Alumina-based nanocomposites fabricated by a novel soaking method

Nickel dispersed alumina matrix nanocomposites were fabricated using a novel soaking method. Secondary particles were introduced into the nano-pores of a porous matrix grains by a soaking method, such that gamma-alumina powder was soaked in nickel nitrate solution under vacuum. During pre-calcination, nickel oxide particles were created inside of the nano-pores of gamma-alumina. The alumina powders were then reduced under hydrogen atmosphere to obtain nano-sized metallic nickel embedded in gamma-alumina grains. The alumina-nickel composite powders were sintered by pulse electric current sintering (PECS) technique with a-alumina seeds. The maximum strength of the alumina-nickel nanocomposites was 984 MPa after sintering at 1,450 degrees C with cc-alumina seeds, where the specimen size was 2 x 2 x 10 mm(3). The maximum fracture toughness was 5.5 MPa(.)m(1/2) after sintering at 1,350 degrees C with seeds measured by the single edge V-notched beam (SEVNB) method.