Analysis of tungsten film electrodeposited from a ZnCl2–NaCl–KCl melt

Microparts for micro-electro-mechanical systems (MEMS) are becoming increasingly important, and the Lithographie Galvanoformung Abformung (LIGA) process for producing such parts is attracting attention [1]. However, as this process requires the step of electroplating in aqueous solution, only copper, nickel and their alloys can be used because of the limit of the potential window of water. We have been attempting to apply the electroplating of refractory metals in molten salts to the LIGA process or to the surface coating of conventional LIGA microparts in order to give higher strength and heat resistance for the microparts. Herein we report the characteristics of a tungsten film electrodeposited from a ZnCl2–NaCl–KCl melt at 250 °C.