Microstructural, Corrosion Resistance, and Tribological Properties of Al2O3 Coatings Prepared by Atmospheric Plasma Spraying

Costică Bejinariu; Viorel Paleu; Ciprian Vasile Stamate; Ramona Cimpoesu; Margareta Cimpoesu; Gheorghe Badarau; Mihai Axinte; Bogdan Istrate; Gabriel Dragos Vasilescu; Nicanor Cimpoeșu

doi:10.3390/ma15249013

Microstructural, Corrosion Resistance, and Tribological Properties of Al₂O₃ Coatings Prepared by Atmospheric Plasma Spraying

Materials (Basel). 2022 Dec 16;15(24):9013. doi: 10.3390/ma15249013.

Affiliations

¹ Materials Science and Engineering Faculty, Gheorghe Asachi Technical University of Iasi, 700050 Iasi, Romania.
² Mechanical Engineering, Mechatronics and Robotics Department, Mechanical Engineering Faculty, Gheorghe Asachi Technical University of Iasi, 700050 Iași, Romania.
³ Faculty of Machine Manufacturing and Industrial Management, Gheorghe Asachi Technical University of Iasi, 700050 Iasi, Romania.
⁴ "INSEMEX" National Institute for Research and Development in Mine Safety and Protection to Explosion, 332029 Petrosani, Romania.

Abstract

An usual material, EN-GJL-250 cast iron, used for automotive braking systems, was covered with a ceramic material (105NS-1 aluminium oxide) using an industrial deposition system (Sulzer Metco). The main reason was to improve the corrosion and wear (friction) resistance properties of the cast-iron. Samples were prepared by mechanical grinding and sandblasting before the deposition. We applied two and four passes (around 12-15 µm by layer) each at 90° obtaining ceramic coatings of 30 respectively 60 µm. The surface of the samples (with ceramic coatings) was investigated using scanning electron microscopy (SEM), dispersive energy spectroscopy (EDS) and X-ray diffraction (XRD). Scratch and micro-hardness tests were performed using CETR-UMT-2 micro-tribometer equipment. The better corrosion resistance of the base material was obtained by applying the ceramic coating. The results present a better corrosion resistance and a higher coefficient of friction of the coated samples.

Keywords: AFM; Al2O3; EDS; SEM; coatings; plasma spraying.

Grants and funding

Part of this work was supported by a grant of the Ministry of Research, Innovation and Digitization, CNCS—UEFISCDI, project number PN-III-P1-1.1-PD-2021-0208, within PNCDI III; Ministry of Research, Innovation and Digitization, project FAIR_09/24.11.2020, the Executive Agency for Higher Education, Research, Development and Innovation, UEFISCDI, ROBIM, project number PN-III-P4-ID-PCE2020-0332.