Surface Characterization of Metallic Particles in Printed Circuit Board Comminution Fines and the Processing Implication

From the background of poor responses of metallic particles in printed circuit board comminution fines to chemical conditioning froth flotation schemes, contrary to expectations based on native metal flotation, surface studies were carried out on samples of these metallic particles in quest for the probable causatives. Auger electron spectroscopy combined with argon beam depth profiling was employed in studying the surface make-up of the metal particles. The composition profiles down to 340 nm surface depth obtained showed that the supposed metallic particles consist of organics, oxides, and various trace alloys different from the bulk material of the particles. The profiles reveal the peculiar surfaces of the particles and the matrix from which the particles were liberated. The study provides insight for better appraisal of the flotation system the sample presents. Implementing chemical conditioning flotation scheme on this sample must carefully consider the peculiar surface make up in contrast to native metal occurrences.

高速印刷电路板间完整通孔的全波特性分析

首先将完整通孔分解成内部结构和外部结构,再将外部结构分解成短路问题和天线问题,内部结构分解成多个单层垂直通孔。分别对各分解部分进行全波分析,并根据各部分连接端口处的电流连续性条件将所有分解结构连接起来,实现对完整通孔的全波特性分析。给出了三种不同通孔结构的散射参数与损耗,并分析了损耗产生的原因。

印制电路板的失效分析

印制电路板(PCB)作为一种支撑和互连电子元器件的载板具有结构和功能的双重特性,其性能好坏会直接影响电子设备的可靠性及其失效行为。本文概要评述了印制电路板的失效本质、缺陷类型、表征方法及典型失效案例的剖析等;所介绍的失效分析技术及方法对其他所有材料均有参考价值和实用意义。

电镀级活性氧化铜粉的制备

以纯铜片为原料,经过碳酸氢铵–氨水溶铜、常压脱氨、焙烧等3个阶段,得到了活性氧化铜粉。用扫描电镜(SEM)、X射线衍射(XRD)、电感耦合等离子体原子发射光谱(ICP-AES)等方法对所得活性氧化铜粉的性能进行了表征。结果表明,采用该方法得到的活性氧化铜粉纯度达到99%以上,金属杂质含量和溶解速率完全符合电镀级氧化铜粉的要求,可以直接用于线路板的电镀铜。