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We demonstrate a sustainable post-processing of carbon fiber reinforced epoxy polymer (CFRP) composites by air plasma etching that permits regular electroconductive surface patterning through direct Cu galvanic metallization, in contrast to the untreated composite. Our study reveals a significant property dependence of the composite with respect to the position to the fiber/matrix composite surface and treatment. The enhancement in electrical conductivity was not compromised by the lower structural integrity of the composite, as the embedded carbon fibers remained unaffected by the air plasma etching process. The metallized Cu domains on the composite exhibit good hardness and excellent solderability potential. Thus, the electroconductive surface patterning of the composite, preceding galvanic metallization, facilitates the selective deposition of Cu layer domains. This step by step process, relying on the creation of selective electroconductive areas on the composite by plasma etching, enables galvanic metallization. Consequently, it enhances the potential for multifunctional composite applications. The feasibility of galvanic metallization brings new perspectives in selective metallization of composites by allowing the tailoring of the metal layer thickness, microstructure and selection of the metal. [Display omitted] • Air plasma etching encompasses surface pattering of the carbon fiber reinforced polymers. • The electrical conductivity was promoted by surface exposed carbon fiber network enabling multifunctionality of the composite. • Metallized Cu layer domains on the composite exhibit good hardness and excellent solderability potential. [ABSTRACT FROM AUTHOR]

High entropy alloy (HEA) thin films are potential candidates to act as diffusion barrier between Cu and Si in microelectronics. To evaluate the suitability of refractory HEAs, six different HEA thin films based on the MoNbTaW system and alloyed with Ti, V, Cr, Mn, Zr or Hf have been deposited by high power impulse magnetron sputtering with a thickness of 20 nm on Si substrates. The bi-layer architecture was completed by a 150 nm thick top-layer of Cu. The microstructure of the bi-layers before and after annealing in vacuum up to 800 °C was investigated by X-ray diffraction to observe possible phase changes or formations. In addition, resistance measurements and confocal laser scanning microscopy were employed to check for potential barrier failure. The lowest onset temperature for barrier failure of 600 °C was found for MoNbTaWZr, whereas the highest of 700 °C was observed for CrMoNbTaW. The obtained results for the failure temperature are discussed in terms of microstructure, strain and cohesive energy of the HEA films as well as the enthalpy of mixing between the elements in the HEA and Cu. A direct correlation between the mixing enthalpy of the fifth alloying element with Cu and the barrier failure temperature was observed. [Display omitted] • Suitability of refractory high entropy alloys as diffusion barriers. • Synthesis by high power impulse magnetron sputtering. • Best barrier performance for CrMoNbTaW with failure temperature at 750 °C • No correlation between film microstructure and diffusion barrier performance. • Mixing enthalpy of elements in HEA with Cu plays decisive role. [ABSTRACT FROM AUTHOR]

The influence of nitrogen incorporation on the chemical composition, structure, mechanical, and electrical properties of refractory (MoNbTaVW) 1−x N x high entropy alloy thin films is investigated. The films were synthesized by two different physical vapor deposition methods, cathodic arc deposition and direct current magnetron sputtering, onto silicon and polyimide substrates. Regardless of the deposition method, a change from body centered cubic to face centered cubic structure was observed with increasing nitrogen content in the film. This structural change was accompanied by an increase in hardness as measured by nanoindentation but also by a material embrittlement as determined from tensile straining tests. • Synthesis of (MoNbTaVW) 1-x N x films by cathodic arc and sputtering. • Phase transition from body to face centered cubic with increasing N content. • Phase formation is entirely controlled by the metal to N ratio in the film. • Structural change accompanied by increase in hardness and embrittlement. [ABSTRACT FROM AUTHOR]