The discovery of tribochemical reactions at the sliding interfaces has suggested new pathways for material synthesis. This study explored the formation of thin functional films at the steel-on-silicon sliding interfaces, with toluene as base liquid and five different additives i.e. Zinc dialkyldithiophosphates (ZDDP), 3-Aminopropyltriethoxysilane (APTES), Octadecyltrimethoxysilane (OTMS), (3-mercaptopropyl) trimethoxysilane (MPTMS) and Octadecene. All additives were found to result in thin functional films of varying chemical, mechanical, and electrical characteristics. The Octadecene and OTMS APTES produced carbon rich tribofilms. The OTMS tribofilms were soft, as revealed by the quantitative nanomechanical analysis. The MPTMS and ZDDP additives resulted in conductive thin films in a well-defined linear pattern. The MPTMS resulted in continuous conductive films with surface coverage higher than that of the ZDDP.

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The reaction pathways of Cu oxidation by the chemical mechanical polishing (CMP) slurry containing ceria (CeO₂) abrasive grains were theoretically investigated. First-principles molecular dynamics (FPMD) simulations were employed to analyze the reaction pathways between a CeO₂ surface and a Cu surface. As a result, the following reactions were observed: chemical bonds between CeO₂ and Cu were formed, electron transfer from Cu atoms to Ce atoms occurred, a water molecule dissociated on the CeO₂ surface to form a proton and an OH⁻ ion, and the generated OH⁻ ion formed Cu-O bonds with the oxidized Cu atoms. The candidate reaction pathways for Cu oxidation, including those observed in FPMD simulations, were further analyzed by constructing energy diagrams using density functional theory (DFT) calculations. As a result, the reaction pathway observed in the FPMD simulation was identified as the most likely candidate, having the lowest activation energy and the lowest final structure energy. These results indicate that the oxidation reaction pathways of Cu in the slurry containing CeO₂ abrasive grains involve electron transfer through the formation of chemical bonds between CeO₂ and Cu, as well as the supply of oxygen atoms derived from water to Cu atoms.

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The high-power impulse magnetron sputtering (HiPIMS) is a deposition method that has potential to achieve both high hardness and high surface smoothness of diamond-like carbon (DLC) films, and investigation has been performed to optimize the deposition process. However, the dominant HiPIMS process factors that affect the hardness and wear properties of DLC films have not been clarified based on the observation of plasma properties. In this study, we focused on the sputtering gas species that affect the densities of carbon ions in the plasma and the target magnetic field strength, which affects the ion transportation and its incident flux onto the deposition substrate. The results of this investigation reveal that the addition of neon to the conventional sputtering gas of argon promoted carbon ionization and the incident carbon ion flux on to the substrate was increased by suppressing the back attraction of carbon ions to the target in a weak magnetic field strength. It was also confirmed that these effects could potentially improve the hardness and wear properties of DLC films.

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