Silver-plated aluminum powder preparation technology and performance
|School||Kunming University of Science and Technology|
|Keywords||aluminum powder silver coated aluminum electroless copper plating electroless silver plating|
Silver coated aluminum powder is a kind of functionality conductive filler, which is applied to the fields of conducting resign, electromagnetic shielding materials, absorbing materials, anti-static materials when it was appended in coating, bond, printing ink, plastic, rubber. Because of the characteristics of aluminum powder, the electroless plating of aluminum powder is difficult. In this paper, the silver coated aluminum powder which had good electric property and stable property was produced by twice electroless plating. The aluminum powder whit 40μm in size was firstly coated copper and then the copper coated powder was coated silver.The influence of NaOH* concentration, Cu2+ concentration, NH3·H2O concentration, Cu/Ag ration, Ag+ complexing reagent A concentration, NaOH concentration, loadage, silver content and granularity on the color, compact resistance, apparent density and anti-oxidation property of silver coated aluminum powder and silver plating time were studied by condition experiment. The results as fallows:（1） The color became dark with the increase of NaOH* concentration, Cu2+ concentration and loadage, it became light with the increase of silver content, NH3·H2O concentration, Ag+ complexing reagent A concentration, Cu/Ag ration and granularity, and it firstly became light and then became dark with the increase of NaOH concentration.（2） The compact resistance increased with the increase of Cu2+ concentration and loadage, it decreased with the increase of NaOH* concentration, silver content, Ag+ complexing reagent A concentration and granularity, and it was firstly decreased and then increased with the decrease of Cu/Ag ration, NaOH concentration and NH3·H2O concentration.（3） The apparent density increased with the increase of Ag+ complexing reagent A concentration, loadage, silver content and granularity, it firstly increased and then decreased with the increase of Cu/Ag ration, and it had no relation to other factors, and it was 1.3-1.4g/cm3 usually.（4） The anti-oxidation property of silver coated aluminum powder was steady, the color and compact resistance didn’t change when putted it which was produced in allfactors to air for a month.（5） The silver plating time prolonged with the increase of loadage, silver content and granularity, it was contrary to other factors.The SEM and XRD micrograph indicated that the silver coated aluminum had good dispersibility and the coating is even, dense and pure, which didn’t contain oxide. It showed that the silver coated aluminum was a core-shell structure of Al core, Cu inner layer and Ag outer layer by analyzed further.In a word, low density, low compact resistance, light color, dense coating and dispersed silver coated powder can be gotten by elctroless copper plating and electroless silver plating. This method had many advantages such as, easy operability, low cost, environment friendly and strong practicability, having better application prospect.