Fabrication and interaction mechanism of Ni-encapsulated ZrO2-toughened Al2O3 powders reinforced high manganese steel composites

In order to solve the cast-infiltration difficulty and low interface bonding strength of ZrO2-toughened Al2O3 (ZTA) powders reinforced high manganese steel (HMS) matrix composite, uniform and continuous Ni-encapsulated ZTA powders (ZTA(p)@Ni) as reinforced phase are fabricated by electroless deposition assisted with ionic liquid additive. The effects of Ethaline concentration, temperature, ZTA concentration and deposition times on the morphology of ZTA(p)@Ni have been investigated. Experimental results show that the thickness of Ni coating is about 7-10 mu m, and there is no casting crack or shrink on the composite, so compact bonding between ceramic and matrix is obtained. In addition, the impact abrasive wear resistance testing demonstrates that the performance of ZTA(p)@Ni reinforced HMS composite is superior to that of matrix. On the basis of experimental analysis, a schematic illustration of the cast-infiltration process is put forward. It implies that Ni-encapsulated ZTA can be wetted with molten HMS matrix to form a ZTA/Al2NiO4-Al2MnO4/Fe interface layer through Ni diffusion and reactive wetting. The interdiffusion of Ni and other elements at ZTA interface layer can reinforce the interfacial bonding strength to form an interface layer between metal and hard phases. (C) 2019 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.