Page - 180 - in Advanced Chemical Kinetics

However,whentheyincreasedtheheatingrate, theyinsteadonlywitnessedasinglepeak.This peak was related to the solid state transition to the final product. For transitional values between the twoextremes, they found that therewere relative contributions of bothdifferent mechanisms.This is an importantobservationwhichshouldbeaccountedwhen investigating thereactionkinetics inhighlyexothermicsystems. Indeed, it showsthat it ispossible tocontrol the reactionmechanism depending on the applied experimental conditions. This effect was confirmedbymanyresearchersboth forgaslessandgas-solid systems [36, 56, 158–162]and is illustrated in Figure 8. Furthermore, depending on the reactionmechanism, it is possible to controlboth the finalproductphasesandtheirmicrostructures, thusproducingmaterialswith tailoredproperties. 10.TheNi/Alsystemasamodel forSHSkinetics In theSHScommunity, theNi/Al systemhasbeenwidelyusedamodel system. Itwaschosen because of its low ignition temperature, high oxidation resistance, and ease of processing. Because of this, all of the abovementioned techniques havebeenutilized to studykinetics in Figure 8. DTA-TG curves for the PTFE-Al2O3 systemusing heating rates of (a) 20, (b) 80, (c) 150, and (d) 160 Cmin 1 under an argon atmosphere. The additional lines are showing the changes in heat flow andmass percentage values. Adapted fromHobosyanetal. [56]. Advanced Chemical Kinetics180