Copper-Molybdenum Source Ratio and Complexing Agent for High Molybdenum Content in Electrodeposited Cu-Mo

Abstract

Cu-Mo composites have been one of candidates for material of heat-sinks in electronic devices. We obtained Cu-Mo composites by electrodeposition using CuSO 4 and Na 2 MoO 4 with trisodium citrate as complexing agent. The presence of molybdenum in Cu-Mo was demonstrated by X-ray photoelectron spectroscopy and inductively coupled plasma atomic emission spectroscopy. The molybdenum content in Cu-Mo composites depended on the concentration ratio of Na 2 MoO 4 /(Na 2 MoO 4 + CuSO 4 ) in the electrolyte, kinds and concentration of complexing agents. The mol ratio of Na 2 MoO 4 /(Na 2 MoO 4 + CuSO 4 ), from 0.75 to 0.87 provided larger molybdenum content at 0.05 A/dm 2 of electrodeposition current. The molybdenum content increased with decreasing current density during electrodeposition in the range of 0.05-0.3 A/dm 2 . Trisodium citrate was the most effective complexing agent among trisodium citrate, glycolic acid, EDTA (4Na) and combinations of them for increasing molybdenum content. The molybdenum content reached up to 22.9 wt% at 0.396 mol/dm 3 of trisodium citrate concentration. X-ray diffraction shows that no peaks related to molybdenum was observed, moreover, the intensity and the width of Cu(111) peaks decreased and enlarged with increasing molybdenum content. These indicate that the structure of molybdenum in copper-molybdenum composites was amorphous, furthermore, higher molybdenum content made copper structure close to amorphous.

Electrodeposition study of the Cu-Zn-Mo system in citrate/sulfate medium

“…This irregularity was attributed to the diffraction of plane (200) of the Cu with low crystallinity, which might have been caused by the introduction of amorphous Mo into the lattice of this metal. According to Gotou et al 17 , molybdenum can be introduced into the crystal lattice of the copper, causing an enlarging of lattice space and leading to an amorphous structure. Therefore, the Cu-Zn-Mo coatings obtained in this work were a mixture of Cu-Zn intermetallic phases and coppermolybdenum amorphous composites, as well as Mo oxides with fully amorphous characteristics.…”

“…Recent research shows the possibility of Mo deposition with Zn and Cu 14,[16][17][18] . In these studies, the Zn-Mo composite is proposed as a corrosion resistant coating with low danger and environmentally friendly, in contrast to other anticorrosive alloys containing cadmium and chromium.…”

“…In their turn, Cu-Mo compounds can be used as heat sinks or heat diffusers in electronic devices. Gotou et al 17 studied this system and obtained coatings with up to 22% m/m Mo with amorphous features, regardless of the amount of Mo in the coatings. Thus, a few studies have reported on Cu-Mo and Zn-Mo binary composites; however, there has been no report of Cu-Zn-Mo ternary system obtained by electrodeposition.…”

Optimization of CuW alloy electrodeposition towards high-tungsten content

“…Recently, the number of announcements reporting on electrodeposition of tungsten and molybdenum with transition metals other than the iron-group metals [16][17][18] is growing. Our results indubitably proved that a CuW alloy can be obtained by simultaneous electroreduction and deposition of tungsten with copper.…”