Surface Characterization and Boriding of Nickel and Cobalt Alloys

• Published in: Protection of metals and physical chemistry of surfaces 2022-08, Vol.58 (4), p.772-778
• Main Author: Yildiz, Ismail
• Format: Article
• Language: English
• Subjects: Alloys; Boriding; Characterization and Evaluation of Materials; Chemistry and Materials Science; Coatings; Cobalt base alloys; Corrosion and Coatings; Diamond pyramid hardness; Industrial Chemistry/Chemical Engineering; Inorganic Chemistry; Magnesium; Materials; Materials Science; Metallic Materials; New Substances; Nickel; Surface properties; Surface roughness; Thickness; Tribology
• ISSN: 2070-2051; 2070-206X
• DOI: 10.1134/S2070205122040244

In this work, Cobalt-Magnesium (93% Co–7% Mg; CM) and Nickel-Magnesium (93% Ni–7% Mg; NM) alloys were successfully borided by pack boriding at the temperature range of 900°C for 1.5 and 4.5 h. The characteristics of boride layers were examined by X-ray diffraction, scanning electron microscopy, surface roughness, density and microhardness tester. After boronizing, the major dominant phase were found to be NiB for NM alloys and Co 2 B for CM alloys. Boride coating resulted in smooth and dense feature confirmed by SEM. The thickness of boride layer varied from 47.96 to 145.21 μm for CM alloy and 67.21 to 179.84 μm for NM alloy depending on the process time. Boride layer has a hardness varied from 1752 to 1865 HV 0.05 for CM alloy and 1634 to 1768 HV 0.05 for NM alloy, whereas the Vickers hardness value of the untreated Cobalt and Nickel were 194 HV 0.05 and 118 HV 0.05 respectively. Co x O y , Ni x O y and Mg x O y phases were formed as a result of EDX analysis after the wear test.