深小孔脉冲电解加工精度控制研究

为了实现电解加工深小孔的精度控制,建立线性去除率动态数学模型,分析影响动态方程的工艺参数,通过在镍基合金上进行电解加工深小孔试验,分析了脉冲宽度、工具电极进给速度、工具电极绝缘层有无裸露对深小孔加工精度的影响。结果表明：采用较大的脉冲宽度、较大的工具电极进给速度、绝缘层覆盖全部工具电极,有利于提高孔的加工精度。     

HDI板RCC料层孔壁爆裂原因分析和改善

分析了HDI板生产中RCC料层出现孔壁爆裂的原因,同时给出了改善方法,并对此原因和改善方法进行了验证。     

Effect of Electromigration on the Mechanical Performance of Sn-3.5Ag Solder Joints with Ni and Ni-P Metallizations

The effect of moderate electric current density (1 × 10³ to 3 × 10³ A/cm²) on the mechanical properties of Ni-P/Sn-3.5Ag/Ni-P and Ni/Sn-3.5Ag/Ni solder joints was investigated using a microtensile test. Thermal aging was carried out at 160°C for 100 h while the current was passed. The interfacial microstructure and intermetallic compound (IMC) growth were analyzed. It was found that, at these levels of current density, there were no observable voids or hillocks. Samples aged at 160°C without current stressing failed mostly inside the bulk solder with significant prior plastic deformation. The passage of current was found to cause brittle failure of the solder joints and this tendency for brittle failure increased with increasing current density. Fractographic analysis showed that, in most of the electrically stressed samples, fracture occurred at the interface region between the solder and the joining metals. The critical current density that caused brittle fracture was about 2 × 10³ A/cm². Once brittle fracture occurred, the tensile toughness, defined as the energy per unit fractured area, was usually lower than ~5 kJ/m², compared with the case of ductile fracture where this value was typically greater than ~9 kJ/m². When comparing the two types of joint, the brittle failure was found to be more severe with the Ni than with the Ni-P joint. This work also found that the passage of electric current affects the IMC growth rate more significantly in the Ni than in the Ni-P joint. In the case of the Ni joint, the Ni₃Sn₄ IMC at the anode side was appreciably thicker than that formed at the cathode side. However, in the case of electroless Ni-P metallization, this difference was much smaller.     

Plastic constraint of large aspect ratio solder joints

The aspect ratio (joint area/joint thickness) of thin (0.001-0.006 in.) surface mount solder (60S-40Pb) joints plays an important role in determining the mechanical properties and fracture behavior of the joints. This study demon-strates that plastic constraint of a large aspect ratio 60Sn-40Pb solder joint can develop triaxial (hydrostatic) stresses several times greater than the average tensile strength of the bulk solder material. A four to sixfold increase in average joint stress and up to a tenfold increase in peak stress was measured on joints with aspect ratios ranging from 400 to 1000. Although a direct relationship of the aspect ratio to the average tensile stress is shown, as the Friction Hill model predicts, the observed stress increase is not nearly as high but proportional to the classical prediction. This is attributed to the existence of internal defects (oxide particles and micro-voids) and transverse grain boundaries which fail producing internal free surfaces. Thus, the actual aspect ratio is thickness/d², where d equals the distance between internal surfaces. The fracture of these constrained joints was brittle, with the separation occurring between a tin-rich copper tin intermetallic at the interface and the solder matrix. Voids within the solder joint are shown to relieve the plastic constraint and lower the average tensile stress of the joint. The Friction Hill model may play an important role in explaining the small percentage of atypical solder joint failures which sometimes occur on electronic assemblies. In particular, the sudden failure of a thin joint in a strain controlled environment may be attributed to the development of a large hydrostatic stress component. Therefore, a flaw free, plastically constrained joint which develops a high stress state will be a high risk candidate for failure.     

用于激光内雕中的特殊构型谐振腔研究

要实现激光内雕,激光束必须具有数个纳秒量级窄脉宽、数十兆瓦高峰值功率,同时也要具有发散度恒定不变、大深径比的环状聚焦光束。因此,研究和设计了具有特殊构型谐振腔的电光调QNd：YAG激光器。特殊构型腔的关键部件是特殊输出耦合器,其中,镀全反膜层玻璃片的小孔孔径是关键参量。特殊输出耦合器保证了光子在腔内（小孔端口到全反镜之间的距离）往返一周必定逸出腔外,从而使输出光脉冲的宽度为确切的极小数值。     

海工钢管桩被覆聚乙烯粘接剂的试验研究

采用正交设计法研究聚乙烯／钢的热熔粘接剂，得到了择优配方。同时，还测试了环境温度、材质的表面处理等对其粘接强度的影响，以及耐腐蚀性能，另外，还将择优配方粘接剂与部分市售热熔粘接剂进行了性能比较。     

IC封装基板的新一代过孔互连技术

文章主要介绍封装基板芯板通孔的电镀填孔技术及其特点。     

利用镀液组成改善镀层厚度均匀性

概述了利用CuSO4镀液组成控制PCB的贯通孔镀层均匀性和导通孔填充镀层均匀性。     

一种主机与网络相结合的漏洞扫描工具的设计与实现

计算机安全问题是在信息化过程中急需解决的问题 ,而安全漏洞的发现对保护系统安全有着非常重要的意义。网络管理人员由于种种原因 ,很难及时、全面地测试系统的安全性。因此 ,设计一种能代替他们进行测试的工具就显得十分必要。本文首先对漏洞扫描的原理进行了分析 ,主要介绍了一种主机与网络相结合的安全漏洞扫描的设计及实现。     

复合材料结构用高锁螺栓的动态复合加载失效特性

为研究复合材料结构用高锁螺栓的动态复合加载失效特性,基于高速液压伺服材料实验机设计专用的实验支持装置,提出碰撞式实验加载方法。实现中国商用飞机有限责任公司紧固件工艺标准CFBL1001-6-6/CFNT1003CY6抗剪型高锁螺栓在0.01 m/s、0.10 m/s、1.00 m/s加载速度及纯拉伸、30°拉伸-剪切耦合、45°拉伸-剪切耦合、60°拉伸-剪切耦合、纯剪切状态下的失效测试,并基于实验结果拟合得到高锁螺栓的失效参数。结果表明：提出的测试方法能够有效获取高锁螺栓的动态失效参数;CFBL1001-6-6/CFNT1003CY6高锁螺栓的失效模式和失效载荷受加载方式影响较大,受加载速度影响较小;拟合获得的失效方程可较好地表征高锁螺栓的失效特性。