Industrial Deposition of W-B-C Coatings: Properties and Process Modelling
| Authors | |
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| Year of publication | 2022 |
| Type | Conference abstract |
| MU Faculty or unit | |
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| Description | W-B-C coatings have the potential to replace current state-of-the-art hard protective coatings in the industry owing to their unprecedented combination of high hardness and increased fracture resistance, as the brittle fracture is the most limiting shortcoming of the traditional hard protective coatings based on ceramics such as TiN, CrN, AlN, and their combinations. So far, only a few studies have dealt with industrial deposition of the W-B-C coatings. This study shows the properties of W-B-C coatings industrially deposited by non-reactive magnetron sputtering using a system provided by SHM, Czech Republic. The system utilizes a single cylindrical sputter source fitted with a segmented target composed of tungsten, boron carbide, and graphite segments. The segmented target provides for the adaptation of the coatings' chemical composition by rearranging the position of individual segments. As an industrial standard, the planetary table capable of multi-axis rotation of substrates was used to simulate batch coating of the tools. The depositions were carried out in both stationary and single-axis rotation regimes to understand the differences between laboratory-like and industrial preparation of the coatings. W-B-C coatings were studied over a broad range of chemical compositions. Although the coatings were mostly amorphous, they still exhibited high hardness (up to 29 GPa) and elastic modulus (up to 440 GPa). Detailed analyses of their mechanical properties proved their superior fracture resistance compared to current ceramic-based protective coatings. The comparison of the fracture resistance was possible using the instrumental indentation technique and indentation tip with a very small curvature radius (cube-corner diamond tip) and very thick coatings. This method induced cracking in the coating without the significant influence of the substrate. To further ease the industrial utilization of these coatings, a simple yet powerful model was developed to predict the influence of the target setup and the influence of movement and placement of the substrates in the chamber. The modelling procedure was based on freeware SDTrimSP for the sputtering processes and SiMTra for the particle transport. The results showed very good agreement in terms of chemical composition as well as the relative thickness of the coatings. They were able to identify the crucial difference between the laboratory-like and industrial preparation of the W-B-C coatings. |
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