Student Author: Jay Zeck (Class of 2005)
Faculty Author: Dr. Ali Bakhshai
The mixing of reactant powders by the process of ball-milling is able to induce a mechanochemical reaction. The progression of such a reaction is thought to be governed by a Self Heat-Propagating Synthesis (SHS) process, whereas the ignition time of the powders directly relates to powder mass. Literature previously reported by our group noted that the reductive milling of Cu2O and Al or Ti deviated from this monotonic trend distinctive of SHS. Exponential decay was observed in the Cu2O low masses and suggested an alternative process was at work. To clarify whether the ignition behavior of Cu2O was anomalistic or was overall significant to milling reactivity, a systematic investigation of compounds similar to the copper oxide system was conducted. The compounds explored were non-oxide copper compounds as well as oxide systems containing metals with similar physical and chemical properties to copper (CuS, Cu2S, CuO, Ag2O, Bi2O3, PbO). The systematic studies of ignition trends for each of these systems in addition to X-ray diffraction measurements and surface morphology by an Atomic Force Microscope-all point convincingly to the occurrence of an alternative, non-layer based, process of ignition.
Click here for a Powerpoint presentation of Jay's talk.