅲ）到Ｃｒ（Ⅳ）氧化过程。骨架离子Ｃｒ（Ⅲ）的价态变化直接决定着水合石榴石的分解过程及其产物的结构类型。低温磁化率测量表明Ｓｒ３     

表面扩渗稀土（La,Ce）对1Cr18Ni9钢晶间腐蚀性能的影响

采用硝酸－硫酸铁腐蚀试验，扫描电镜（ＳＥＭ），电子探针（ＥＰＭ）等方法研究了气相扩渗稀土（Ｌａ，Ｃｅ）对１Ｃｒ１８Ｎｉ９钢晶间腐蚀性能的影响，结果表明，扩渗后钢表面几乎不存在贫Ｃｒ区，耐晶间腐蚀性能明显改善，超吉经稳定化处理的１Ｃｒ１８Ｎｉ９Ｔｉ钢水平。     

离子交换纤维对水中Cr（Ⅵ）的吸附与解吸

研究了水中Ｃｒ（Ⅵ）被ＰＳ离子交换纤维的吸附与解吸，在温度１５－３０℃滤速为６ｍｌ／ｍｉｎ时，浓度为１０ｍｇ／Ｌ的Ｃｒ（Ⅵ）溶液的除经在９８％以上。使用５％ａＯＨ溶液呆使该离子交换纤维再生，当流束上于０．４ｍｏｌ／ｍｉｎ时，洗脱率达到９５％，并具有较好的选择性和较长的使用寿命。     

Spectroscopic Properties of Bi12SiO20and Bi12TiO20Crystals Doped with Mn, Mn + P, Cr + P, Cr + Ga, and Cr + Cu

The absorption and circular dichroism spectra of Bi₁₂SiO₂₀and Bi₁₂TiO₂₀crystals codoped with Mn or Cr and a penta- (P⁵⁺), tri- (Ga³⁺), or divalent (Cu²⁺) element were studied. The results demonstrate that the sillenite crystals contain Mn and Cr in two oxidation states, 5+ and 4+. The introduction of P⁵⁺increases the fractions of Mn⁴⁺and Cr⁴⁺, while Ga³⁺and Cu²⁺have the opposite effect. The bands observed in the spectra are assigned to electronic transitions of [MnO₄]^4–and [MnO₄]^3–.     

Thermodynamics of Cr3+-Cr6+ equilibrium in borate melts

The Cr³⁺-Cr⁶⁺ equilibrium was studied in lithium and sodium aluminoborate melts in an air atmosphere at different temperatures. A mechanism of the Cr³⁺-Cr⁶⁺ redox reaction in glass melts has been suggested. Enthalpy and entropy of the reaction in molten borates were calculated and the results thus obtained have been discussed thermodynamically.     

三价铬天蓝色钝化工艺及其应用

介绍了锌镀层的ＳＷ三价铬天蓝色钝化工艺的特点及其推广应用。将三价铬钝化工艺与稀铬酸热封闭相结合可以得到外观和耐蚀性俱佳的天蓝色钝化膜。     

Cr~(3+)、Pb~(2+)在不同水泥水化体系中的固化

研究了重金属离子Cr~(3+)和Pb~(2+)对硅酸盐水泥、硫铝酸盐水泥及混掺水泥(普通硅酸盐水泥与硫铝酸盐水泥进行混掺)三种水泥的浆体凝结时间和力学性能的影响,并借助X射线衍射技术(XRD)和电感耦合等离子体发射光谱(ICP)等研究了水泥水化产物特征、重金属元素在水泥浆体中的固化方式与溶出特性。结果表明:Cr~(3+)对三种水泥均产生促凝作用,而Pb~(2+)对普通硅酸盐水泥和混掺水泥产生缓凝作用,对硫铝酸盐水泥产生促凝作用。Cr~(3+)和Pb~(2+)的掺加引起AFt和Ca(OH)_2形成量的变化,影响程度与水泥品种有关,掺加Cr~(3+)的28d浆体中有新相Ca_2Cr(OH)_7·3H_2O生成。所研究的三种水泥中,硅酸盐水泥对Cr~(3+)的固化效果最好,当Cr~(3+)掺量为1%时,其Cr~(3+)浸出浓度仅为0.177mg/L;而硫铝酸盐水泥对Pb~(2+)的固化效果最好,当Pb~(2+)掺量为1%时,其Pb~(2+)浸出浓度仅为0.0064mg/L。     

Fabrication of nanocomposites of alginate/pectin crosslinked with Ca2+ and its applications for the reduction of Cr6+ to Cr3+and sensor activities

Journal of Materials Science: Materials in Electronics - Composite gels of Alginate/Pectin/Dextran (Alg/Pec/Dex/Ca2+) with and without Au, or TiO2, or SiO2 NPs and then crosslinked with Ca2+ were...     

Passively Q-switched ceramic Nd3+:YAG/Cr4+:YAG lasers

Passively Q-switched ceramic Nd3+:YAG lasers with ceramic Cr4+:YAG saturable absorbers are demonstrated. When the lasers are pumped by a 1-W cw laser diode, optical-optical efficiency as great as 22% is obtained with Cr4+:YAG of initial transmission ranging from 94% to 79%. The results are similar to those in their crystalline counterparts. The operation of Brewster's angle and the polarization state of the laser output are also investigated.     

CsCdF3:Cr3+晶格畸变及其Cd2+-空位研究

按照零场分裂（ＺＦＳ）的三阶微扰理论和叠加晶场模型,建立了ＺＦＳ参量Ｄ与ＣｓＣｄＦ_３：Ｃｒ^３＋晶格结构之间的定量关系;同时考虑了晶格畸变和Ｃｄ^２＋空位对零场分裂参量Ｄ的贡献,计算了ＣｓＣｄＦ_３：Ｃｒ^３＋晶体的零场分裂参量Ｄ,计算结果与实验符合甚好．证明了晶格畸变和Ｃｄ^２＋空位的存在;同时得到包围 Ｃｒ^３＋离子的 Ｆ^－离子向中心 Ｃｒ^３＋离子分别移动Ｘ_１＝０．００２９１ｎｍ,Ｘ_２＝０．００１ｎｍ,Ｘ_３＝０．００２６ｎｍ．ＣｓＣｄＦ_３：Ｃｒ^３＋晶体基态的ＺＦＳ主要来自Ｃｄ^２＋空位,但晶格畸变的贡献是不能忽略的．     

A re-examination of the Kraft and Flinn diffraction data for Cr2B, (Cr,Fe)2B, and the boride phase in Fe + 18.5 wt % Ni + 20 wt % Cr + B alloys

Kraft and Flinn's [2] powder X-ray diffraction data obtained from excess-phase particles in Fe + 18.5 wt% Ni + 20 wt% Cr + B alloys have been analyzed. The major boride phase was determined to be (Cr,Fe)2B (orthorhombic, Fddd, isomorphous with Cr2B). Its lattice parameters, a = 1.4585 ± 0.0010 nm, b = 0.7331 ± 0.0005 nm, c = 0.4223 ± 0.0003 nm, are indicative of the composition (Cr1.04±0.08Fe0.96 ± 0.08)B. It was not possible to identify the phase(s) giving rise to a much weaker set of diffraction lines in the patterns. Of the two alloys used by Kraft and Flinn as standards, the one intended to be Cr2B was found to be a mixture of Cr2B and Cr5B3. The second, intended to be Cr1.0Fe1.0B was determined to be Cr0.67± 0.07Fe1.33± 0.07B.