Resumen
TiC/Ni composite coatings on H13 steel plates were fabricated in situ by self-propagating high-temperature synthesis and combined with a pseudo-heat isostatic press. The microstructure of the coating was characterized by X-ray diffraction and scanning electron microscopy. The microhardness, corrosion, and thermal fatigue behaviors of the coating were investigated by a microhardness test, immersion test, and thermal fatigue test, respectively. The results showed that the in situ coating consisted of TiC and Ni binder phases. Spheroidal TiC particles were enveloped by a nearly continuous Ni binder phase. Coating showed good metallurgical bonding in the interface. The corrosive mechanism of the coating surface in molten aluminum alloy involves the Ni binder phase being etched by aluminum to form AlNi3 and the oxidization of the TiC-reinforced phase. The corrosive mechanism that occurred at the front of the corrosion involves the Ni binder phase of the coating being etched by aluminum to form AlNi3, while the TiC skeleton still maintains the original organizational structure. Hot fatigue cracks began at the defective tips of the coating and propagated in the TiC-reinforced phase. The crack is a trans-granular fracture, which is the result of brittle rupture.