Microchemical and microstructural changes of nano-TiN powder during vacuum heat treatment

In the paper, effect of vacuum heat treatment on the chemical composition, microstructure and morphology of nano-TiN powder was investigated. Nano-TiN powders were heat treated in vacuum at 1200 °C for 1 h. XPS, XRD and TEM were used to characterize the surface chemical composition, lattice parameter and morphology of as-received and as-treated nano-TiN. The results showed that the oxygen content adsorbed by nano-TiN powder was largely decreased from 6.64 wt% to 1.18 wt% after heat treatment. The nano-TiN maintained the face-centered cubic structure except a slight decrease of lattice parameter. The average particle size increased from 20 nm to 40 nm, indicating growth of nano-TiN particles during the vacuum heat treatment.

Research highlights▶ At present, the deteriorating effect of oxygen contamination on the nano-TiN powder is well known but relatively little attention has been paid on the deoxidation process of nano-scaled TiN powder in vacuum. ▶ Many literatures reported that the oxygen content of micro-scaled powder can be successfully decreased by heating in vacuum. However, little attention has been paid on the microchemical and microstructural changes of nano-powder after vacuum heat treatment at high temperature.