Tribocorrosion behavior of boride coating on CoCrMo alloy produced by thermochemical process in 0.35% NaCl solution

• Published in: Surface & coatings technology Vol. 425; p. 127698
• Main Authors: Doñu-Ruiz, M.A., López-Perrusquia, N., Renteria-Salcedo, A., Flores-Martinez, M., Rodriguez-De Anda, E., Muhl, S., Hernández-Navarro, C., García, E.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 15.11.2021; Elsevier BV
• Subjects: Alloys; Boriding; Boronizing process; CoB and Co2B phase; Cobalt base alloys; Coefficient of friction; Corrosion resistance; Corrosion resistant alloys; Dehydration; Sodium chloride; Thermochemical treatments; Tribocorrosion; Tribology; Wear rate; Boronizing process; Thermochemical treatments; Tribocorrosion; CoB and Co2B phase
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/j.surfcoat.2021.127698

The boriding thermochemical process is a favorable option to produce protecting layer in metallic alloys surfaces. This work presents the corrosion and tribological studies of boride and un-boride surfaces of CoCrMo alloy. These results showed that the boronizing process was produced with the dehydrated boron past at 850 °C for 2 h. This process generated CoB, Co2B, and CrB phases in the alloy surfaces and increased the roughness (Ra) value. The boride surfaces presented a hardness of 30 ± 3.7 GPa with lower corrosion resistance than the CoCrMo alloy in 3.5% NaCl solution in distillate water. The wear rate and coefficient of friction were similar for the boride layer at 2, 3, and 4 N in dry conditions, nevertheless the coefficient of friction decrease in the corrosive environment with a lower wear rate than the un-boride surfaces due to the formation of a tribolayer that protected the contact zone. [Display omitted] •The boriding process to CoCrMo alloy samples generated the formation of the CoB, Co2B and CrB phases in the substrate surfaces.•The boride surfaces presented a lower corrosion resistance than the CoCrMo alloy.•The corrosion process reduced the pretense of CoB and Co2B phase in the surfaces.•The boride surfaces presented a lower ware rate and similar CoF than the CoCrMo alloy during the sliding-contact tests.•During the rubbing period, the contact area on the boride surfaces was protected by a tribolayer.