Abstract
Harper-Dorn creep is an established flow process in metals at low stresses and high temperatures. It is demonstrated that recent experimental data on single crystal and polycrystalline CaO may represent the first evidence for the occurrence of Harper-Dorn creep in non-metallic crystals. Points of agreement with the Harper-Dorn process include a linearity between creep rate and stress, a lack of dependence on grain size, the occurrence of a primary stage of creep, and an experimental transition stress marking the upper limit of Harper-Dorn creep which is in reasonable agreement with the theoretical value.