Synthesis and characterization of thin copper coatings obtained by sonoelectrodeposition method

Abstract

Influence of an intensity of ultrasonic mixing of electrolyte in a temperature range of 27–37 °C and ultrasonic power intensity in the range of 3.77–18.84 W/cm2 (10–50 %) on a synthesis of fine-grained copper deposits was examined. Copper coatings were electrodeposited on a brass substrate in direct current (DC) regime with an applied current density of 50 mA·cm-2. The laboratory-made copper sulfate electrolyte was used without or with addition of additives. The variation of temperature under sonoelectrodeposition process and variation mixing intensity of electrolyte were ensured by using an ultrasonic probe. The produced Cu coatings were examined by optical microscope (OM) in order to observe the microstructural modification with variation ultrasonic parameters and for measuring imprints of Vickers indenter. The micro hardness properties of composite systems were characterized using Vickers micro indentation test. The composite hardness models Chicot-Lesage and Chen-Gao were used for the determination the coatings hardness and adhesion evaluation. Application of Atomic Force Microscopy (AFM) technique also confirmed the strong influence of ultrasonic mixing conditions of electrolyte onto change of the microstructure of copper deposits and surface roughness of the coatings. The maximum hardness, good adhesion properties and minimum micro surface roughness was obtained for the fine-grained Cu coating produced with amplitude of 50 % ultrasonic mixing of electrolyte without additives and 30 % for electrolyte with additives.