Fracture In Polycrystalline Iridium Coating.

Iridium coating was prepared by the double glow plasma. The phase identification and the microstructure observation of the fracture surface of the coating were examined by X-ray diffraction and scanning electron microscopy, respectively. The deposition rate of the coating was up to 20µm/h. The iridium coating failed predominantly by grain boundary brittle fracture at room temperatures. Brittle intergranular fracture does not depend on grain size. Intergranular fracture in iridium coating has been considered to arise from low cohesive strength of the grain boundaries. [ABSTRACT FROM AUTHOR]