Abstract

SANTIAGO-BAUTISTA, Lourdes et al. Coating growth on 304 stainless steel fractures by the Pechini method. Ing. invest. y tecnol. [online]. 2018, vol.19, n.4, e032. ISSN 2594-0732.  https://doi.org/10.22201/fi.25940732e.2018.19n4.032.

This study presents the first results of Ni-rich coating growth by the Pechini method on 304 stainless steels fractures, in order to healing fracture surfaces of metallic parts. A series of tests were performed to establish the calcination temperature by differential scanning calorimetry (DSC) at 1300°C using a heating rate of 10°C/min in mixtures of (CH3COO)2Ni•4H2O (Nickel Acetate Tetrahydrate) with HOC(COOH)(CH2COOH)2•H2O (Citric Acid Monohydrate) and precursors: HOCH2CHOHCH2OH (Glycerol) and HOCH2CH2OH (Ethyleneglycol). Results indicate that the Ethyleneglycol precursor is better than the Glycol because it shows a thermal stability at lower temperature of calcination. Subsequently, 304 stainless steel cylindrical fractures (0.6 cm in diameter, 1 cm height) were immersed in a solution of Ethyleneglycol and these samples were gelated at 110°C for 24 h in a muffle furnace. Additionally, these samples were calcined at 660°C for 60 min under an Ar flow of 200 ml/min, using a heating/cooling rate of 5°C/min in order to synthesize the nickel nanoparticles on the fractures. Coating growth on the fractures was carried out at an Ar flow of 220 ml/min at 1100°C for 60 min at a heating/cooling rate of 10°C/ min. By optical and scanning microscopy MEB), it was observed that the coating has a thickness of ~700 μm with a series of cuboidal precipitates larger than 1 μm, as well as laminar phases rich in Ni, Fe and Cr.

Keywords : Pechini method; stainless steel; fracture; nickel; nanoparticles.

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