Joint Strength with Soldering of Al2O3 Ceramics After Ni-P Chemical Plating

Ni-P alloy was chemically plated on Al2O3 ceramics to produce uniform alloy coatings at temperatures below 70~C. Cu metal was electroplated onto the Ni-P coating to facilitate the soldering and shorten the chemical plating time. Then, the electroplated ceramic specimens were soldered with 60 wt.% Sn-40 wt.% Pb solder in active colophony. The highest shear strength was acquired after the heat treatment at 170℃ for 15 min. The joint fractures mostly propagated along the interface between the ceramics and the Ni-P coating, with some fracture in both the ceramics and the Ni-P coating near the interface and some along the interface between the Cu and Ni-P coatings. The results show that ceramic surface roughness and the chemical plating parameters influence the coating quality, and that suitable heat treatment before the soldering also improves the adhesion between the ceramics and Ni-P coatings, thus strengthening the joints.     

双复纤维的制备与性能分析

采用化学镀工艺制备双复纤维材料,将该材料均匀分散于有机高分子胶粘剂中,在结构上进行设计,制成一定规格的平板试样,并进行电磁参数和反射率的测量。通过对测量所的数据的分析,可以得出该材料在含量为3%,在增加底层的基础上,d=0.8mm时,最小反射率R=-18.73dB,低于-10dB的有效带宽为10GHz,而且利用该材料制成的涂层面密度比较低,有可能成为良好的轻质高效吸波剂。     

8 mm波段隐身涂层的设计与性能研究

主要在毫米波波段范围内,采用新型材料,分析了各种材料所能达到的性能指标,并对雷达波隐身涂层进行多层结构设计,按照分析结果制备了平板样品,对其吸波性能进行测试,通过对测试结果的分析,采用这种设计方法后,在毫米波段对雷达波具有较好地吸波性能。