HREM investigations of intermediate ZnO and ZnO/Y-ZrO2 layers in Y-ZrO2 bicrystals and ZnO films grown on Y-ZrO2 bicrystal substrates

The structure of yttrium-stabilized ZrO2 (YSZ) bicrystals with ZnO and ZnO/ YSZ/ZnO/YSZ/ZnO intermediate layers, as well as ZnO films grown on YSZ bicr ystal (110)/90 degrees substrates, has been investigated by means of high-r esolution electron microscopy (HREM) and microanalysis. All bicrystals were produced by the solid-phase intergrowth (SPI) method. The internal ZnO fil m in the bicrystal formed at the SPI temperature of 1400 degreesC consisted of domains with two symmetrical orientations: [1 (1) over bar0](YSZ) //[01 0](Zno),[001](YSZ) //[63 (2) over bar](ZnO) and [1 (1) over bar0](YSZ)//[01 0](ZnO), [011](YSZ)//[(6) over bar(3) over bar2]ZnO. A bicrystal with a ZnO /YSZ/ZnO/YSZ/ZnO internal film was formed at the temperature of 1200 degree sC. There was no mixing of ZnO and YSZ films and no traces of any solid-pha se reactions were observed. Grains in all internal ZnO fims and ZnO films g rown on the bicrystal substrates had numerous stacking faults. It was found that SPI does not influence the density and structure of these defects. Or ientational relationships between YSZ and ZnO in all samples were determine d. The ZnO films grown on (110)/90 degrees bicrystal substrates inherited t he grain boundary (GB) from the substrate. Its structure and geometry is de termined by four variants of ZnO grain growth. (C) 2000 Published by Elsevi er Science B.V.