Sn—Ag基无铅焊料的研究与进展

研究开发无铅焊料是我国电子材料行业面临的新课题,Sn-Ag系是一种有希望替代铅焊料的无铅焊料。本文综述了该合金系研究的主要成果,包括微观组织、焊料与基体的相互作用、拉伸和剪切性能、疲劳性能及蠕变性能,指出了此合金系作为软钎焊材料尚待解决的问题。采用合金化、基体涂层、发展新焊剂等手段可使该合金系发展为较理想的无铅焊料。     

Microstructure and properties of unleaded free-cutting brass containing stibium

A new environmental friendly cutting brass containing stibium instead of lead was produced by casting and rolling. The microstructure was observed and the mechanical, dezincification and cutting properties were studied. The results show that the white particles distribute in both grains and grain boundaries, and the particles are mainly intermetallics containing stibium. The tensile strength, yield strength and elongation percentage of half-hard Sb-brass is 461.72 MPa, 213.3 MPa and 15.67%, respectively. Corresponding to HPb59-1 by the size as well as appearance of the chips and the mechanism of free-cutting, the cutting property of unleaded free-cutting Sb-brass is excellent. The unleaded Sb-brass has excellent dezincification corrosion resistance, and the average depth of longitudinal section is about 295.4 μm, while the average depth of lateral section is about 214.7 μm, and it is feasible to develop a new unleaded free-cutting Sb-brass.     

铌及铌合金高温抗氧化研究进展

铌及铌合金以其熔点高、耐腐蚀和良好的高温强度成为重要的高温结构材料。但高温抗氧化性能较差是制约其应用的关键问题。从铌的氧化机理、合金化抗氧化保护和表面涂层保护三方面，论述了铌及铌合金高温抗氧化的研究进展。分析了研究中面临的问题，并提出了解决途径。     

镁及镁合金环保型阳极氧化工艺研究

研究了镁及镁合金无铬、无磷的环保型阳极氧化工艺测定了镁阳极氧化的稳态伏安曲线和电流密度一时间曲线通过研究氧化电压、电解液中NaOH和Al(0H)3的浓度、电解液温度、氧化时间等对镁阳极氧化成膜的影响，确定了最佳工艺条件分析了最佳工艺条件下得到的镁合金氧化膜的成分、结构与表面形貌，并对镁合金基体与氧化膜的耐腐蚀性能进行了比较结果表明，在环保型阳极氧化液中得到的镁合金氧化膜由镁和铝的氧化物组成，其色泽光滑，结构致密，与镁合金基体相比硬度与耐腐蚀性能都大为提高。     

Internal oxidation thermodynamics and microstructures of Ag-Y alloy

The thermodynamic data of pure Ag and Y were calculated. The phase constitution, composition of micro-region and microstructures of Ag-Y alloy after internal oxidation were investigated by X-ray diffractometry(XRD), energy dispersion spectrometry(EDS) and scanning electron microscopy(SEM). The results show that the internal oxidation behavior of Ag-Y alloy is feasible from the view of thermodynamics. The upper limit of oxygen partial pressure of Ag-Y alloy oxidation is a function of temperature. Two phases (Ag and Y2O3) appear in Ag-Y alloy after the internal oxidation. The surface of Ag-Y alloy is convex because of the volume expansion of oxide in the alloy and the composition of the convex part is Ag. In Ag-Y2O3 sintered bulk Y2O3 particles are distributed inhomogeneously and conglomerated seriously, but they are dispersed uniformly in the Ag matrix after severe plastic deformation.     

15Cr2Ni3MoW穿孔顶头的组织形态初探

研究了15Cr2Ni3MoW合金钢金相组织演变过程及其组织形态,明确了该钢的组织形态特点和适应穿孔顶头高性能要求所应有的组织结构模式及与使用性能之间的关系。15Cr2Ni3MoW合金钢生产的顶头具有均匀细小的贝氏体和少量马氏体的复合组织,其表面氧化膜应致密,与基体结合牢固,并以FeO为主要成分。改进顶头的生产工艺后,顶头组织改善,硬度提高,冲击功提高45%,使用寿命提高50%以上。     

溶胶-凝胶法制备的ZnO:Al薄膜的微观结构及光学、电学性能

采用溶胶-凝胶法制备了ZnO:Al(AZO)透明导电薄膜．通过X射线衍射(XRD)、紫外-可见分光光度计 (UV-Vis)、扫描电镜(SEM)和电阻测量装置,考察了Al掺杂量、退火温度及镀膜层数等工艺参数对薄膜的微观结构和光电性能的影响．结果表明,退火温度越高,多晶AZO薄膜的(001)晶面择优取向生长的趋势越强,并且随退火温度升高,薄膜的晶粒尺寸增大,透光率增加．薄膜晶体结构为纯ZnO的六角纤锌矿结构．在掺杂浓度1％(摩尔分数)、退火温度500℃及镀膜层数10的条件下,得到了电阻率为3．2×10-3Ω·cm、可见光区的平均透射率超过90％的AZO薄膜．     

Morphology, structure and formation mechanism of silicide coating by pack cementation process

The MoSi2 coating on C 103 niobium based alloy was prepared by pack cementation method. The formative mechanism, morphology and structure of coating were investigated. The silicide coating was formed by reactive diffusion obeying parabolic rule during pack cementation process. It is found that the composite structural coating is composed of three inferior layers as follows. The main layer is composed of MoSi2, the two phases＇ transitional layer consists of NbSi2 and a few NbsSi3 and the diffuse layer is composed of NbsSi3. The dense amorphous glass layer formed on the surface at high temperature oxidation circumstance can effectively prevent the diffusion of oxygen into coating.     

微量Sc元素对AZ91镁合金组织性能的影响

本试验以AZ91镁合金为基,制备了含Sc的AZ91镁合金.研究了微量Sc对AZ91镁合金组织性能的影响.结果表明,Sc的加入,在AZ91中形成了Al3Sc新相;细化了AZ91合金的铸态组织,改变了第二相Mg17Al12的形貌;显著提高了材料的硬度、强度;抑制了材料的动态再结晶,且延缓了材料的时效硬化行为.     

Mo在水溶液中的耐腐蚀性能

综述了Mo在不同溶液中的电化学行为、电池作用腐蚀 行为，并从技术的角度总结了它在各种碱性溶液、酸性溶液、无机盐溶液以及海水中的耐蚀性能.最后对研究工作进行了展望.