Densification of Vanadium Nitride by Microwave-Assisted Carbothermal Nitridation

Abstract

A microwave carbonthermal nitridation method under the condition of nitrogen at atmospheric pressure was used to the synthesis of vanadium nitride from vanadium pentoxide and carbon black. In the present work, the effects of synthesis temperature, flowing rate of nitrogen, heating rate and soaking time on the apparent density and the nitrogen content of the microwave sintered samples were studied. The experimental data indicated that the apparent density and the nitrogen content of the microwave sinter sample was 4.1 g/cm3 and 13.8 %, respectively under the optimum conditions of flowing rate of nitrogen 50 L/h, heating rate of 6 °C/min to 1400 °C and soaking time of 50 min. The denser pellet was preferred to generated in the centre of the samples of which was beneficial to the expulsion of stoma and the diffusion of nitrogen due to the opposite temperature gradient compared with traditional heating.

Preparation of Vanadium Nitride Using a Thermally Processed Precursor with Coating Structure

“…Although an appropriate flow rate of nitrogen can promote the synthesis of VN, high reaction temperature and long reaction time were still required in the synthesis of VN with the flow of nitrogen in the tubular furnace [11,12]. Compared with a temperature of 1300-1500 °C required to prepare VN by the traditional CRN method, this study permitted a lower temperature and a shorter time by as much as several hundred degrees centigrade and several hours, respectively.…”

“…The traditional procedure for the synthesis of VN is the process of carbothermal reduction-nitridation (CRN) of V 2 O 5 in N 2 at a high temperature of 1500 • C for 3 h with a N 2 flow rate of 13.3 × 10 −6 m 3 · s −1 [11], and at 1400 • C with a N 2 flow rate of 50 L·h −1 , using a microwave method [12]. The low melting point (670 • C) and the high saturation vapor pressure of V 2 O 5 will result in a volatile loss of V 2 O 5 near its melting point.…”