Structure and Frictional Properties of Ultrahard AlMgB14 Thin Coatings

Abstract

This paper presents the results of studies on AlMgB14-based ceramic coatings deposited on WC-Co hard alloy substrates using RF plasma sputtering. The aim of this work is to study the structure, phase composition, and mechanical properties of AlMgB14-based coatings depending on the sputtering mode. According to the results of the microstructural study, the bias voltage applied to the substrate during the sputtering process significantly contributed to the formation of the coating morphology. Based on the results of compositional and structural studies by energy dispersive X-ray spectroscopy, X-ray diffraction, and Raman spectroscopy, it was found that the coatings are composed of nanocrystalline B12 icosahedrons distributed in an amorphous matrix consisting of Al, Mg, B, and O elements. The nanohardness of the coatings varied from 24 GPa to 37 GPa. The maximum value of the hardness together with the lowest coefficient of friction (COF) equal to 0.12 and wear resistance of 7.5 × 10−5 mm3/N·m were obtained for the coating sputtered at a bias voltage of 100 V. Compared with the COF of the original hard alloy substrate, which is equal to 0.31, it can be concluded that the AlMgB14-based coatings could reduce the COF of WC-based hard alloys by more than two times. The hardness and tribological properties of the coatings obtained in this study are in good agreement with the properties of AlMgB14-based materials obtained by other methods reported in the literature.

Research on the Tribological Properties of a New Generation of Multi-Layer Nanostructured PVD Coatings for Increasing the Technological Lifetime of Moulds

“…The sliding properties were even improved, which was reflected in the drop in the COF to a value of 0.15. The properties of the PVD coatings obtained in this study are comparable to those of similar materials reported in the literature [28].…”

Hard and Highly Adhesive AlMgB14 Coatings RF Sputtered on Tungsten Carbide and High-Speed Steel

“…The most recent advances and new results include the following: hard and lubricant BAM films produced by DC magnetron sputtering of three elemental targets (B, Mg, Al) [16], employing the process of RF plasma sputtering of AlMgB 14 powder targets [17], AlMgB 14 /TiB 2 composite ceramic brazed onto 304 stainless steel using a commercial Ag-CuTi eutectic foil [18], examination of BAM-coated twist drill wear, the evolution of cuttingedge geometry in drilling experiments with carbon-fiber-reinforced plastic (CFRP) laminate [19] and the novel application of BAM-based ceramic coatings onto the blade edges of razor blades [20] and onto the surfaces of rolling elements in bearing assemblies [21]. Especially noteworthy is the deep nanostructural characterization of the mechanical-tribological behavior and the analysis of the wear rate of nanocomposite TiSiCN coatings deposited on high-Co-based high-speed steel (ASSAB 17) burins [22].…”