Synthesis and Mechanical Characterization of a CuMoTaWV High-Entropy Film by Magnetron Sputtering

Abstract

Development of high-entropy alloy (HEA) films is a promising and cost-effective way to incorporate these materials of superior properties in harsh environments. In this work, a refractory high-entropy alloy (RHEA) film of equimolar CuMoTaWV was deposited on silicon and 304 stainless-steel substrates using DC-magnetron sputtering. A sputtering target was developed by partial sintering of an equimolar powder mixture of Cu, Mo, Ta, W, and V using spark plasma sintering. The target was used to sputter a nanocrystalline RHEA film with a thickness of ∼900 nm and an average grain size of 18 nm. X-ray diffraction of the film revealed a body-centered cubic solid solution with preferred orientation in the (110) directional plane. The nanocrystalline nature of the RHEA film resulted in a hardness of 19 ± 2.3 GPa and an elastic modulus of 259 ± 19.2 GPa. A high compressive strength of 10 ± 0.8 GPa was obtained in nanopillar compression due to solid solution hardening and grain boundary strengthening. The adhesion between the RHEA film and 304 stainless-steel substrates was increased on annealing. For the wear test against the E52100 alloy steel (Grade 25, 700–880 HV) at 1 N load, the RHEA film showed an average coefficient of friction (COF) and wear rate of 0.25 (RT) and 1.5 (300 °C), and 6.4 × 10–6 mm3/N m (RT) and 2.5 × 10–5 mm3/N m (300 °C), respectively. The COF was found to be 2 times lower at RT and wear rate 102 times lower at RT and 300 °C than those of 304 stainless steel. This study may lead to the processing of high-entropy alloy films for large-scale industrial applications.

CoCrFeNi High-Entropy Alloy Thin Films Synthesised by Magnetron Sputter Deposition from Spark Plasma Sintered Targets

“…A suitable method to form homogeneous, large area thin films is magnetron sputtering. HEAs have already been successfully sputtered from mosaic targets [8,9], loosely pressed powder targets [10][11][12] or sintered targets [13][14][15]. However, to the best of our knowledge, a direct comparison of HEA films fabricated from two differently prepared sputter targets used in the same system under equal conditions has not been reported so far.…”

Tribological Performance of High-Entropy Coatings (HECs): A Review

“…At elevated temperature (600 °C), the formation of CuO and excessive oxidation of V-rich phase resulted in a low COF but slightly higher wear rate. Alvi et al [ 156 ] synthesized the CuMoTaWV film by means of magnetron sputtering methods from a single partially spark-plasma-sintered targe in subsequent studies. The authors evaluated the mechanical and tribological properties of these sputtered films.…”

Recent Advances in Alkaline Exchange Membrane Water Electrolysis and Electrode Manufacturing

“…In addition, MS provides a strict control of composition and load of the catalyst film on the electrode. Using this one-step preparation technique, it is possible to prepare a large variety of chemical compounds: single metals [117,118], metal alloys from a single-target with the desired composition [119] or by co-sputtering using more than one target [120], oxides by reactive magnetron sputtering adding oxygen to the plasma discharge [31], nitrides, using N 2 as reactive gas [121], etc. Additionally, control over the deposited microstructure is also possible, varying the angle of the particle flux with respect to the surface normal, i.e., by means of oblique angle deposition (OAD) [114].…”