CoxCrFeNiTi High-Entropy Alloys Prepared via Mechanical Alloying and Spark Plasma Sintering for Magnetron Sputtering Coatings

Ciprian Alexandru Manea; Laura Elena Geambazu; Dorinel Tălpeanu; Virgil Marinescu; Gabriela Beatrice Sbârcea; Delia Pătroi; Radu Mihail Udrea; Magdalena Valentina Lungu; Mariana Lucaci

doi:10.3390/ma16196386

Co_xCrFeNiTi High-Entropy Alloys Prepared via Mechanical Alloying and Spark Plasma Sintering for Magnetron Sputtering Coatings

Materials (Basel). 2023 Sep 24;16(19):6386. doi: 10.3390/ma16196386.

Affiliations

¹ National Institute for R&D in Electrical Engineering ICPE-CA Bucharest, Splaiul Unirii 313, 030138 Bucharest, Romania.
² Material Science and Engineering Faculty, University Politehnica Bucharest, Splaiul Independentei 313, 060042 Bucharest, Romania.
³ APEL LASER.SRL, Str. Vanatorilor 25, 077135 Mogosoaia, Romania.

Abstract

The main objective of this study was to develop a high-entropy alloy (HEA) derived from the Co_xCrFeNiTi HEA system (x = 0.5, 1) for protective coatings using the magnetron sputtering method. In order to produce the high-entropy alloy targets required for the magnetron sputtering process, mechanically alloyed metallic powders were consolidated via spark plasma sintering (SPS). The microstructural analysis results of the HEA mixture presented morphology changes after 30 h of alloying, with the particles presenting uniform polygonal shapes and dimensions. Subsequently, 316L stainless steel (SS) specimens were coated via magnetron sputtering, comparing their composition with that of the sputtering targets used for deposition to establish stoichiometry. Microstructural analyses of the SPSed HEAs revealed no defects and indicated a uniform elemental distribution across the surface. Furthermore, the CoCrFeNiTi equiatomic alloy exhibited a nearly stoichiometric composition, both in the coating and the sputtering target. The XRD analysis results indicated that amorphous coatings were obtained for both Co_0.5CrFeNiTi and the CoCrFeNiTi HEA, and nanoindentation tests indicated that the CoCrFeNiTi HEA coating presented a hardness of 596 ± 22 HV, compared to the 570 ± 19 HV measured for Co_0.5CrFeNiTi, suggesting an improved wear resistance.

Keywords: high-entropy alloy; magnetron sputtering; mechanical alloying; spark plasma sintering.

Grants and funding

This research was funded by the “POC” PROGRAM, Axis 1, Action: A1.2.3, named: “Development of intellectual capital through knowledge transfer in the field of advanced materials—Impact on the increase of labour productivity and the volume of production in enterprises”. Project acronym: PHOENIX, project ID: P_40_403, My SMIS code: 105568, No. Contract: 133/23.09.2016, subsidiary contract: 133 D7 APEL/2022 entitled “Functional depositions (resistant to corrosion/wear) from high entropy alloys”, with the acronym HEA-DF. The APC was funded by PFE Contract No. 25/2021.