DO DISLOCATIONS AND STACKING-FAULTS INCREASE THE OXIDATION RATE OF PYRITES

XPS, SEM, and TEM studies were made on coal, non-coal, and shock-loade d pyrites that had been experimentally weathered under high relative h umidity. Reactivity (oxidation) of the different pyrite samples may be related to their stacking fault densities. A coal pyrite sample that had the highest stacking fault concentration was also the most reactiv e pyrite. No systematic relationship between reactivity and dislocatio n density was observed. Shock-loaded samples exposed to mean bulk shoc k temperatures between 175 and 475 degrees C showed an increase in the number of reactive sites and shock-loaded samples exposed to mean bul k shock temperatures between 500 and 700 degrees C showed decreases in the number of reactive sites.