Effect of zinc nickel coating on properties of Nitrided AISI 1040 steel

• Published in: Materials research express Vol. 6; no. 8; pp. 86547 - 86559
• Main Authors: Kumar, M S, Ragunathan, S, Velu, P Shenbaga, Suresh, M, Srinivashan, V R, Kumaravel, P
• Format: Journal Article
• Language: English
• Published: IOP Publishing 08.05.2019
• Subjects: corrosion; fatigue; nitriding; pulse plating; SEM; wear; zinc-nickel coating
• ISSN: 2053-1591; 2053-1591
• DOI: 10.1088/2053-1591/ab195b

In this present work, influence of Zn-Ni coating on AISI 1040 steel and Nitrided AISI 1040 steel is discussed. Micro-hardness, Coating thickness and wear were tested. Surface morphology, grain size and element composition have been measured using SEM, XRD and EDS analysis. Corrosion characteristics have been studied with concentration of 5.2%-5.4% NaCl environmental condition and adhesion was conducted by cross hatch method. The corrosion study reveals that the coated specimen shows metal removal rate at the end of 63 h with weight loss of 0.21%. This corrosion resistance is 3 times better than the un-coated AISI 1040 steel also it is better than individual nitrided steel. The corrosion study of Zn-Ni coating on Nitrided AISI 1040 steel states that there is no corrosion takes place up to 42 h and metal removal rate is observed at the end of 42 h with weight loss of 0.82%. Fracture morphology on the base metal shows the transgranular fracture and cracks are initiated from the surface and propagated towards the core of the specimen and represent the general fracture surface. Crack nucleation at interface of Zn-Ni coating and AISI 1040 steel surface is observed and the specimen shows transgranular ductile fracture. Brittle fracture occurred at the hardened layer in individual nitriding process has been nucleated at the interface of Zn-Ni coating and nitrided layer zone and also this brittle fracture has been transited to ductile towards the core of the specimen. Finally, the endurance limit and life of all categories are compared. It has been concluded that Zn-Ni coating on AISI 1040 steel increases endurance limit by 8.34% and Zn-Ni coating on Nitrided steel increases endurance limit by 36.67%.