Microstructure, cracking susceptibility and abrasive wear resistance of core-shell ceramic particles reinforced laser cladding coatings

Abstract

In this study, the typical core-shell ceramic particles were synthesized in-situ in the Fe-based composite coating using the laser cladding technology. The core-shell ceramic particles were composed of a pure TiC core and a (Ti,Nb,W)C multiple carbide shell, exhibiting fine cubic morphologies with particle sizes ranging from 0.5 μm to 1.0 μm rather than coarse dendritic morphologies. These core-shell ceramic particles were uniformly distributed in the entire coating with no obvious gradient distribution from the upper to the bottom. With the formation of the core-shell ceramic particles, the clad coating showed a more stable microhardness distribution along the depth direction and a lower cracking susceptibility than the original coating, and its average microhardness value (about 410 HV0.5) was only about 64 % of that of the original coating (about 640 HV0.5). Besides, the introduction of the core-shell ceramic particles caused the clad coating to possess the excellent abrasive wear resistance, which was approximately 10 times higher than that of the original coating. This significant improvement was attributed to the outstanding dispersion strengthening effect provided by the core-shell ceramic particles.