Pilot deposition experiments of X2BC system in Japan

Assoc. Prof. Pavel Souček and Dr. Peter Klein traveled to Tokyo Metropolitan University, Japan. They planned pilot experiments on the research of X2BC-based thin films. Assoc. Prof. Tetsuhide Shimizu invited them to Japan as their colleague. They worked in his Tokyo lab at the end of July 2023.

Japanese colleagues specialize in HiPIMS thin film deposition technology and its evaluation. More specifically, they are working on the development of hard and yet flexible protective coatings. Dr. Klein comments on their research, "Nowadays, the industry demands new types of materials that have good hardness but also toughness and flexibility. Companies are no longer interested in coatings just for machining that can withstand mechanical stress. The Nb2BC system could become one such material."

In the past, Tetsuhide Shimizu has worked with various European groups, e.g., Ulf Helmersson's group in Linköping, Sweden. From multiple scientific meetings, he is familiar with our scientists from Prof. Vašina's research group, Deposition of Thin Films and Nanostructures, at the Department of Physics and Technology. Tetsuhide Shimizu focused on magnetron sputtering later in his scientific career as a materials engineer, and he and the scientists at the DPPT are now working together on the deposition of thin films based on the Nb2BC system and the diagnosis of the deposition process.

The Japan trip aimed to exchange experiences and know-how in depositions and diagnostic measurements using QCM equipment. Dr. Klein is an expert in HiPIMS discharges and their diagnostics using the device mentioned above, which can measure the flux of ions and atoms incident on the growing layer. The scientists brought this equipment with them to Japan. "We also brought a specially modified magnetron head with an anode designed for diagnostics. We were able to install it in one of the three deposition chambers our Japanese colleagues have at their disposal in the laboratory," comments Assoc. Prof. Souček, an expert in preparing hard yet tough coatings in X2BC systems.

"With QCM, we can directly determine the flux of the particles forming the deposited coating. We can also distinguish whether they are atoms or ions. This is absolutely crucial for the formation and composition of the coating, which ultimately determines the final overall mechanical properties of the thin film. QCM equipment has many advantages over the most commonly used optical diagnostics, especially in diagnosing X2BC processes, as we do not see any boron or carbon emission lines in the optical spectra," adds Dr. Klein.

The QCM device is on loan for follow-up experiments in September 2023. Thanks to the new collaboration, the scientists plan to write a joint publication and conduct further collaborative research in the future as part of the planned project.