Surface sensitization of the SiCp/Al composite with a high SiC volume fraction

Nickel electroless-plating is a key process for surface metallization of high volume SiC p/ Al composite.Excessive corrosion of the Al alloy of the composite likely occurs in the surface sensitization process before the electroless plating process.It leads to the formation of corrosion holes and the increase of surface roughness of the metalized composite,afterwards,has a negative effect on the soldering process of the composite samples.Surface sensitization of the high volume SiC p/ Al composite was carried out in a Sn Cl2+ HClsensitizing solution in this work,and effects of the sensitizing solution concentration and the sensitizing time on the surface quality of the composite samples were also investigated.The results show that after sensitizing for 0.5 min,Al alloy on the surface of the composite samples is slightly etched,however,the amount of the Sn(OH)2precipitates is much small.After sensitizing for 1.5 min and longer,the amount of the Sn(OH)2 precipitates on the surface of the composite samples increases significantly,but the Al alloy has been etched completely to leave behind some big and deep corrosion holes there.The surface quality cannot be apparently improved through reducing the sensitizing solution concentration.After sensitizing for 1.0 min,the Al alloy is still distributed continuously on the surface of the composites samples,no big or deep corrosion holes are formed,and the amount of the Sn(OH)2precipitates is also appropriate.The surface quality of the electroless plating coating on the high volume SiC p/ Al composite is very well after sensitized for 1.0 min.