In this work, a comparative study of the tribological performance of two hard coatings, CrN/TiBN, was conducted for research purposes and industrial applications in food products, particularly for food packaging into cans using the double hermetic sealing process. CrN and TiBN coatings were successfully deposited on a base-cobalt metal substrate of a CoCrW commercial alloy using physical vapor deposition by arc evaporation (AEPVD) technology to improve the tribological properties of the commercial alloy, including wear and corrosion resistance, lower coefficient of friction, and overall durability. This research focuses on conducting scratch and abrasion wear resistance tests in dry conditions; specifically, it pursues to evaluate the wear corrosion properties, known as tribocorrosion performance, on CrN/TiBN hard coatings. The experimental results show that the CrN coating (2.9 μm) is slightly thicker than the TiBN coating (2.7 μm), with a 47 N critical load. It also shows a lower coefficient of friction (CoF) in a dry environment, while the TiBN coating showed total detachment and a high coefficient of friction in a dry environment condition. Tribocorrosion testing in brine aqueous solution indicated that CrN coating shows a high friction coefficient with a higher open circuit potential value (E_corr), and TiBN shows the lowest corrosion potential (E_corr) and the lowest friction coefficient. This suggests that CrN could provide better corrosion protection for commercial cobalt alloys and improve tool performance during the food canning process in brine environments.

In this study, novel findings were obtained regarding the influence of a 10 A current intensity on the growth of an FeB–Fe2B layer during pulsed-DC powder-pack boriding. Boride layer formation was carried out on AISI 316 L steel at 1123–1223 K for different exposure times at each temperature, considering 10 s polarity inversion cycles. The boride layer was characterized by x-ray diffraction and high-speed Berkovich nanoindentation, the latter being used to determine the hardness and reduced Young’s modulus mappings along the depth of the layer-substrate system. Moreover, the growth kinetics of the FeB–Fe2B layer on the steel’s surface was modeled using the heat balance integral method (HBIM). This involved transforming Fick’s second law into ordinary differential equations over time, assuming a quadratic boron concentration profile in space to determine the B diffusion coefficients in FeB and Fe2B, respectively. From the Arrhenius relationship, the B activation energies in the boride layer were estimated considering the contribution of the electromigration effect; the results showed an approximately 30% reduction compared to the values obtained in the conventional powder-pack boriding for AISI 316 L steel. Finally, the theoretical layer thickness obtained by the HBIM demonstrated an error of no more than 5% against the experimental FeB and FeB + Fe2B layer thickness values.

Cobalt-based alloys, such as cobalt-chromium-molybdenum (CoCrMo), are known for their high mechanical strength and find extensive applications in the biomedical field such as manufacturing of tools, dental components, and orthopedic implants. The longevity of the CoCrMo alloy in service is intricately linked to its resistance to corrosion and wear. Specifically, tribocorrosion can contribute to material loosening; therefore, it is essential to explore surface treatments for cobalt-based alloys as a means to enhance their wear resistance, ensuring the prolonged durability of the material. This study provides novel insights into the bio-tribocorrosion resistance of the borided CoCrMo alloy when immersed in calf serum, emulating the synovial fluid. Two distinct microstructures of boride layers were examined in this research: (1) a CoB–Co2B layer formed through powder-pack boriding and (2) the borided surface underwent diffusion annealing to completely dissolve the CoB, resulting in a monophasic layer (Co2B). Following the ASTM G119-09 procedure, the total material loss (T), encompassing both material loss due to wear (WC) and corrosion (CW), was determined using a linear reciprocating ball-on-flat tribometer equipped with an electrochemical cell. Test results indicated that the presence of CoB–Co2B and Co2B layers on the CoCrMo alloy increased bio-tribocorrosion resistance approximately 2.4 times and 1.3 times, respectively, compared to the non-treated CoCrMo alloy. A dominant wear regime was observed for the borided surface exposed to diffusion annealing and the non-treated CoCrMo alloy, whereas the borided CoCrMo alloy exhibited a corrosion-wear regime. Clearly, these findings highlight the capability of the cobalt boride layer to improve the performance and extend the service life of the CoCrMo alloy in biomedical applications.