Study of Electroless Silver Plating on Hollow Glass Microspheres

Formaldehyde was used as the reducing agent to prepare silver coating on hollow glass microspheres via electroless plating.The effects of various factors including pretreatment,reaction speed,loadage of glass microspheres,pH value of the bath,and the feeding mode of silver ammonia solution on the effectiveness of silver-plating process were investigated,based on morphology and phase composition analyses of the coatings using scanning electron microscopy and X-ray diffraction.As the results,it was imperative to properly control the loadage of the glass microspheres,the dripping rate of the silver ammonia solution,and the reaction temperature so as to rationally reduce the plating rate.It was suggested to slowly feed the silver ammonia solution and mildly decrease the reaction temperature,which could be critical to the formation of uniform and compact silver coating with good bonding strength to the sucstrate and small volume resistance.