The effect of soft bake on adhesion property between SU‐8 photoresist and Ni substrate by molecular dynamics simulation

SU‐8 photoresist is a negative, epoxy‐type, near UV photoresist and is commonly used in micro electro mechanical systems (MEMS) and other thick resist application fields. However, poor adhesion strength between SU‐8 photoresist and metal substrate makes it difficult to bind, even contributes to the lithography failure. This significantly restricts the improvement of image resolution and depth‐to‐width ratio. As soft bake temperature and time are important for the interfacial adhesion property, in this article, molecular dynamics (MD) simulation was performed to investigate the effects of these two parameters on adhesion property between SU‐8 photoresist and Ni substrate. According to the adsorption theory, the simulation results were analyzed and validated by experiments. It is shown that with increasing soft bake temperature the adhesional work firstly increases and then decreases, and with increasing soft bake time the adhesional work decreases. This study provides theory basis for the confirmation of soft bake parameters. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Influence of Thermo‐Mechanical Processing Parameters and Chemical Composition on Bake Hardening Ability of Hot Rolled Martensitic Steels

In recent years, the increasing demand for advanced high‐strength steels (AHSS) has mainly been driven by the automotive industry and the need to reduce weight and to improve safety. Besides good ductility and high strength, AHSS have a high bake hardening and ageing effect, giving additional contribution to the strength of structural parts, subjected to the paint baking process. This paper investigates their bake hardening behaviour in dependence of hot rolling parameters and chemical composition, however, focussing on martensitic steels. Tosimulate the finishing steps of the hot rolling process with slight changes in reduction and temperature and their influence on the final mechanical properties of hot rolled martensitic steels, different thermo‐mechanical paths were applied. The increase in strength due to bake hardening was determined for different thermo‐mechanical schedules. Additionally, samples of different chemical compositions within the characteristic industrial tolerance range were studied under variation of pre‐load conditions, simulating the thermo‐mechanical hot rolling process. The samples were then subjected to bake hardening to study the varying chemical composition on this effect. Furthermore, the local use of bake hardening and ageing in hot rolled multiphase steels was investigated. It could be shown that characteristic values integrally describing the ageing effect, depend on the deformation path and the degree of pre‐strain, as well as on temperature and duration of the subsequent heat treatment. This partial ageing is stable and has a potential to be used for local strengthening of the steels.     

Evolution of appearance profile of hot-dip galvanized car-body steel sheet during deformation process

In recent years,the waterborne free intermediate coating process has been widely used in the automotive industry.Because the baking times and coating thickness are decreased,the surface covering capability of the painting process is reduced,which directly affects the appearance quality (long-and short-wave values) of the body paint.Thus,there are correspondingly higher requirements for the white body surface profile prior to painting.The surface profile of the white body is mainly affected by the plate material,the surface profile,and the deformation process.So,the change rule for the surface profile during deformation of the steel plate is a key factor in coating appearance optimization.In this paper,we first analyze the typical deformation of the outer cover of a car body.Then,we examine the change tendency of the surface profile of steel plates with respect to different deformation rates,specifically for a steel plate comprising a hot-dip galvanized bake-hardened steel sheet.Based on our analysis of the influence of the deformation on the coating appearance,we selected 3％,5％,and 8％ deformation rates in this research.We found the roughness (Ra) value in the typical deformation range (3％-8％) of the car body to exhibit a decreasing trend at first and then an increasing trend.The Ra value of the 8％ deformation is not more than the original plate test value.When the Pc value of the original plate is in the lower range (about 60),it exhibits a slight increasing trend in the deformation process (3％-8％).And when the Pc value of the original plate is in the higher range (about 120),it exhibits no increasing trend in the deformation process (3％-8％).In contrast,the waviness (WCA) value in the car body's typical deformation range (3％-8％) shows a significant growth trend.     

PEPSET和呋喃树脂自硬砂工艺性能对比研究

目的　研究铸铝件用ＰＥＰＳＥＴ 树脂自硬砂和呋喃树脂自硬砂的工艺性能． 方法　对比两种造型制芯材料常温性能和高温性能的实验研究方法． 结果　通过实验获得两种树脂自硬砂的工艺参数, 并就两种自硬砂的硬化速度、硬透性、发气性等的实验结果曲线进行对比分析． 结论　ＰＥＰＳＥＴ 树脂自硬砂工艺性能良好, 可望成为树脂自硬砂工艺的一个重要的发展方向．     

不同Mg/Si比对含Zn的Al-Mg-Si合金再结晶组织及性能的影响

为改善Al-Mg-Si系合金汽车板综合性能,通过浇铸法制备出3组合金成分铸锭,并经过均匀化、热轧、中间退火、冷轧,获得1 mm厚的合金板材.合金板材经560℃固溶30 min后,立即在100℃条件下预时效8 h,室温停放14天,模拟铝板转运存储过程,并拉伸变形2%,再在185℃下进行20 min烘烤处理,实现烘烤硬化.采用金相显微镜、装备电子背散射衍射的扫描电镜对合金进行显微组织观察及织构分析,通过万能电子试验机进行力学性能测定,研究不同Mg/Si比和高Zn元素对合金再结晶组织及织构、烘烤硬化性以及腐蚀敏感性的影响.结果表明,Mg/Si比相等合金再结晶组织更加均匀细小,平均晶粒尺寸190μm,存在相对较少的Cube织构{001}100和较多的P型织构{011}122;高Mg合金、高Si合金局部晶粒粗大,Cube织构{001}100较多,P型织构{011}122较少;预时效后,Mg/Si比相等合金强度较高,且烘烤硬化性优异,烤漆硬化增量达到107 MPa;烤漆后,更多的Zn原子扩散到晶界上,强化晶界微电流反应,欠时效态Mg/Si比相等合金较高Mg合金、高Si合金抗腐蚀敏感性降低,被腐蚀深度为121μm.     

Ti+Nb和Ti+V超低碳烘烤硬化钢的组织和性能研究

采用Gleeble-1500热模拟试验机对Ti+Nb和Ti+V复合处理超低碳BH钢的变形抗力和动态连续冷却转变进行研究,并观察了两种实验钢在不同冷却工艺条件下的金相组织。结果表明:在1100℃、应变速率1s-1时Ti+Nb超低碳BH钢的变形抗力比Ti+V超低碳BH钢高出约13MPa,在相同的变形条件下,两种实验钢的组织形貌及晶粒尺寸差别较大。两种超低碳BH钢在不同冷却条件下的室温金相组织均是多边形的铁素体,Ti+Nb超低碳BH钢铁素体晶粒较为细小,形状不规则,平均晶粒尺寸为16μm,Ti+V超低碳BH钢铁素体晶粒则较为粗大,形状规则,平均晶粒尺寸为26μm。     

Passivation effects on reactive-ion-etch-formed n-on-p junctions in HgCdTe

The formation of n-on-p junctions by reactive ion etching (RIE) of HgCdTe using an H₂/CH₄ plasma has previously been demonstrated to produce high-performance photodiodes. To fully exploit the inherent advantages of this process, a compatible surface-passivation technology that provides long-term stability is required. This paper examines the effects of thermally evaporated CdTe- and ZnS-passivation on RIE-formed photodiodes undergoing low-temperature baking in a vacuum at temperatures typically used for Dewar bakeout. Experimental results show that as a single passivation layer, neither CdTe nor ZnS are suitable for vacuum packaging of RIE-formed diodes that are to be operated at cryogenic temperatures. A double passivation layer, however, consisting of CdTe passivation and an insulating overlayer of ZnS, produces photodiodes that are stable throughout 175 h, approximately 1 week, of 80°C baking in a vacuum.     

Fatigue strength of high strength dual-phase steel sheet

Fatigue tests have been carried out on lean-alloyed dual-phase steels with tensile strengths ranging from 300–800 MPa. Smooth specimens and specimens with punched holes were tested. The fatigue strength of dual-phase steel was found to be similar to that of other types of steel (eg solution hardened or microalloyed steels) of equal tensile strength. The fatigue strength increases with increasing yield strength. For notched specimens it is also related to the yield ratio. Work and bake hardening increase the fatigue strength of smooth specimens in proportion to the increase in yield strength. For notched specimens this effect is less and is dependent on the yield ratio. Bake hardening of material which was not work hardened also increased the fatigue strength. The notch sensitivity of low yield ratio dual-phase steel is found to be low. The notch sensitivity seems to increase with increasing yield ratio.     

多维麦胚花生芝麻酱的研制

介绍了多维麦胚花生芝麻酱的生产工艺,并通过实验确定出最佳配方和操作要点。结果表明：小麦胚芽、花生仁和芝麻按９∶７０∶２０的比例配比,并添加适量的调味料、稳定剂和抗氧化剂等辅料,能够得到风味、色泽、质地和口感均极佳的产品。