抑制硬质合金中金属W、Co水解的复合防锈剂研究

采用工业上常用的几种水基加工液防锈添加剂对纯钴片和硬质合金刀具在常温下进行浸泡实验,用纯钴片和钨片做电极与饱和甘汞电极组成原电池测定电动势,根据电动势的大小结合电镜扫描分析判断不同防锈剂溶液对金属Co、W的溶解浸出情况。优选出抑制金属Co、W浸出效果好的防锈剂,将其按不同的比例复配进行电化学测定实验。实验结果表明:苯并三氮唑和钼酸钠对金属Co、W的浸出有明显的抑制作用。     

对硝基苯甲酸三乙醇胺酯对Co及WC的氧化溶解研究

以对硝基苯甲酸及三乙醇胺为原料,通过溶液共聚技术合成一种新型防锈润滑剂。通过电导率测定并结合场发射扫描电镜能谱分析技术研究该防锈剂对Co和WC的氧化溶解程度。实验结果表明:对硝基苯甲酸与三乙醇胺的摩尔比为1︰1.1时,合成的酯对Co的浸出有较好的抑制作用;同时,对降低WC的氧化溶解程度也具有较好的效果;随着温度的升高,Co的浸出较严重,而碳化钨的氧化溶解程度不明显。     

硬质合金刀具钴和碳化钨的浸出研究

硬质合金刀具在高速切削时,必须使用水基加工液。然而发现使用时水基加工液会使硬质合金中的钴、碳化钨浸出。本文通过浸泡试验,借助于扫描电镜和能谱分析,研究了不同温度时三乙醇胺溶液、碳酸钠溶液和苯并三氮唑溶液对硬质合金刀具中钴和碳化钨浸出的影响。实验结果表明:三乙醇胺溶液对硬质合金刀具中的钴有浸出的作用,常温下钴的浸出率为17.32%,随着温度的升高浸出作用明显,150℃时钴的浸出率为47.72%;碳酸钠溶液对硬质合金刀具中碳化钨有浸出作用,常温下钨的浸出率为13.28%,随着温度的升高,碳化钨的氧化溶解加剧,钨元素的浸出更加明显,150℃时钨的浸出率为45.59%;苯并三氮唑溶液对硬质合金中的钴无浸出作用,对硬质合金中的钨浸出作用不明显,150℃时钨的浸出率为1.28%。     

加压浸出脱除钴白合金中金属铜和钴的研究

阐述了采用加压浸出方法对金属铜和钴进行有效脱除。实验结果表明：加压浸出过程的较佳反应条件为反应温度150℃、硫酸浓度30 g/L、反应压力1.5 MPa、反应时间6 h、液固比6：1。在此反应条件下,金属Cu、Co的浸出效率分别达到了90％和88％。     

从湿法炼锌锑盐净化钻渣中回收钴、锌、镉、铜

在湿法炼锌工艺中,采用锑盐除钴法产出的净化钴渣经过酸性浸出后,锌、镉、钴等有价金属进入溶液,铜进入浸出渣。浸出液经过双氧水氧化除铁、低温锌粉置换除铜后,用α-亚硝基-β-萘酚的碱性溶液进行沉钴,沉钴渣经过酸洗除杂后,进行氧化焙烧而得粗Co2O4。该工艺,经济效益明显。     

电解浸出废旧锂电池中钴的热力学和动力学

以废旧锂电池正极条为阴极,以铅板作阳极,在稀硫酸溶液中,电解浸出正极材料中的钴,从热力学和动力学两方面对钴的电解浸出过程进行研究。实验及热力学数据分析表明:LiCoO2主要通过Co(OH)3还原浸出得到Co2+,考查浸出温度和时间表明在电解前期5~30 min电解浸出由缩核模型的化学反应过程控制,浸出率α与时间t满足未反应核收缩模型1-(1-α)1/3=Kt,其表观活化能为7.32 kJ/mol;中期是混合控制;后期75~180 min符合内扩散控制模型1-2α/3-(1-α)2/3=Kt,表观活化能17.05 kJ/mol。浸出液中的铝主要是铝箔表面氧化铝层不受阴极保护而溶于硫酸溶液,正极材料从铝箔上剥离与氧化铝层的溶解有关,剥离时间影响钴的浸出率。     

从低冰镍中高效浸提Ni、Cu、Co

以低冰镍为研究对象,采用FeCl_3-HCl溶液体系高效浸提目标金属Ni、Cu、Co,系统地研究FeCl_3溶液的浓度、盐酸溶液的浓度、浸出温度和时间对Ni、Cu、Co浸出率的影响,并对Ni的浸出动力学进行探讨。结果表明:在最优浸出条件下,即FeCl_3溶液的浓度为1.0 mol/L、盐酸溶液的浓度为0.5 mol/L、浸出温度90℃、浸出时间7 h时,Ni、Cu、Co浸出率分别达到98.4%、98.9%和97.3%。当温度为60~90℃时,Ni的浸出反应符合未反应核收缩模型,代入动力学方程分析后发现,Ni浸出反应过程是界面化学反应控速,表观活化能为38.4kJ/mol。     

MFC-MEC生物电化学耦合系统回收钴

为回收含Co(Ⅱ)溶液中的金属钴,以微生物燃料电池(Microbial fuel cell,MFC)降解有机物产生的电能驱动微生物电解池(Microbial electrolysis cell,MEC),实现MFC-MEC耦合系统自驱动运行。同时,在MEC的阴极还原Co(Ⅱ),研究不同MEC阴极电极材料、pH值以及电极极距等条件对Co(Ⅱ)处理的影响。结果表明:以碳纸为MEC阴极电极材料时,可得到较小的内阻1359.6?,库伦效率C_E和阴极效率η_(ca)分别为33.1%和21.6%,钴比收率为2.99 gCo/gCOD,阴极Co(Ⅱ)去除率为62.5%;MEC阴极液pH为3时,η_(ca)为43.9%,钴比收率为0.73g Co/g COD,Co(Ⅱ)去除率为88%;MEC极距为16cm时,可得到较高的阳极库伦效率20.5%和钴比收率0.85g Co/g COD,阴极Co(Ⅱ)去除率可以达到97.4%。经XRD分析,阴极产物为金属钴。     

无钴AB_5合金与纯钴的协同效应

采用电弧熔炼法制备出不含Co的AB_5型储氢合金,并将其与纯钴粉按不同质量比复合制成复合电极。采用XRD分析了AB_5合金的相结构,使用恒流充放电测试、循环伏安测试以及交流阻抗测试来研究复合电极的电化学性能。结果表明,当无钴的AB5储氢合金与纯钴粉按质量比为1∶5复合时,复合电极的性能最佳,其最大放电容量为534.7mAh/g,循环充放电50次之后的容量保持率为69.6%。复合电极AB_5∶Co=1∶5充放电时主要发生Co与Co(OH)_2之间的氧化还原反应,AB5的存在对Co的放电起着催化作用,促进了Co/Co(OH)_2反应,放电容量明显增加。     

碳化钨硬质合金的耐腐蚀性

我们用一种硅胶水溶液料浆对由钴、镍和铬混合物组成的具有不同粘蛄相的碳化钨系列硬质合金进行了耐腐蚀试验。运用电动势技术研究了这些硬质合金的极化特征。粘结剂成份的不同会影响硬质合金的属性及耐腐蚀性能，还影响耐腐蚀性的协合效应。纯镍粘结剂本身所固有的抗腐蚀性并不会增加硬质合金的耐腐蚀性，但与纯钴粘结剂牌号相比较，我们发现镍—铬—钴牌号更适合用来改进耐腐蚀性能。本文对含Ni—Cr—Co基粘结剂硬质合金和纯粘结剂金属牌号的性能及特性进行了比较，纯金属牌号的成份与相应硬质合金粘结相的成份相近。还解释了与成份和机械性能相关的特性的差别。     

Metallic dental materials in patient's oral cavity acting as electrodes of electrochemical cells

The work was aimed at studying of standard potentials of commonly used metallic dental materials and determining of the effect of saliva conductivity and reaction on value of the potentials. The following materials have been examined: gold alloy (a material used for crowns and bridgeworks), chromium‐cobalt alloy (for frameworks in removable partial dentures), and silver amalgams (used for fillings) manufactured by three different companies. Taking into account that mucosa makes one of the electrodes existing in oral cavity the rest potentials of mucosa have been in vivo measured in several patients. Their values, converted with respect to NHE, oscillated within the range from + 0.31 V to + 0.47 V. Among metallic dental materials examined in the experiment maximal standard potential was found for the gold alloy, further materials having lower potentials, in decreasing order, were chromium‐cobalt alloy, and the amalgams Amalcap Plus, ANA 2000 and Septalloy. Significant differences between standard potentials of examined materials and mucosa indicate spontaneous formation of galvanic cells of electromotive force reaching even about 0.6 V.     

EFFECT OF ELECTROLESS PLATING COBALT UPON CHARACTERISTICS OF NICKEL HYDROXIDE ELECTRODE FOR RECHARGEABLE ALKALINE BATTERIES

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回炉调电势B型热偶丝的热电特性研究

研究了B型热偶丝回炉调整热电势后,热电特性的变化规律.探讨了热偶丝热电势的均匀性以及线性变化趋势、调整热电势数据的偏差、调整PtRh30热电势和PtRh6热电势对配对热电势影响的区别等,并从材料性能和工艺环节等方面分析了引起这些变化的原因.     

A microscopic and impedance spectroscopy study of Finemet-Co amorphous alloys

Structural characterization of some Finemet-Co alloys is performed by scanning and transmission electron microscopies. The results show a response independent of the composition and state. In addition to this, electrode impedances were measured in 0.5 N KOH water solution. Three time constants were found for the electrode reaction at open circuit potential. The effect of cobalt addition was analyzed as well as the influence of the thermal treatment (TT). The values of the different parameters indicates that both, the substitution of iron by cobalt and the TT result in the increase of the stability of the oxide layers.     

基于滑模和自适应控制的无位置传感器PMSM换相研究

永磁同步电机(PMSM)无位置传感器控制系统是目前电机控制领域研究热点。针对无霍尔传感器的电机换相控制,提出采用滑模控制检测反电动势过零点,完成电机换相。为了得到精确的反电动势观测值并且减弱滑模控制的抖振现象,构建一种新型切换函数代替传统符号函数。应用李雅普诺夫稳定性理论,对滑模控制中的增益进行计算。为了解决转速计算中,因为求导微分环节影响PMSM转速控制,应用自适应算法计算转速。通过仿真和实验分析,验证所提方案能够准确得到PMSM反电动势和转速,实现PMSM精确换相控制。     

Effect of sintering additive and low temperature on the electrode polarization of CGO

Ceria-based materials were prepared by freeze-drying precursor route and calcined at low temperature to obtain nanometric powders. Sintered pellets were prepared after calcining cylindrical discs at 1400–1600 °C. The addition of small amounts of cobalt to the starting powders allowed us to obtain dense samples at temperatures as low as 1000 °C. The effect of temperature in cobalt-doped samples was also analyzed after sintering at 1150 and 1500 °C. Symmetrical Pt-electrodes were placed on both surfaces of the samples and impedance spectroscopy was used to study the electrode polarization in the temperature range of 500–1000 °C. Estimation of p-type electronic contribution was provided by the ion-blocking/Hebb-Wagner technique under oxidizing conditions. The results revealed that the addition of cobalt produce an important decrease in the electrode polarization, probably due to the onset of significant p-type electronic conductivity, thus extending the effective location of electrode reaction from triple metal–ceramic–gas contacts to larger interfaces. Other results showed certain correlations between the grain boundary behaviour and electrode polarization for samples with and without the sintering aid. The increase of the sintering temperature spoils the positive effects of the sintering additive on grain boundary conductivity and causes higher electrode polarization. Furthermore, the decrease of the lanthanide additive content also harms the ionic grain boundary conduction and the electrode polarization.     

导电基底表面钴基纳米材料的合成及其对丙酮酸浓度的检测

采用简便无模板的溶剂热法,直接在氧化铟锡导电玻璃(indium tin oxide,ITO)表面上制备高质量的絮状金属钴纳米球,研究了晶种Ru的沉积和前驱体醋酸钴的浓度等,对金属钴纳米球的形貌和大小的影响;利用CV,SEM和EDS分析对钴纳米球进行了形貌的分析和成分表征.用电化学方法对产物进行处理后,得到了六角片状的氢...     

First‐principles study on influence of alloying elements on electrochemical stability of cobalt‐base alloys

The paper studies the impact of the metal elements Nb, Ta, Zr, Mo, W, Al, Si, and Y on electrochemical stability of non‐passivated cobalt‐base alloys by evaluating the chemical potential and the electrode potential shift relative to pure cobalt metal using first‐principles calculations. Nb, Ta, and Si are found to make the surface Co atoms more stable on the {0001} surfaces of the corresponding alloys compared to pure Co {0001} surfaces, whereas Al, W, Mo, Y, and Zr make Co atoms less stable. Among all the considered alloying elements, niobium is the most beneficial to the stability enhancement of alloys. Furthermore, the effects of water adsorption on the electrochemical stability are considered. It is found that the surface adsorption properties may be considerably modified by introducing the Nb atoms. Our results indicate that water adsorption destabilizes both the alloy and pure metal surface. However, the Co? Nb alloy surface is still more stable than the pure Co surface in the presence of absorbed water. Our calculation reveals that the electrochemical stability of the Co? Nb alloy is sensitive to water molecular adsorption in comparison with that of the pure Co metal.     

Study on Coercive Force of Metallic Cobalt Powder

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