First high-pressure and high-temperature investigations on the Ti-C-N and Zr-C-N ternary systems

Transition metal carbides, nitrides, and carbonitrides are an important class of cermets (composite metalceramic solids) widely used in cutting tools, polishing, coatings, and aerospace applications, etc., due to their exceptional hardness, chemical stability, and high melting points. However, many industrial cermets are based on environmentally unfriendly 5d transition metals such as hafnium, tungsten, or rhenium, which are rare, difficult to extract, and hazardous. In contrast, titanium and zirconium—which belong to the same group as Hf in the periodic table—are abundant, less toxic, and more sustainable, yet their potential in 5d transition-metal carbonitrides remain largely unexplored.