The Properties of Cr-Al-N Based Coatings Formed on AISI D2 Steel by Thermo-Reactive Diffusion Technique
B. Kılınca, U. Senb and S. Senb
aDepartment of Metallurgical and Materials Engineering, Institute of Arts and Sciences, Sakarya University, Sakarya, Turkey
bDepartment of Metallurgical and Materials Engineering, Engineering Faculty, Sakarya University, Esentepe Sakarya, Turkey
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In this study, chromium aluminum nitride coating was applied on pre-nitrided AISI D2 steel by the thermo-reactive deposition technique in a powder mixture consisting of ferrochromium, aluminum, ammonium chloride, and alumina at 1000°C for 2 h. Steels were gas nitrided for the purpose to enrich the surfaces with nitrogen of the steels in a nitrogen and ammonia atmosphere at 560°C for 8 h. The effect of aluminum content in the powder mixture on the Cr-Al-N layer properties was investigated. The coated samples were characterized by X-ray diffraction analysis, scanning electron microscope, and micro-hardness tests. Chromium aluminum nitride layer formed on the pre-nitrided AISI D2 steel was compact and homogeneous. Electron dispersive spectrometer results showed that coating layer includes chromium, aluminum, and nitrogen. X-ray studies showed that the phases formed in the coating layers on the steel surfaces are Cr2N, (Cr,Fe)2N1 - x, AlN, and Fe2N. The depth of the Cr-Al-N layer ranged from 10.01 ± 1.2 to 13.2 ± 1.7 μm, depending on the aluminum content. The hardness of the coated layers produced on AISI D2 steel are changing from 1743 ± 150 HV0.01 to 2067 ± 160 HV0.01 depending on bath compositions.

DOI: 10.12693/APhysPolA.123.271
PACS numbers: 81.15.-z, 62.20.Qp, 68.55.J-, 81.65.Lp