Bipolar high-power impulse magnetron sputtering synthesis of high-entropy carbides

Mohammad Delower Hossain, Trent Borman, Nathaniel Seymour Mcllwaine, Jon Paul Maria

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

In this study, we report high-entropy carbides synthesis with reactive bipolar high-power impulse magnetron sputtering (HiPIMS). Uncontrolled microstructure and stoichiometry development with reactive gas flow rate are major limitations of conventional direct current (DC) and radio frequency (RF) magnetron sputtering of multicomponent carbides. With HiPIMS these chemically disordered crystals structurally and compositionally transform from a carbon-deficient metallic (C/M < 1), to a stoichiometric ceramic zone (C/M ∼ 1), and to a nanocomposite embodiment (C/M > 1), as a function of the carbon content during HiPIMS deposition. X-ray diffraction, X-ray photoelectron spectroscopy, Raman spectroscopy, scanning electron microscopy, and nanoindentation hardness measurements are combined to demonstrate the three regions of synthesis domain. HiPIMS provides access to metallic, ceramic, and composite carbides with great control over the microstructure and stoichiometry, which is elusive in case of conventional DC and RF magnetron sputtering. Notably, the stoichiometric ceramic zone maintains a constant carbon to metal ratio (C/M ∼ 1) over an extended amount of methane flow before transitioning to a nanocomposite microstructure (C/M > 1). The transition zone breadth depends on materials affinity for carbon that correlates with valence electron concentration (VEC). As such, synthesis conditions for new high-entropy carbides can be understood and predicted based on VEC.

Original languageEnglish (US)
Pages (from-to)3862-3873
Number of pages12
JournalJournal of the American Ceramic Society
Volume105
Issue number6
DOIs
StatePublished - Jun 2022

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry

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