WC-Co alloys have enjoyed great practical significance owing to their excellent properties during the past decades. Despite the advantages, however, recently there have been concerns about the challenges associated with the use of Co, i.e. price instability, toxicity and properties degeneration, which necessitates the fabrication of binderless tungsten carbide (BTC). On the other hand, BTC or BTC composites, none of them, to date has been commercialized and produced on an industrial scale, but only used to a limited extent for specialized applications, such as mechanical seals undergoing high burthen as well as high temperature electrical contacts. There are two challenges in developing BTC: fully densifying the sintered body together with achieving a high toughness. Thus, this review applies towards comprehensively summarize the current knowledge of sintering behavior, microstructure, and mechanical properties of BTC, highlighting the densification improving strategies as well as toughening methods, so as to provide reference for those who would like to enhance the performance of BTC with better reliability advancing them to further wide applications and prepare the material in a way that is environment friendly, harmless to human health and low in production cost. This paper shows that the fabrication of highly dense and high-performance BTC is economically and technically feasible. The properties of BTC can be tailored by judiciously selecting the chemical composition coupled with taking into careful account the effects of processing techniques and parameters.

WC–Co alloys have enjoyed great practical significance owing to their excellent properties during the past decades. Despite the advantages, however, recently there have been concerns about the challenges associated with the use of Co, i.e. price instability (the major incentive for alternative binder development), toxicity and properties degeneration. Thus, the current study applies towards summarize the current knowledge of the impacts of different binders partial or total substitution of the traditional cobalt binder highlighting the influences of metal, intermetallic compound, ceramics (metal oxide) binders on the sintering behavior as well as mechanical properties of WC-based alloys, so as to provide reference for those who would like to enhance the performance of cemented carbides with better reliability advancing them to further wide applications and prepare the alloys in a way that is environment friendly, harmless to human health and low in production cost. It is concluded that the alternative for cobalt in tungsten carbide cemented carbide is economically and technically feasible. Strict control of the chemical composition of the binder coupled with taking into careful account the effects of sintering process and subsequent treatments is of great importance to improve the sintering behavior and tailor mechanical properties of tungsten carbide-based hardmetals.

There has been growing interest in the high-entropy ceramic (HEC) recently owing to its tailorable compositions and microstructures, versatile properties, together with promising structural and functional applications. However, inferior fracture toughness (K_IC) and damage tolerance restricted many practical applications of the HEC. Herein, we addressed this challenge by incorporating a three-dimensional graphene–carbon nanotube (3D G–CNT) as toughening agent in (Hf_0.2Nb_0.2Ta_0.2Ti_0.2Zr_0.2)C. The resulting enhanced 3D G–CNT/(Hf_0.2Nb_0.2Ta_0.2Ti_0.2Zr_0.2)C featured an outstanding toughness of 8.23 MPa·m^1/2, while remaining superior strength (763 MPa) and hardness (24.7 GPa). An ultralow friction coefficient (0.15) coupled with an ultralow wear rate (w, 2.6×10⁻⁷ mm³/(N·m)) in the 3D G–CNT/(Hf_0.2Nb_0.2Ta_0.2Ti_0.2Zr_0.2)C was obtained primarily as a function of lubricating scrolls, in which two-dimensional (2D) graphene acted as a tribolayer, and one-dimensional (1D) carbon nanotubes acted as nano ball bearings embedded inside. Strikingly, the 3D G–CNT/(Hf_0.2Nb_0.2Ta_0.2Ti_0.2Zr_0.2)C exhibited rather low thermal conductivity (κ) yet excellent electrical conductivity (σ, 1.3×10⁶ S/m) in comparison with the pure (Hf_0.2Nb_0.2Ta_0.2Ti_0.2Zr_0.2)C. This study provided great potential for maximizing the physical and functional properties of the HEC for various applications.