印制板组装焊后清洗工艺

无论是有铅工艺还是无铅工艺,大多数EMS均采用免清洗技术,但对于要求比较严格的军用类、医疗器械类及汽车电子类生产厂家则仍然要求焊后清洗.作为军品类电子产品印制板组装件清洗后的洁净度满足GJB5807-2006军用印制板组装件焊后清洗要求:三级电子产品,用五倍放大镜检查印制板组装件表面应无残留物存在,印制板表面离子残留物含量不大于1.56μg(NaCl)/cm2.通过试验研究发现:在清洗剂一定的情况下,选用不同的焊膏,焊后清洗的效果不同;另外,焊接结束与清洗前间隔时间的长短,也是影响清洗效果的重要因素.采用Loctite CR37 63Sn37Pb和Alpha UP78 63Sn37Pb两种焊膏与VIGON A 200的水基清洗剂在焊后1 h之内进行清洗,可得到较好的清洗效果.     

新型常温水基金属清洗剂配方的研制

论述了一种新型清洗机专用常温洗涤水基金属清洗剂的配方组成，并对清洗剂的性能进行了测试。结果表明，该清洗剂去污力强，清洗效果好，清洗率达到98．5％以上，低泡，使用安全，尤其对碳钢具有良好的清洗和防锈性能。     

铝合金水基清洗剂的开发

开发了铝合金水基清洗剂,水基清洗剂以水代替有机溶剂,在保证清洗效果的前提下,降低了清洗成本,提高了铝合金产品表面质量,改善了生产环境,消除了生产安全隐患。     

矩形片式电阻半导体激光钎焊无铅焊点的热循环试验

选用Sn-Ag-Cu无铅钎料,采用半导体激光软钎焊和红外再流焊两种方法对0805型矩形片式电阻元件进行钎焊,并对采用不同方法得到的钎焊焊点进行热循环试验.结果表明,激光软钎焊矩形片式电阻焊点的力学性能优于传统红外再流焊工艺所获得的电阻焊点的力学性能;片式电阻焊点的剪切力随热循环次数的增加呈现下降趋势,在热循环次数相同时,激光软钎焊焊点的力学性能优于红外再流焊焊点.随着热循环次数的增加,片式电阻焊点的剪切断裂的方式由明显的韧性断裂逐渐向脆性断裂转变.     

超声波清洗技术的特点及应用

超声波清洗与其它清洗相比具有洗净率高、残留物少、清洗时间短、清洗效果好,凡是能被液体浸到的被清洗件,超声对它都有清洗作用.不受清洗件表面形状限制,如深孔、狭缝、凹槽,都能得到清洗.由于超声波发生器采用D类工作放大,换能器的电声效率高,因此超声清洗具有高效节能.它是一种真正高速、高质量、易实现自动化的清洗技术.若清洗剂采用非ODS清洗剂则具有绿色环保清洗作用.超声清洗对玻璃、金属等反射强的物体其清洗效果好,而不适宜纺织品、多孔泡沫塑料、橡胶制品等对声吸收强的材料.     

低温高效低泡水基冷轧铝板清洗剂的研究与开发

目的解决冷轧铝板在冬季常温清洗中,由于水温低造成水基清洗剂洗净率低、易发泡等问题。方法在3℃下研究了两种嵌段醇醚非离子表面活性剂的复配体系的去污性能及其清洗液的泡沫行为,以及羧酸胺缓蚀剂、烷基磷酸酯OPS75E的复配体系对钢材、铝材的缓蚀作用。结果开发了一种在低温下低泡、高效的水基铝板带清洗剂,最佳配方(以质量分数计):无水偏硅酸钠0.8%~2%,葡萄糖酸钠5%~8%,羧酸胺缓蚀剂2%~4%,OPS75E 1%~3%,PAA 1%~3%,有机胺酯TPP 3%~5%,NF7305 5%~8%,RPE31102%~4%,水63%~80.2%。在3℃及以上温度下,该清洗剂无泡,且能有效抑制清洗中由于油污皂化引起的泡沫,使用浓度3%、清洗时间2 min时,对冷轧铝带洗净率可达99%以上。结论该清洗剂清洗效果较好,对碳钢、铝材有很好的缓蚀性能,各项性能符合JB/T 4323.1—1999标准。     

高效水基金属清洗剂的研制

水基金属清洗剂由表面活性剂及多种添加剂组成。经复配实验发现,非离子表面活性剂：阴离子表面活性剂＝1：1－1：1．5（质量比）时,可获得较高的除油率。添加防锈剂B1或N1,P－M无铬钝化剂后,在不同的温度范围内有良好的清洗性和防锈性。     

输油管道废弃清洗剂技术现状和发展趋势探讨

随着油田产量下降和腐蚀风险，我国约3000多公里管道存在报废处置需求，《安全生产法》对管道清洗提出更高要求，管道清洗存在油蜡残余物风险较高。阐述了常用清洗剂、优缺点和适用条件，物理化学技术清洗剂性能不能保证管道清洗质量。研发新型高效报废管道清洗剂，室内测试清洗剂在15℃溶解速率为0.56mm/min，溶垢能力为1.1g/g，现场应用清洗效果良好。从清洗性能和安全环保方面阐述了未来高效清洗剂研究重点和发展趋势。     

某新型清洗剂在弹药弹筒表面漆膜清洗上的应用

目的用某新型清洗剂代替酒精、汽油应用于弹药弹筒表面漆膜清洗。方法选取先进、可靠、安全环保的某新型清清洗剂,应用于弹药弹筒表面漆膜中间过程中漆膜上的油污、汗渍、红丹、记号笔、药粉等污物的清洗。通过对弹药弹筒表面漆膜的特点、漆膜上各类污渍的组成以及对漆膜中间清洗工艺过程进行分析,同时针对上述特点,拟定清洗剂选用原则,结合清洗剂的组成、特点、除污机理,通过对清洗剂进行应用试验,从清洗剂安全性能、清洗后漆膜附着力性能、清洗后漆膜耐盐雾性能、清洗剂的清洗效果、清洗剂的挥发速度、清洗剂气味等几个方面进行试验。结果某新型清洗剂具备清洗效果好、挥发速度快、清洗效率高等优点,清洗后对弹药弹筒表面漆膜无影响,满足弹劳逸结合漆膜清洗质量要求。结论某新型清洗剂可以代替酒精和汽油在弹药弹筒表面漆膜清洗上进行应用,具有环保、无毒等特点,在弹药弹筒表面漆膜清洗应用领域具有推广意义。     

钛双极板表面原位生成TiN涂层的性能研究

目的降低钛合金表面的接触电阻,提高其抗腐蚀性能。方法 TA2纯钛表面进行活化后,原位反应生成TiN涂层。采用X射线衍射(XRD)、扫描电子显微镜(SEM)和能谱仪(EDS)分析表面形貌和成分,使用直流表面电阻和界面接触电阻(ICR)来评价涂层的导电性,在模拟质子交换膜燃料电池(PEMFC)环境中测试其抗腐蚀性能。结果经过TiN处理后的TA2纯钛双极板表面致密,其生长方式为沿(111)晶面择优生长。在750℃反应2 h获得的试样的直流表面电阻和ICR电阻最低,抗腐蚀性能最佳。压力为120N/cm^2时,电阻率稳定在6.7 m?/cm^2。在模拟PEMFC环境中的表面腐蚀电流为0.816μA/cm^2,经过恒电位扫描后的SEM显示,其表面完整,H2气氛中涂层界面完整,空气气氛中出现较多点蚀。结论在TA2纯钛表面原位反应生成TiN涂层有助于提高基体表面的抗腐蚀性和导电性。     

Effects of Post-weld Heat Treatment on Microstructure,Mechanical Properties and the Role of Weld Reinforcement in 2219 Aluminum Alloy TIG-Welded Joints

In as-welded state, each region of 2219 aluminum alloy TIG-welded joint shows diff erent microstructure and microhardness due to the diff erent welding heat cycles and the resulting evolution of second phases. After the post-weld heat treatment, both the amount and the size of the eutectic structure or θ phases decreased. Correspondingly, both the Cu content in α-Al matrix and the microhardness increased to a similar level in each region of the joint, and the tensile strength of the entire joint was greatly improved. Post-weld heat treatment played the role of solid solution strengthening and aging strengthening. After the post-weld heat treatment, the weld performance became similar to other regions, but weld reinforcements lost their reinforcing eff ect on the weld and their existence was more of an adverse eff ect. The joint without weld reinforcements after the post-weld heat treatment had the optimal tensile properties, and the specimens randomly crack in the weld zone.     

新型的治疗阿尔茨海默氏症药物(1-二甲基磷酰基-2,2,2-三氯)-乙基-1-醇烟酸醋对体外神经细胞的作用

目的: 观察本实验室合成的一种治疗阿尔茨海默氏症(AD)的药物(1-二甲基磷酰基-2, 2, 2 -三氯)-乙基^-1-醇烟酸醋(NMF),对体外培养的皮层神经细胞活性的影响以及对海人藻酸(KA)所致的神经损伤的保护作用。方法: 采用体外培养皮层神经元的方法,解剖分离 15 d胚胎小鼠皮层神经细胞, 接种于 96孔板,48 h 后加药并培养 72 h,以 MIT 法 观察 NMF 对小鼠皮层神经细胞活性的影响;同时将接种于 24 孔板的细胞预先给予 NMF,d 3 时加或不加KA处理后,以台盼蓝染色鉴别并计数死、活细胞,可得出细胞的存活率。结果: NMF 明显促进胎鼠皮层神经元活性,其中 NMF1、0. 1、10nmol·L^-1促进神经元活性增殖率分别高达 34.7%、37.4%、36. 7%, NMF 明显促进正常胎鼠皮层神经元存活卒,与对照组比较,10nmol·L^-1 NMF 对皮层神经元的存活率分别提高 39.3%、73.5%。 NMF能显著 对抗 KA 所致的神经元损伤,与 KA 损伤组相比, NMF0.1、10、10nmol·L^-1对损伤皮层神经元的保护率分别为 77.30%、80.10%、84.15%。结论: NMF 明 显促进胎鼠皮层神经元的洁性、提高正常皮层神经元,的存活卒,并能有效地保护KA所致的神经元损伤,提示 NMF 是一种很有潜力的治疗 AD 的药物。     

The First Phase of the SRIF Industrialized Base in ＂West Area＂ Has Been Put into Operation

After nearly two years＇ tense construction, the first phase of industrialized base of Shenyang Research Institute of Foundry （SRIF）, located at the Tiexi Casting and Forging Industrial Park in the west of Tiexi District, has now been completed and formally put into operation.     

THERMODYNAMICS STUDY ON THE DECOMPOSITION OF CHROMITE WITH KOH

Institute of Process Engineering, Chinese Academy of Sciences, China, has proposed a method for oxidative leaching of chromite with potassium hydroxide. Understanding the mechanism of chromite decomposition, especially in the potassium hydroxide fusion, is important for the optimization of the operating parameters of the oxidative leaching process. A traditional thermodynamic method is proposed and the thermal decomposition and the reaction decomposition during the oxidative leaching of chromite with KOH and oxygen is discussed, which suggests that chromite is mainly destroyed by reactions with KOH and oxygen. Meanwhile, equilibrium of the main reactions of the above process was calculated at different temperatures and oxygen partial pressures. The stable zones of productions, namely, K2CrO4 and Fe2O3, increase with the decrease of temperature, which indicates that higher temperature is not beneficial to thermodynamic reactions. In addition, a comparison of the general alkali methods is carried out, and it is concluded that the KOH leaching process is thermodynamically superior to the conventional chromate production process.     

INFLUENCE OF HEAT TREATMENT ON DAMPING BEHAVIOUR OF THE MAGNESIUM WROUGHT ALLOY AZ61

The effect of isochronal heat treatments for 1h on variation of damping, hardness and microstructural change of the magnesium wrought alloy AZ61 was investigated. Damping and hardness behaviour could be attributed to the evolution of precipitation process. The influence of precipitation on damping behaviour was explained in the framework of the dislocation string model of Granato and Lücke.     

Theoretical Analysis for the Motion and Temperature of Melt Droplets in Spray Degassing Process

The motion of melt droplets in spray degassing process was analyzed theoretically. The height of the treatment tank in spray degassing process could be determined by the results of theoretical calculation of motion of melt droplets. To know whether the melt droplets would solidify during spraying process, the balance temperature of melt droplets was also theoretically analyzed. Then proof experiments for theoretical results about temperature of melt droplets were carried. In comparison, the experimental results were nearly similar to the calculation results.     

Growth Kinetics of Single Inclusion Particle in Molten Melts

On the basis of the single-particle framework, a new theory on inclusion growth in metallurgical melts is developed to study the kinetics of inclusion growth on account of reaction and collision. The studies show that the early growth of inclusion depends on reaction growth and Brawnian motion collision, and where the former is decisive, the late growth depends on turbulence collision and Stokes＇ collision, and where the former is dominant; collision growth is very quick during the smelting process, lessened in the refining process, but nearly negligible in the continuous casting process.     

Three-Dimensional Growth of Coherent Ferrite in Austenite: A Molecular Dynamics Study

Coherent second phase often exhibits anisotropic morphology with specifi c orientations with respect to both the second and the matrix phases. As a key feature of microstructure, the morphology of the coherent particles is essential for understanding the second-phase strengthening eff ect in various industrial alloys. This letter reports anisotropic growth of coherent ferrite from austenite matrix in pure iron based on molecular dynamics simulation. We found that the ferrite grain tends to grow into an elongated plate-like shape, independent of its initial confi guration. The fi nal shape of the ferrite is closely related to the misfi t between the two phases, with the longest direction and the broad facet of the plate being, respectively, consistent with the best matching direction and the best matching plane calculated via the Burgers vector content(BVC) method. The strain energy calculation in the framework of Eshelby's inclusion theory verifi es that the simulated orientation of the coherent ferrite is energetically favorable. It is anticipated that the BVC method will be applicable in analysis of anisotropic growth and morphology of coherent second phase in other phase transformation systems.     

An Easy Way to Quantify the Adhesion Energy of Nanostructured Cu/X(X=Cr,Ta,Mo,Nb,Zr) Multilayer Films Adherent to Polyimide Substrates

An approach based on film buckling under simple uniaxial tensile testing was utilized in this paper to quantitatively estimate the interfacial energy of the nanostructured multilayer films(NMFs) adherent to flexible substrates. The interfacial energies of polyimide-supported NMFs are determined to be *5.0 J/m2 for Cu/Cr, *4.1 J/m2 for Cu/Ta,*2.8 J/m2 for Cu/Mo, *1.1 J/m2 for Cu/Nb, and *1.2 J/m2 for Cu/Zr NMFs. Furthermore, a linear relationship between the adhesion energy and the interfacial shear strength is clearly demonstrated for the Cu-based NMFs, which is highly indicative of the applicability and reliability of the modified models.     

High-Speed Friction Stir Welding of SiC_p/Al–Mg–Si–Cu Composite

A 17 vol% SiCp/Al–Mg–Si–Cu composite plate with a thickness of 3 mm was successfully friction stir welded(FSWed) at a very high welding speed of 2000 mm/min for the first time. Microstructural observation indicated that the coarsening of the precipitates was greatly inhibited in the heat-affected zone of the FSW joint at high welding speed, due to the significantly reduced peak temperature and duration at high temperature. Therefore, prominent enhancement of the hardness was achieved at the lowest hardness zone of the FSW joint at this high welding speed, which was similar to that of the nugget zone. Furthermore, the ultimate tensile strength of the joint was as high as 369 MPa, which was much higher than that obtained at low welding speed of 100 mm/min(298 MPa). This study provides an effective method to weld aluminum matrix composite with superior quality and high welding efficiency.