Pretreatment effect on the synthesis of Ag-coated Al2O3 powders by electroless deposition process

Ag-coated α-Al2O3 powders were synthesized using silver electroless deposition process, which was carried out in an ammonia-based coating solution containing silver nitrate as a starting material. In the case of using pretreated α-Al2O3 powders, a thin layer of Ag was coated on the α-Al2O3 powders providing a core-shell structure. The thin layer of Ag in thickness had an amorphous structure of about 5 nm. Some crystalline Ag particles about 10 nm in diameter were also observed. However, in the case of using α-Al2O3 powders that were not pretreated, large Ag particles about 100 nm were formed, although a core-shell structure was found on the surface of α-Al2O3 powders.