Abstract
Sphere rotation experiments are reviewed, with emphasis on the latest results. The method and its evaluation are described in detail. The sphere rotation method has been applied so far to study the correlation between structure and energy of homo- and heterophase boundaries, also to study the relation of temperature, pressure, mobility, corrosivity, and embrittlement to the energy of grain ( = homophase) boundaries. The material specific properties, expecially the electronic structure, influence the number of low energy orientations to a great extent. All current criteria developed for the explanation of low energy boundary orientations do not fit the observations in a unique way. The common characteristics of hetero- and homophase boundaries are represented.