Phase formation, thermal stability and mechanical properties of Nb-B-C coatings prepared by combinatorial magnetron sputtering
| Authors | |
|---|---|
| Year of publication | 2022 |
| Type | Article in Periodical |
| Magazine / Source | Surface & Coatings Technology |
| MU Faculty or unit | |
| Citation | |
| Web | https://www.sciencedirect.com/science/article/pii/S0257897222000585 |
| Doi | http://dx.doi.org/10.1016/j.surfcoat.2022.128137 |
| Keywords | Nb-B-C; Coatings; Combinatorial magnetron sputtering; Protective coatings; Thermal stability; Mechanical properties |
| Description | In this study, combinatorial magnetron sputtering was used to deposit Nb-B-C coatings in a wide composition range. The phase formation, thermal stability and mechanical properties of these coatings were investigated in relation to their composition and deposition conditions. The studied coatings were amorphous, short range ordered or exhibited crystalline phases such as Nb, NbC and NbB2. Higher energy flux to the coating achieved by the use of bias and heating during deposition resulted in coatings being crystalline over a wider composition range. Annealing of the coatings after deposition resulted in a higher degree of crystallinity as well as an increase in hardness and effective elastic modulus. The hardness of the coatings was up to 22.5?±?0.7?GPa before and up to 35.0?±?0.6?GPa after annealing. The effective elastic modulus was up to 240?±?10?GPa before and up to 310?±?7?GPa after annealing. Coatings with a high B content exhibited the highest hardness and elastic modulus in both cases. Coating powder was prepared by sputtering a Nb2BC target and studied using differential scanning calorimetry. The powder exhibited a crystalline NbC phase before and after annealing up to 900?°C. The material was stable in an Ar atmosphere in the studied temperature range. In an Ar?+?O2 mixture, the powder was stable up to ~580?°C. At this temperature, an oxidation reaction started, resulting in the formation of Nb2O5. |
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