钼粉表面化学镀铜工艺研究

采用化学镀方法对平均粒径3 μm的Mo粉末进行化学镀铜,探讨了工艺条件对化学镀铜的影响.利用扫描电镜(SEM)对钼粉镀覆前后形貌进行观察;X射线衍射(XRD)对所得复合粉末相组成进行了分析.结果表明:采用化学镀的方法可以成功地获得铜含量(质量分数)为15%～85%的Mo/Cu复合粉末,复合粉末中无Cu2O,表面平滑,但有团聚现象;化学镀铜过程中,pH值的临界值为12,随着pH值增加,镀速加快,但是pH值过高会引起甲醛分解,镀液中pH值的最佳范围在12～13之间;随着温度和甲醛含量的升高,镀速加快,镀液稳定性降低,镀液中甲醛含量和温度最佳范围分别为22～26 mL/L,60～70℃.     

化学镀工艺参数对制备铜包钨粉的影响研究

采用化学镀法制备铜包钨复合粉,通过前处理工艺、络合剂、还原剂、溶液的pH值以及温度等影响因素研究粉镀层的性能。研究结果表明化学镀铜在前处理工艺中必须要进行完全处理才能使得镀层稳定、均匀;使用络合剂酒石酸钾钠和EDTA-2Na相结合,可以既减少镀液中游离的铜离子提高溶液的稳定性,也可以在镀液稳定时间将铜离子完全沉淀,提高镀速,当络合剂EDTA-2Na和酒石酸钾钠质量比为1.2时,沉铜速率最快;还原剂甲醛和溶液的pH值也相互影响着镀液的稳定性,结果显示还原剂甲醛的最佳浓度为10~20 mL/L,pH值为12~13;反应最佳温度为45~55℃;制备的铜包覆钨复合粉表面的镀层均匀、连续、致密。     

新型环保型化学镀铜工艺

为了开发一种成本低廉、环境友好且镀层性能好的化学镀铜工艺,以草酸电解还原溶液为还原剂在A3钢表面进行化学镀铜。探讨了镀液组成、pH值及温度对镀铜速度、镀液稳定性及镀层附着力的影响。结果表明：最佳工艺为12～15g／L CuSO4,30～40g／LEDTA,10～20mg／L2,2’-联吡啶,10～12g／L乙醛酸＋5—...     

四羟丙基乙二胺和EDTA·2Na盐化学镀铜体系研究

为了降低成本、提高镀层质量和镀液的稳定性,以混合配位体(EDTA·2Na)代替THPED(四羟丙基乙二胺),系统研究了THPED和EDTA·2Na盐双配位体化学镀铜体系.对镀速、镀液稳定性及镀层附着力的研究结果表明,镀速随EDTA·2Na盐、硫酸铜和甲醛浓度的增加先升高后降低;随THPED浓度的增加先降低后升高;随溶液pH值和镀液温度增加而升高;添加剂亚铁氰化钾、α,α'-联吡啶和2-MBT虽均使镀速减慢,但能使镀层外观变好;聚乙二醇-1000(PEG-1000)对镀速影响较小,但能使镀层质量变好.其化学镀铜最佳条件为THPED 10.0 g/L,EDTA·2Na 8.7 g/L,CuSO4·5H2O 12.0 g/L,甲醛(37%～40%)16.0 mL/L,α,α'-联吡啶10.0 mg/L,亚铁氰化钾40.0 mg/L,PEG-1000 1.0 g/L,2-MBT(二巯基苯骈噻唑) 0.5 mg/L,pH值13.2及镀液温度50 ℃.在最佳条件下获得的镀层外观红亮、表面平整,镀液稳定,镀速达到4.05 μm/h.由SEM分析可知,镀层表面平整、光滑、晶粒细致.     

三乙醇胺和EDTA·2Na盐双络合体系快速化学镀铜T艺研究

系统研究了以三乙醇胺(TEA)为主络合剂、EDTA·2Na盐为辅络合剂的二次镀铜体系.实验结果表明镀速随EDTA·2Na盐浓度增加而减慢,随TEA浓度、硫酸铜浓度、甲醛浓度、溶液pH值和镀液温?快;添加剂亚铁氰化钾、α.α′-联吡啶和2-MBT均能使镀速减慢且浓度较低时均能使镀层外观变好;PEG-1000对镀速影响较小,但能使镀层质量变好.其二次化学镀铜最佳条件是:CuSO4·5H2O为16g/L,EDTA·2Na盐为6g/L,TEA为21.5g/L,pH值为12.75,甲醛(37%～40%)为16ml/L,亚铁氰化钾为100mg/L,α,α′-联吡啶为20mg/L,PEG-1000为1g/L,2-MBT为0.5mg/L及镀液温度为50℃.在最佳条件下镀速达到10.57μm/h,SEM分析镀层表面光滑、结晶均匀.     

硅粉表面化学镀铜工艺研究

研究了化学镀法对硅粉进行化学镀铜过程,探讨了甲醛含量、pH值、温度对化学镀铜反应时间及复合粉体颜色的影响和镀层的微观形貌及结构。结果表明：在镀液中,pH值增大、温度升高、甲醛含量增加,可以缩短反应时间,提高镀速。得出最佳工艺条件：甲醛为60～72ml／L,pH值为12～12．5,60℃。所得复合粉体镀覆均匀,晶形良好,没有Cu2O的存在。     

三乙醇胺和EDTA·2Na盐双络合体系快速化学镀铜工艺研究

系统研究了以三乙醇胺(TEA)为主络合剂、EDTA·2Na盐为辅络合剂的二次镀铜体系。实验结果表明镀速随EDTA·2Na盐浓度增加而减慢,随TEA浓度、硫酸铜浓度、甲醛浓度、溶液pH值和镀液温度的增加而加快;添加剂亚铁氰化钾、α。α′-联吡啶和2-MBT均能使镀速减慢且浓度较低时均能使镀层外观变好;PEG-1000对镀速影响较小,但能使镀层质量变好。其二次化学镀铜最佳条件是:CuSO4·5H2O为16g/L,EDTA·2Na盐为6g/L,TEA为21·5g/L,pH值为12·75,甲醛(37%~40%)为16ml/L,亚铁氰化钾为100mg/L,α,α′-联吡啶为20mg/L,PEG-1000为1g/L,2-MBT为0·5mg/L及镀液温度为50℃。在最佳条件下镀速达到10·57μm/h,SEM分析镀层表面光滑、结晶均匀。     

化学镀Ni-Cr-Cu-P合金工艺研究

化学镀镍磷合金镀层的耐蚀性已很难满足现代工业日益提高的防腐蚀要求,为提高其综合性能,拓宽应用范围,在化学镀镍磷合金液中加入硫酸铜和氯化铬制备镍铜铬磷四元合金镀层,优选出最佳工艺条件为:15 g/L硫酸镍,40 g/L次磷酸钠,0.2 g/L硫酸铜,0.5 g/L钼酸钠,0.5 mg/L稳定剂(由含氮有机化合物或含碘化合物配制而成),40 g/L配位剂(以一种多羟基羧酸作主配位剂,一种多元羧酸作辅助配位剂),20 g/L乙酸钠,10 g/L三氯化铬,表面活性剂(聚乙二醇和含氟表面活性剂) 适量,pH值4.0～5.0,温度80～90 ℃,时间20 min.研究了镀液中主要成分和工艺条件对合金镀层外观、沉积速度、耐蚀性的影响.检测了化学镀Ni-Cu-Cr-P合金镀层的性能,镀层中含8%～9%Cr,2%～3%Cu,78%～85%Ni.结果表明,所得的镍铜铬磷四元合金镀层结晶细致,达镜面光亮,其耐蚀性、孔隙率和硬度等性能均优于化学镀镍磷合金层.     

几种添加剂对陶瓷化学镀铜层性能的影响

陶瓷表面金属化处理的传统镀银工艺存在工艺复杂、设备投资大、成本高、耐焊及耐磨性不足等缺点,使用化学镀铜技术可以很好地解决上述问题.用电化学等方法,研究了添加剂亚铁氰化钾、2,2'-联吡啶和L-精氨酸对陶瓷化学镀铜镀液的沉积速度与稳定性、镀层的耐腐蚀性、导电性及结合力的影响.结果表明:用4%AgNO_3作为活化荆,代替价格昂贵的PdCl_2,效果较好.陶瓷镀铜最佳配方和工艺为:15 g/L硫酸铜,10 mL/ L甲醛,40 g/L酒石酸钾钠,pH值12.6,室温,施镀时间1 h,无搅拌.添加剂最佳使用量分别为:5mg/L亚铁氰化钾;5 mg/L 2,2'-联吡啶;10 mg/L L-精氨酸以及二元复合添加剂5 mg/L 2,2'-联吡啶+10mg/L L-精氨酸.所得陶瓷镀铜层呈现光亮的淡粉红色.     

化学镀Ni-Fe-P合金镀液组分及pH值对镀层性能的影响

目前,对化学镀Ni-Fe-P合金镀液影响镀层形成及其阴极极化曲线的研究较少。在纯铜片表面化学镀Ni-Fe-P合金;采用扫描电镜观察了镀层的形貌,采用能谱仪测试了镀层成分,采用X射线衍射仪分析镀层的结构,采用电化学工作站测试镀层在镀液中的阴极极化曲线;通过单因素法考察了镀液组分含量及pH值对化学镀Ni-Fe-P合金沉积速率、镀层成分、形貌、结构及阴极极化曲线的影响。结果表明:镀液各组分含量及pH值对镀层性能有较大影响;最佳工艺条件为20 g/L硫酸镍,12 g/L硫酸亚铁,30 g/L次磷酸钠,40 g/L柠檬酸三钠,20 g/L硫酸铵,20 mL/L乳酸,pH值9.0,镀液温度80℃,时间1 h;此条件下所得Ni-Fe-P合金镀层以非晶态形式存在,其耐蚀性能明显优于相同工艺条件制备的Ni-P镀层。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Certification Becomes Important for the I Quality; and Safety Supervision of the Chinese Liquor Sector

The end of 2007, over 200 unit products of more than 80 Chinese firms have passed the quality grade certification for liquor products. These products involve distilled spirits, beer, wine, yellow wine, fruit syrup wine and others, and cover over 80% of the national top-branded liquor products.……     

Deposition and Coating Properties on CVD Tungsten

Surface characterization and microstructure studies are performed on chemical vapor deposited (CVD) tungsten coating. There is about 2 μm thickness diffusion layer of tungsten in the molybdenum substrate. The thermal shock test shows tungsten coating has good adhesion with molybdenum substrate, but the elements of oxygen and carbon in the tungsten coating have the bad affection to the adhesion. The result of high-temperature diffusion experiment is the diffusion rate from molybdenum substrate to tungsten coating is faster.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Analysis of marine hydrobiont lipid extracts as possible cryoprotective agents

We studied a combined effect of the cryoprotectants both of lipid and carbohydrate origin at the presence of DMSO or without it on cell viability and the RNA synthesis in the embryonic mollusc and echinoderm cell cultures obtained at different developmental stages. Cryoprotective properties of exogenous lipids correlated with their thermotropic behavior. Lipid extracts from marine hydrobiontes, which thermal transitions are characterized by relatively small part of calorimetric thermogram area lying at temperatures above 0 °C (6–18%), were found to possess a considerable cryoprotective activity. The results are discussed in relation to the prediction of the cryoprotective activity of lipid extracts for marine animal cells. In addition, it was found that marine invertebrate cells can be cryopreserved without DMSO at the presence of trehalose and lipid extracts of some marine hydrobiontes.     

Low-Temperature Properties of Silver

Pure silver is used extensively in the preparation of high-temperature superconductor wires, tapes, films, and other configurations in which the silver not only shields the superconducting material from the surrounding materials, but also provides a degree of flexibility and strain relief, as well as stabilization and low-resistance electrical contact. Silver is relatively expensive, but at this stage of superconductor development, its unique combination of properties seems to offer the only reasonable means of achieving usable lengths of conductor. In this role, the low-temperature physical (electrical, thermal, magnetic, optical) and mechanical properties of the silver all become important. Here we present a collection of properties data extracted from the cryogenic literature and, to the extent possible, selected for reliability.