Effects of sodium tungstate on characteristics of microarc oxidation coatings formed on magnesium alloy in silicate-KOH electrolyte

Oxide coatings on AM60B magnesium alloy were prepared using the microarc oxidation（MAO） technique in silicate-KOH electrolyte with addition of 0-6.0 g/L Na2WO4. The MAO processes in base electrolyte with different concentrations of Na2WO4 were studied. The microstructure, compositions and mechanical tribological characteristics of the oxide coatings were also investigated by SEM, XRD, XPS, microhardness analysis and ball-on-disc friction testing, respectively. It is found that the addition of Na2WO4 into the base electrolyte has direct effect on the characteristics of voltage-time curves and breakdown voltage in MAO process. The number of micropores at top of the coating surface is increased by the addition of Na2WO4. The fraction of forsterite Mg2SiO4 in the oxide coating increases with increasing concentration of Na2WO4 in base electrolytes. Furthermore, the microhardness and wear resistance of oxide coatings are enhanced as well.     

Effect of rolling and heat treatment on microstructure and properties of Ti-26 sheet

The effect of heat treatment and rolling process on the properties and microstructures of Ti-26 （Ti-15V-3Al-3Cr-3Sn-Forming） sheet was studied. The results show that the best rolling temperature for Ti-26 alloy is in the temperature range from 900 ℃ to 950℃. Under this condition, the resistance of deformation and yield ratio are low and the alloy has better hot work ability. The alloy will achieve better mechanical properties and completely recrystallized β microstructure when the deformation ratio is not less than 60% and the solution temperature is 30 ℃ above the phase transformation temperature. The best heat treatment conditions are recommended as： 790℃, 30 min, AC or WQ followed by 510 ℃, 10 h, AC. Under this heat treatment condition the strength of the Ti-26 alloy is 1 230 MPa and the elongation is 15%.     

Principles and application of RES welding technology

Friction element welding technology is rich of flow drill screws combined with friction welding technology and is developed for the hot-forming steel plate and aluminum alloy welding of car body-in-white. In this paper, the principle of RES welding technology, equipment, technical characteristics, application condition and welding parameters are analyzed systematically. Moreover, the changing laws of welding parameters and welded joint quality control standards are described, which provides the necessary technical support for safety and light-weight car body design requirements. This study has high practical application value, and enriches the automobile body joining technology.     

绿色银光釉的研制

一、前言 随着人们生活水平和欣赏情趣的提高,对居住环境的美化和装璜也越来越考究,这就给建筑陶瓷的设计和生产提出了更高的要求。陶瓷制品表面的装饰方法有许多种,金属化技术近几年受到广泛的重视。目前,形成金属化的方法有三种:(1)在陶瓷坯体上直接溅射熔融层;(2)在陶瓷制品釉面上涂以含有金属或金属化合物粉末的涂层,经过还原热处理,形成金属化装饰层;(3)配以特种组成的釉.随同制品烧成时,产生具有金属色调和光泽等外观性能的釉。用前两种方法生产的金属化装饰的釉面砖已经问世,但是,由于该两项技术对设备的现代化要求较高,加上再装     

关于CAPP系统中零件分组的探讨

文章结合ＳＪＣＡＰＰ系统开发实践，探讨零件分组的方法，提出以视检法为主并结合编码分类法是零件分组中一种高效实用的方法，取得满意的效果。     

关于线性工程压覆矿产资源量估算方法的探讨——以国道107线某段拟压覆矿产资源为例

本文以国道107线绕信阳市区一级公路某段压覆矿产资源为例,探讨了建设项目压覆矿产资源储量的估算方法.计算线性工程压覆矿山范围,采用垂直剖面法更加直观易懂,根据线性工程的形态与矿体走向合理布置剖面,分析压覆区地质特征确定移动角等参数,通过垂直剖面法圈定压覆范围,估算压覆矿产资源储量.其结果表明此种方法可行可靠,对同类线性...     

高质量的干净极限与脏极限MgB_2超导薄膜

利用混合物理化学气相沉积法(hybrid physical-chemical vapor deposition),在0001取向的SiC和Al2O3上原位制备了高质量的c轴外延MgB2薄膜,样品具有高于41K的零转变温度,超导剩余电阻率ρ(42K)<0.5μΩcm,很好地吻合第一原理计算的干净极限行为。X射线相分析图谱上没有MgO的衍射峰出现说明这种方法极大程度上避免了MgB2制备过程最易出现的氧污染。较高的磁电阻和低温低场条件下不存在磁通跳跃都说明了样品非常干净。借助一种改进的双加热丝装置,我们在干净MgB2样品基础上实现了可控的碳掺杂,掺碳后的样品超导临界温度下降,剩余电阻率升高,电子平均自由程由于杂质散射作用的增强而得到显著抑制,为符合脏极限的超导样品。     

表面活性剂对Ni-SiC复合电镀的影响

以瓦特型镀镍液为母液,在一定的工艺条件下复合电沉积Ni-SiC镀层,选用三种典型表面活性剂,即非离子型表面活性剂OP-10,阳离子型十六烷基三甲基溴化铵(CTAB),以及阴离子型十二烷基苯磺酸钠(LAS),通过对比实验,研究了它们对Ni-SiC复合电镀的影响,结果表明,LAS能显著改善镀层的表面质量,但对粒子复合量的贡献不大;OP-10能显著提高镀层的粒子复合量和硬度;CTAB能有效提高SiC颗粒的悬浮性能,促进SiC粒子与金属镍的共沉积.     

湿陷性黄土地区水泥厂建构筑物的地基处理与基础设计

湿陷性黄土地区的建构筑物地基按照建筑的用途与荷载需进行适当的地基处理，并选择合适的基础形式。本文通过对齐胜工贸公司年产15万吨粉磨工程中各子项的设计实例，提出了对于各类水泥厂的典型建构筑物在湿陷性黄土地区适当的处理方法。