Science of entropy-stabilized ultra-high temperature thin films: Synthesis, validation and properties

The authors report on using multi-cathode magnetron sputtering to fabricate 5-component refractory carbides that are stabilized by configurational entropy to form a robust and high-temperature class of high temperature materials. Magnetron sputtering is an appealing fabrication method as one can prepare layers with high density and the compositional flexibility afforded by five independent metallic sources. Thin layers that comprise mixed carbides of the following elements: W, Mo, Ti, Hf, Zr, Ta, V, and Nb, will be discussed. In all cases sputtering is performed reactively in a gas atmosphere including Ar as the inert sputter gas and propane as the carbon source. Sputter depositions can be conducted between room temperature and 800 °C. The relationship between sputtering parameters including power, pressure, rate, gas mixture, and film properties including density, thermal conductivity, lattice constant, and phase evolution will be discussed. Please click Additional Files below to see the full abstract

Science of high entropy ultra-high temperature thin films: synthesis and characterization

The authors describe the use of a 5-cathode reactive RF magnetron sputtering system to fabricate up to 5-component refractory high entropy carbides which form a robust class of high temperature materials. Magnetron sputtering is an appealing fabrication method it allows for deposition of high density films of many compositions at relatively low temperatures compared to bulk processing techniques. Thin films of mixed carbides consisting of the following elements: Ti, Zr, Hf, Nb, Ta, Mo, and W, will be discussed. All films are sputtered reactively in a gas atmosphere where Ar is the inert sputter gas with methane as the carbon source. Carbon stoichiometry is controlled via methane flow rates and assessed with density measurements. Use of 5 cathodes allows for rapid exploration of the 5 metal composition space from unary to quaternary or quinary carbides in short time spans. Please click Additional Files below to see the full abstract