Abstract
The paper describes the requirements to which ZnO evaporates without being fractured while laser is radiated. The fracturing phenomenon is mechanically evaluated. By executing a laser radiation test, the influence of relative densities on the fracture are investigated. It is shown that ZnO sintered billet with the relative density from 0.6 to 0.8 evaporates without being fractured while the laser is radiated. The billet was sintered by hot press. The sintering condition to obtain the ZnO sintering billet with the relative density from 0.6 to 0.8 is restricted within a range of 850°C to 1000°C under the sintering pressure 10MPa. The condition is restricted within a range of 800°C to 900°C under sintering press 15Mpa, whereas that is 800°C under sintering press 20MPa. Microscopic thermal stress and fracture stress appearing in peripheries of the porosity in the sintering billet were calculated by the homogenization method. Since the fracture stress is lower than the thermal stress of billet less than approximately 0.8 of the relative density, the produced billet is not fractured while laser is radiated.
