Thermal Behavior of Stacking Faults in Graphite Platelets

Stacking faults were observed in graphite platelets by transmission electron microscopy over the temperature range 170° to 890°K. From measurements of fault widths w at various temperatures T, it was found that (1/w)(∂w/∂T)=+(2.6±5.2)×10−4(∘K)−1. This value was used to obtain the estimate (Kbp/γ)(∂/∂T)(γ/Kbp)=−(2.6±5.2)×10−4(∘K)−1, where γ is the stacking fault energy, K the elastic coefficient of the fault, and bp the magnitude of the partial Burgers vector. The essential temperature dependence of γ in graphite is of the same order as that of K, that is, (1/γ) (∂γ/∂T)∼(1/K) (∂K/∂T).