Excess Zn in powder and in ceramic ZnO is investigated by the atomic absorption photometry (AAP) method. All the ZnO samples tested were previously heat treated at temperature 900 degreesC and at fixed Zn pressures from 0.1 to 0.6 of saturated p(Zn) at given treatment temperature. The vapour-crystal equilibrium in ZnO:Zn crystal was established in 20-40 min. To determine the excess zinc in ZnO :samples. the AAP of zinc vapour was used in the conditions of solid-vapour equilibrium. Optical absorbance of zinc. proportional to the concentration of zinc atoms in the vapour phase, was registered photoelectrically on the Zn resonance line. The analysis of temperature dependence of zinc pressure indicated that the value of zinc excess lies in the concentration interval of 10(18)-10(19) cm(-3) and depends on the sample biography and the conditions of preliminary heat treatment. Zn adsorption on powder ZnO grain surfaces and the reactions of impurity metals with excess Zn in ZnO ceramics were observed in Zn AAP experiments. (C) 2004 Elsevier B.V. All rights reserved.