Synthesis and Characterization of Zirconium Nitride Nanopowders by Internal Gelation and Carbothermic Nitridation

Shijiao Zhao,Xuping Lin,Jingtao Ma,Rui Xu,Xing Cheng,Changsheng Deng,Bing Liu,Shaochang Hao,Xingyu Zhao

doi:10.1038/s41598-019-55450-x

Abstract

Zirconium compounds has been widely attention over the last decades due to its excellent physical and chemical properties. Zirconium nitride nanopowders were synthesized via a simple direct carbothermic nitridation process of internal gel derived zirconia in the presence of nano-sized carbon black. The effects of reaction temperature, dwell time and molar ratio of carbon black to Zr (C/Zr) on the phase composition, grain size and crystal parameters of products were studied. Based upon the analysis of crystallite phase evolution and microstructure characterization, it was found that zirconium oxynitride is intermediate product and then O atoms in oxynitride were extracted by oxygen getter, carbon black. Anion sites were directly replaced by N atoms to form rock-salt type nitride in carbothermic nitridation process.

Highlights

The synthesis of zirconium nitride powders mainly includes direct nitridation of Zr metal with nitrogen[25,26], high energy reactive ball milling (RBM)[27], microwave plasma method[28], benzene-thermal method[29], aluminum reduction nitridation[30], magnesium thermal reduction[31], carbothermic reduction nitridation (CRN)[32], and direct carbothermic nitridation (CN) of zirconia (ZrO2)[33] and zircon[34] etc
Because of the formation of solid solution in the ZrN-zirconium carbide (ZrC)-‘ZrO’ system[40,41], it should be noted that the final nitrided products in CRN or CN are in general represented by the formula Zr(N,C,O)
When the temperature was increased to 1400 °C, sample with Zr(N,C,O) phase was obtained as shown in X-ray diffraction (XRD) pattern

Summary

Introduction

The synthesis of zirconium nitride powders mainly includes direct nitridation of Zr metal with nitrogen[25,26], high energy reactive ball milling (RBM)[27], microwave plasma method[28], benzene-thermal method[29], aluminum reduction nitridation[30], magnesium thermal reduction[31], carbothermic reduction nitridation (CRN)[32], and direct carbothermic nitridation (CN) of zirconia (ZrO2)[33] and zircon[34] etc. CRN process needs two-step heat treatments by which zirconium carbide (ZrC) was first produced as an intermediate before conversion to nitride. CN process is direct nitridation of ZrO2 in the presence of carbon which needs only one heat treatment. The latter could be more energy-efficient and time-saving for preparation of zirconium nitride powders. The effects of nitridation temperature from 1300 °C to 1500 °C, dwell time from 2 h to 5 h, and the molar ratio of carbon black to Zr (C/Zr) from 0 to 3 on the powder characteristics were systematically studied. Combined with phase evolution and microstructure evolution, the role of carbon in the CN process was discussed

Methods

Results

Conclusion