Int J Thermophys DOI 10.1007/s10765-014-1636-y Application of Non-Isothermal Thermogravimetric Method to Interpret the Decomposition Kinetics of NaNO 3 , KNO 3 , and KClO 4 H. R. Pouretedal · R. Ebadpour Received: 27 August 2013 / Accepted: 17 May 2014 © Springer Science+Business Media New York 2014 Abstract The non-isothermal thermogravimetric method was used to study the ther- mal decomposition of KClO 4 , KNO 3 , and NaNO 3 at heating rates of (5, 10, 15, and 20) K· min −1 . The activation energy of thermal decomposition reactions was computed by isoconversional methods of Ozawa–Flynn–Wall, Kissinger–Akahiro–Sunose, and Friedman equations. Also, the kinetic triplet of the thermal decomposition of salts was determined by the model-fitting method of the modified Coats–Redfern equation. The activation energies of KClO 4 , KNO 3 , and NaNO 3 of (293 to 307, 160 to 209, and 192 to 245) kJ · mol −1 , respectively, are obtained by non–isothermal isoconversional methods. The modified Coats and Redfern method showed that the most probable mechanism functions g(α) of [−ln(1 − α)] 1/3 (model A3: Arami–Erofeev equation) and (1 − α) −1 − 1 (model F2: second order) can be used to predict the decomposition mechanisms of KClO 4 , KNO 3 , and NaNO 3 , respectively. Keywords Activation energy · KClO 4 · Kinetic · KNO 3 · NaNO 3 · Thermogravimetry 1 Introduction Potassium perchlorate (KClO 4 ), potassium nitrate (KNO 3 ), and sodium nitrate (NaNO 3 ) have gained importance as oxidizers in energetic materials such as solid composite propellants and pyrotechnics [1]. Like other perchlorates, potassium per- chlorate salt is a strong oxidizer and potentially reacts with many organic substances. A crystalline solid of KClO 4 is a common oxidizer that used in fireworks, ammu- H. R. Pouretedal (B) · R. Ebadpour Department of Applied Chemistry, Maleke-ashtar University of Technology, Esfah ¯ an, Islamic Republic of Iran e-mail: hr_pouretedal@mut-es.ac.ir 123