Effect of synthesis parameters on the crystallite size of WC-Ni composite powders obtained by gas-solid reaction

Abstract

WC-Ni nanoparticles were synthesized using the gas-solid reaction method in a fixed-bed reactor. The studied parameters were the influence of the synthesis temperatures (800 °C, 850 °C and 900 °C), the reaction time (90 min, 120 min, and 150 min) and the nickel concentration (5 wt%Ni, 10 wt%Ni and 15 wt%Ni) on the average crystallite size by means of a 2³ factorial experimental design based on the results obtained by XRD. These powders had their chemical and morphological characteristics evaluated using XRD, BET, SEM and EDS analyzes. The XRD analysis results show that the method was effective in obtaining WC-Ni nanostructured composite powders with good particle dispersion, desired purity, mean crystallite size ranging from 24.2 nm to 38 nm, and surface area ranging from 24.6 m2/g to 46.7 m2/g. The statistical analysis showed that the synthesis temperature variable had the greatest influence on the increase in crystallite size. Furthermore, the combination of temperature and isotherm also has a relevant effect on the response variable (crystallite size).