Preparation of Cr2O3 nanoparticles via surfactants-modified precipitation method and their catalytic effect on nitridation of silicon powders

Abstract

Cr2O3nanoparticles (NPs) were successfully prepared by a facile surfactant-modified precipitation method, and their phase composition and microstructure were characterized by X-ray diffraction, field emission-scanning electron microscopy and transmission electron microscopy. The effects of various processing parameters including surfactants type and amount, pH value and firing temperature on the synthesis of Cr2O3NPs were investigated. Highly dispersed Cr2O3NPs with an average crystalline size of 17nm were obtained under the following optimal conditions: [Cr(NO3)3·9H2O] = 0.0316 mol/L, PEG/Cr2O3= 5wt%, pH = 5.2, calcination temperature = 500°C and holding time = 2h. Cr2O3NPs showed a significant accelerating effect on the nitridation of Si powder, the conversion rate of Si to Si3N4after 2 h at 1300°C reached 100wt% upon using 3wt% Cr2O3NPs as catalysts, but only 40wt% in the case without using any catalysts.