TPU Researchers Proposed A New Method To Synthesize High-Temperature Ceramic Coatings In One Step

Researchers of Tomsk Polytechnic University, as part of a scientific collaboration, have for the first time obtained multicomponent carbides and carbonitrides in the form of coatings on metals using plasmodynamic synthesis in one step. Unlike its analogues, the method of the TPU researchers allows to stably obtain a material with a given structure of high strength and hardness, capable of withstanding high temperatures.

The research was supported by a grant from the Russian Ministry of Education and Science (project no. FSWW-2025-0003). The results have been published in the International Journal of Refractory Metals and Hard Materials (Q1, IF: 4.6).

High-entropy carbides are compounds of four or more metal elements. They are extremely durable and have thermal resistance, which is important for aerospace engineering and other devices operating under extreme conditions. Such materials are usually produced in several stages: grinding of the feedstock and its sintering with silicon carbide. This complicates the process of synthesis and doesn't provide for a pure product as a result. Moreover, finished products have a wide range of final characteristics due to impurities.

TPU researchers, as part of a scientific group, have developed a new method for single-stage production of high-entropy carbides. It is based on jet dispersion of arc plasma at high speed. To obtain a material by this method, the raw material is placed in the plasma formation channel. Then, under the influence of high temperature, velocity and pressure, the plasma is deposited on a copper plate, forming a uniform coating. The entire synthesis process takes place in a gaseous environment.

We tested our method on the production of multicomponent carbide and carbinitride of titanium, zirconium, niobium, hafnium and tantalum. Their synthesis took place in argon and nitrogen environments. The thickness of the finished material, which forms a cubic crystalline phase without impurities, reaches up to 20 microns. This is the first time such results have been obtained. The fact is that the existing approaches to the synthesis of high-entropy carbides and carbinitrides did not allow us to obtain unambiguous results due to the complexity of the formation of multicomponent compounds and a wide range of the properties of finished products. Our method allows us to spray high-entropy ceramic coatings with a stable cubic structure, which makes it possible to conduct their comprehensive studies, - notes Dmitry Nikitin, one of the authors of the study, associate professor of the Department of Electric Power and Electrical Engineering at TPU.

The TPU researchers studied the composition by X-ray diffractometry, as well as the mechanical properties and thermal stability of the finished products. The results showed that the hardness of high-entropy coatings is 32-35 GPa, which exceeds the predicted values for similar material compositions and the characteristics of the corresponding simple carbides. According to the researchers, the samples obtained by the new method also have high oxidation resistance: the coatings retain their crystalline structure at a temperature of 700 °C, which makes them promising for use in aggressive environments.

Our proposed method is universal, and it can be used to synthesize many new multicomponent carbides with a specific composition, structure, and properties in the future. This will make it possible to develop the design of ceramic coatings for specific practical tasks, for example, to counteract the wear of metal products at extreme temperatures or to increase their corrosion resistance, — adds Dmitry Nikitin.

The study involved researchers from the Laboratory of Advanced Materials for the Energy Industry of Tomsk Polytechnic University, the Skolkovo Institute of Science and Technology and the Pirogov Russian National Research Medical University.