Wettability and interaction mechanism for Ni-modified ZTA particles reinforced iron matrix composites

The wetting behaviors of bare and Ni-modified zirconia toughened alumina (ZTA) with molten iron matrix have been explored by sessile drop technique and gathered to compare their wettability. Experimental results show that the wetting angles of molten 65Mn steel and high chromium cast iron (HCCI) matrix on bare ZTA substrates are 104.1 degrees and 102.3 degrees, respectively, whereas it is decreased to 83.6 degrees and 88.2 degrees on Ni-modified ZTA substrates. The wetting angle of HCCI matrix on Ni plate is just 1.5 degrees in 1 min. At high casting temperature, element Ni originated from Ni coating can diffuse into molten Fe and keep constant basically. Small amount of element Ni can react with Al2O3 on ZTA/Fe interface to form Al2NiO4. A schematic illustration of the cast-infiltration process is put forward, which indicates that Ni-modified ZTA can be wetted with molten iron through Ni diffusion and reactive wetting. A ZTA/Al2NiO4/Fe interface layer is formed by mechanical bonding, interdiffusion and small amount of chemical reactions, to achieve composites with tight interfacial bonding strength. Besides, Ni-modified ZTA particles are prepared through electroless plating assisted with Ethaline additive and used as precursor to reinforce 65Mn steel matrix composite by nonpressure casting infiltration method. (C) 2019 Elsevier B.V. All rights reserved.