Title: Effect of N and C on surface formation of jagged - nodular and nitride-carbide structure on hard chrome steel during thermochemical treatment

Authors: Komang Astana Widi; Ing Wardana; Wahyono Suprapto; Yudy Surya Irawan

Addresses: Mechanical Engineering Department, National Institute of Technology National of Malang, East Java, Indonesia ' Mechanical Engineering Department, Brawijaya University, Malang, East Java, Indonesia ' Mechanical Engineering Department, Brawijaya University, Malang, East Java, Indonesia ' Mechanical Engineering Department, Brawijaya University, Malang, East Java, Indonesia

Abstract: The morphology of surface structure was changed from jagged to nodular structure. Martensite structure is formed from hard chrome plating after the oxidised diffusion of nitriding process. The investigation was conducted using SEM, EDAX, AFM and spectroscopy. This phenomenon belongs to an unusual structure. The morphology of crack density that disappears depends on the diffusion media of nitriding process. Such phenomena also happened under hard chrome plating forming carbide and bainite structure. With the changed structure of layers plating, friction and wear characteristic of hard chrome plating became better. Hard chrome coated tool steel substrate of AISI 4140 type was nitridised (550ºC, 4 hours of boost phase and 2 hours of diffusion phase) without gas diffusion media. The analysis of AFM shows the roughness value of the surface was increase after the treatment of nitriding. The nodular structure would provide width of oil storage as greater self lubricant. The structure formed can be illustrated like an area of farm. The structure could also omit the jagged area. The mechanism of nitrogen atom deposition that is interesting and relatively new was observed in this research as well.

Keywords: nodular; carbide; crack density; AFM; roughness; nitriding; hard chrome; morphology; self lubricant; SEM; EDAX.

DOI: 10.1504/IJMATEI.2016.084635

International Journal of Materials Engineering Innovation, 2016 Vol.7 No.3/4, pp.271 - 284

Received: 19 Nov 2016
Accepted: 05 Jan 2017
Published online: 19 Jun 2017 *

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