Structural and Mechanical Properties of a-BCN Films Prepared by an Arc-Sputtering Hybrid Process

Yuki Hirata,Yoshinao Iwamoto,Mikito Yoshizato,Masao Kawagoe,Naoto Ohtake,Ryotaro Takeuchi,Hiroyuki Taniguchi,Hiroki Akasaka

doi:10.3390/ma14040719

Yuki Hirata, Yoshinao Iwamoto + Show 6 more

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https://doi.org/10.3390/ma14040719

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Journal: Materials	Publication Date: Feb 3, 2021
Citations: 7	License type: CC BY 4.0

Affiliation: Tokyo Institute of Technology

Abstract

Amorphous boron carbon nitride (a-BCN) films exhibit excellent properties such as high hardness and high wear resistance. However, the correlation between the film structure and its mechanical properties is not fully understood. In this study, a-BCN films were prepared by an arc-sputtering hybrid process under various coating conditions, and the correlations between the film’s structure and mechanical properties were clarified. Glow discharge optical emission spectroscopy, X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, and Raman spectroscopy were used to analyze the structural properties and chemical composition. Nanoindentation and ball-on-disc tests were performed to evaluate the hardness and to estimate the friction coefficient and wear volume, respectively. The results indicated that the mechanical properties strongly depend on the carbon content in the film; it decreases significantly when the carbon content is <90%. On the other hand, by controlling the contents of boron and nitrogen to a very small amount (up to 2.5 at.%), it is possible to synthesize a film that has nearly the same hardness and friction coefficient as those of an amorphous carbon (a-C) film and better wear resistance than the a-C film.

Highlights

Energy-saving and environment-friendly technologies have gained increasing attention in recent years from the viewpoint of preventing global warming and the depletion of energy resources
The heat resistance of Diamond-like carbon (DLC) film depends on its structure; it has been reported that the heat resistance of hydrogenated amorphous carbon film (a-C:H) is ~300–350 ◦C [5,6], and that of tetrahedral amorphous carbon film is ~400–600 ◦C [7]
Conclusions amorphous boron carbon nitride (a-BCN) thin films were successfully prepared with carbon contents in the range of 40–100% using a newly developed film coating setup, which combines vacuum arc vapor deposition and magnetron sputtering

Summary

Introduction

Energy-saving and environment-friendly technologies have gained increasing attention in recent years from the viewpoint of preventing global warming and the depletion of energy resources. Hard coating technology has attracted significant attention because such functional thin films have excellent mechanical properties, such as high hardness, low coefficient of friction, and high wear resistance. In many cases, these hard films are composed of light elements like carbon, nitrogen, and boron, and they are widely applied to moving parts to reduce friction loss and extend the service life of machine tools [2,3]. The heat resistance of DLC film depends on its structure; it has been reported that the heat resistance of hydrogenated amorphous carbon film (a-C:H) is ~300–350 ◦C [5,6], and that of tetrahedral amorphous carbon film (ta-C) is ~400–600 ◦C [7]. DLC films cause diffusion wear against iron-based metals, and, they cannot be coated on cutting tools for processing steel materials

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