Piezoelectric thin films of PbZrxTi1-xO3 (PZT) on membranes are the subject of keen interest for the fabrication of micro-sensors and actuators. Piezoelectric activity of the PZT on Si-based membranes has been shown, and a micromotor has been demonstrated. Standard substrates are based on Si due to the good barrier properties of SiO2 and Si3N4 layers, which protect the Si against further oxidation. For some applications, however, such structures are not appropriate. For instance, thin metallic sheets, which are more robust and do not need micromachining, should be better substrates for actuator and motor applications. Direct deposition of PZT on common metals or Si is not possible. Metals degrade readily during the high temperatures and oxidising conditions needed to deposit PZT. Additionally, they can interdiffuse with the PZT and alter its properties. Hence, suitable barriers are needed, which can also work as bottom electrodes for the PZT. In this work, we have characerised a functioning metal-barrier-PZT structure by transmission electron microscopy. The extent of metal, oxygen and lead diffusion was assessed by nanoprobe measurments. A slight, acceptable metal diffusion into the PZT layer has been found, as well as some oxidation at the metal-barrier interface