Preparation of Gd2O3 Ultrafine Nanoparticles by Pulse Electrodeposition Followed by Heat-treatment Method

Abstract

Gd₂O₃ nanoparticles were prepared by a two–step process; cathodic electrodeposition followed by heat-treatment method. First, Gd(OH)₃ nanoparticles was galvanostatically deposited from nitrate bath on the steel substrate by pulse current (PC) mode. The deposition experiments was conducted at a typical on-time and off-time (t_on=1ms and t_off=1ms) for 60 min. The electrodeposited precursor was then heat-treated at 600 oC for 3h to obtain oxide product (i.e. Gd₂O₃). The morphological and structural analyses confirmed that the gadolinium hydroxynitrate nanoparticles with composition of [Gd(OH)_2.5(NO₃)_0.5 yH₂O] and uniform size about 10 nm have been prepared during pulse cathodic electrodeposition process. Furthermore, mechanism of the gadolinium hydroxynitrate nanoparticles was explained based on the base (OH–) electrogeneration process on the cathode surface. The morphological observations by SEM and TEM, and structural analyses via XRD and FT-IR revealed that the oxide product is composed of well-dispersed Gd₂O₃ nanoparticles with pure cubic crystalline structure. It was observed that the calcination process has no effect on the morphology of the Gd₂O₃ nanoparticles. Mechanism of oxide formation during heat-treatment step was investigated by DSC-TG analysis and discussed in detail. The results of this work showed that pulse current deposition followed by heat–treatment can be recognized as an easy and facile method for preparation of the Gd₂O₃ fine nanoparticles.