Page - 172 - in Advanced Chemical Kinetics

For typical systems, the points of differing heat release characteristics can be due to phase transitions, crystallization, or reactions; however, this sectionwill only focusonSHS-reaction kinetics. In order to determine the reaction kinetics, the experiment is conducted multiple timeswithdifferent heating rates. The classicalmethod fordetermining the reactionkinetics, specifically the activation energy, is by use of the Kissinger method [27], however, many alternativemethods for data analysis have been suggested and arewidely utilized [28–34]. Theactivationenergy,Ea,canbecomputedbyplottingln(β/Tp 2)asafunctionof1/Tp,whereTp is thepeak temperature (Figure2). TheDTA/DSCbasedmethodsarethemostwidelyusedforgaslessSHSsystems,withmultiple studies into intermetallics, specifically theNi/Al [35–43], Ti/Al [44–46],Co/Al [47],Al/Ru [48], Nb/Al [49], andMg/Al [50] systems, in addition toother binary solid-solid compositions, i.e., the Si/C [51],Mo/Si [52], Zr/B [53], Fe/Se [54].More complicated ternary systemswere also investigated [54–61]. Ingeneral, awidevarietyof factors can influence themeasuredkinetics, includingvariations in reactantmicrostructure, heating rates, amongother factors.Although thereareanumberof studies into the samesystems, itwouldbevaluable for systematicwork tobe conductedwhere these factors are studied indepthacrossdifferent systems to seewhat Figure2. Summaryofdatacollectedusing isothermalkineticanalysismethods. Advanced Chemical Kinetics172