LAUSR

Electrodeposition of Al­W alloy films with high W contents has been carried out using 1-ethyl-3-methylimidazolium chloride (EMIC)­ aluminum chloride (AlCl3) ionic liquids containing tungsten(II) chloride (W6Cl12). Although the corrosion resistance and hardness of the alloy films are expected to be improved with an increase in the W content, dense films with W contents higher than 312 at% have not been obtained by electrodeposition to date. This study has demonstrated that electrodeposition using a EMIC­AlCl3­W6Cl12 bath with a lower AlCl3/EMIC molar ratio can yield Al­W alloys with higher W contents. The maximum W content of the alloys electrodeposited using the EMIC­1.5AlCl3 bath reached 19.4 at%. The alloy films with up to 318 at% W were dense and smooth, whereas those with >318 at% W exhibited increased surface roughness. The hardness and Young’s modulus of the dense and smooth 17.7 at% W film were determined by nano-indentation. The hardness of this film was confirmed to be higher than those of the Al­W alloy films previously obtained from the EMIC­2AlCl3 baths. [doi:10.2320/matertrans.M2018051]