Thermal analysis kinetics of thermal decomposition of nickel–viscose composite fiber

Abstract

In this study, the thermal decompositions of nickel composite fibers (NCF) under different atmospheres of flowing nitrogen and air were investigated by XRD, SEM–EDS, and TG–DTG techniques. Non-isothermal studies indicated that only one mass loss stage occurred over the temperature regions of 298–1,073 K in nitrogen. The mass loss was from the decomposition. But after this decomposition, nickel was oxidized in air, when the temperature was high enough. In nitrogen media, the model-free kinetic analysis method was applied to calculate the apparent activation energy (E a) and pre-exponential factor (A). The method combining Satava–Sestak equation with one TG curve was used to select the suitable mechanism functions from 30 typical kinetic models. Furthermore, the Coats–Redfern method was used to study the NCF decomposition kinetics. The study results showed that the decomposition of NCF in nitrogen media was controlled by three-dimension diffusion; mechanism function was the anti-Jander equation, the apparent activation energy (E a) and the pre-exponential factor (A) were 172.3 kJ mol−1 and 2.16 × 109 s−1, respectively. The kinetic equation could be expressed as following: $$ \frac{{{\text{d}}\alpha }}{{{\text{d}}T}} = \frac{{ 2. 1 6\times 1 0^{ 9} }}{\beta }{ \exp }\left( {\frac{ - 2 0 7 2 4. 1}{T}} \right)\left\{ {\frac{ 3}{ 2}(1 + \alpha )^{2/3} [(1 + \alpha )^{1/3} - 1]^{ - 1} } \right\}. $$