Herein, the effect of adding VC with different contents and Mo₂C, WC and TaC on the core-rim structure evolution of TiC-based cermets was investigated using x-ray diffraction, scanning electron microscopy and energy-dispersive spectroscopy. Results show that the added secondary carbides exhibiting the same crystal stucture as TiC are prone to solid dissolution in TiC grains and change the core-rim stuctures of TiC-based cermets. With the addition of only VC, (Ti,V)C is the main component in the black core-grey rim structure and increasing the VC content is beneficial for promoting the dissolution process of cores. With the addition of multiple carbides, the core-rim structure in cermet Ta-7 is effectively improved, showing a high percentage of white core-grey rim structures, and the mechanical properties are improved.

Fe-Cr-Nb-C wear-resistant alloy coatings were successfully fabricated on high-carbon forged steel via coaxial powder feeding laser cladding. The evolution of microstructure and wear resistance with varying Nb content was systematically investigated. The results indicate that appropriate NbC addition markedly modifies the distribution of grain and boundary carbides. As Nb content increases from 2.5 wt% to 3.5 wt%, nanoscale rod-like NbC precipitates form uniformly along boundaries, effectively suppressing the formation of brittle Cr₂₃C₆ precipitation. Semi-coherent NbC/matrix interfaces and NbC-induced grain refinement reduce adhesive/abrasive wear, thereby improving hardness and wear resistance. At 4.5 wt% Nb, discrete micron-sized NbC particles form within the grains, yielding optimal performance. However, excessive Nb (≥5.5 wt%) causes NbC agglomeration, inducing stress concentrations and large spallation pits that deteriorate wear resistance. This work highlights NbC morphology as a key factor for tailoring coating properties.

VC is important carbide additive and has a similar crystal structure with TiC. In this study, the effect of adding VC amounts at content levels of 1–8 wt% on the microstructure evolution and mechanical properties of TiC-based cermets is examined. The specimens were characterized by scanning electron microscopy observations, energy-dispersive x-ray spectroscopy analysis, Image-Pro plus statistical analysis, transverse rupture strength tests, and hardness tests. The results show that VC addition is beneficial to promote the liquid-phase sintering process. When the VC addition amount is lower than 4 wt%, added VC mainly distributes in the surrounding outer rims. With increasing VC additive, the black cores are slowly dissolved and the average thickness of rims increases slightly. Many dimples exist in the fracture morphology and the strength increases gradually. Furthermore, when the VC content increased to 6–8 wt%, a part of VC is solid-dissolved with TiC, black cores with large grain appear and surround with thick outer rims. The large core-rim structure exhibits transgranular fracture mode and causes the toughness decreased.

The influence of Cr3C2 addition on the microstructure and mechanical properties of TiWMoC-based cermets was investigated by using SEM, EDS, XRD, TRS, and Hardness tests. Results show that Cr3C2 mainly dissolved in binder phase and the dissolution of Cr3C2 into the binder phase reduced the solubility of TiC, WC, and Mo2C. When less than 1.2 wt% Cr3C2 was added, more dimples appeared in the fracture surface. Crack deflection and reduced porosity improved mechanical properties of TiWMoC-based cermet. When Cr3C2 was increased to 1.6 wt%, the crack propagation path became transgranular fracture-led model, the porosity increased and the mechanical properties decreased. When 1.2 wt% of Cr3C2 was added, the comprehensive mechanical properties were optimal.