EFFECT OF HEATING RATE ON THERMAL-DECOMPOSITION OF LEAD DIOXIDE

Experimental data are presented on the kinetics and mechanism of PbO2 decomposition at heating rates varying from 0 to 2.5 · 103 °/sec. The studies were carried out with a time-of-flight mass spectrometer MSKH-4, a Paulik-Paulik-Erdey derivatograph and an X-ray diffractometer DRON-0.5 At low heating rates (0 to 0.2 °/s) oxygen is evolved in four stages: PbO2→ → PbO1.56→ PbO1.44→ PbO. At extremely high heating rates (2 · 102-2.5 · 103 °/s) the number of stages is reduced to two: PbO2 → PbO1.4 → PbO. An attempt is made to connect the observed change in the decomposition mechanism of PbO2 with the crystal structure formation of the lead oxides. © 1978 Wiley Heyden Ltd., Chichester and Akadémiai Kiadó, Budapest.