Cr and Ni were originally incorporated as alloying elements in stainless steel as mentioned in the experimental procedure section. It could be noticed that there was also a Si peak detected in the sample. This element was not originally contained in the starting stainless steel powder and thus should not be seen in the as- synthesized powders as well. The appearance of Si could be the result of impacting of X-ray on a solid state SiLi detector which inadvertently knocked out Si K-shell electrons in the detector and reduced X-ray's energy measured in the detector by the Si absorption edge energy (~1.74 keV). Moreover, wall-induced contamination from quartz tube was also a possible cause since this was the only the part that was involved with Si-containing material during synthesis of SS/CNT composite particles.