The spark plasma sintering (SPS) technique was employed to perform boriding of mild steel. A pack boriding method that contained a silicon carbide-boron carbide powder pack mixture was utilized in this study. The process was performed in the temperature range 700-1000 °C for 30 min. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) revealed the microstructure and phase composition of the iron boride layers (FeB and Fe2B). Plotting lnD vs. 1/T expresses concisely the boride layer's growth rate constant (D) vs. temperature (T) relation. A linear relationship between lnD and 1/T is confirmed. The kinetics of SPS boronization are discussed, and the effect of SPS on boronization is studied. The results confirmed that SPS required significantly lower activation energy for accomplishing the boriding operation. © 2002 Elsevier Science B.V. All rights reserved.