For the GZ and GZ ndash YSZ composite coatings during

3. Results and discussion
Fig. 1. XRD pattern of the as-synthesized GZ powder.Figure optionsDownload full-size imageDownload as PowerPoint slide
Fig. 2. Morphology (a) and particle size distribution (b) of the spray dried GZ–YSZ powder for UMI-77 spraying.Figure optionsDownload full-size imageDownload as PowerPoint slide
Fig. 3. XRD patterns of the as-prepared GZ powder (a) and as-sprayed GZ–YSZ coating (b).Figure optionsDownload full-size imageDownload as PowerPoint slide
The microstructures of the fracture surfaces of the densified GZ and GZ–YSZ composite are shown in Fig. 4. The fracture type of the GZ is macronutrients found to be intergranular, while the GZ–YSZ composite exhibits a mixture of transgranular and intergranular fracture. Meanwhile, the average grain size of GZ and GZ–YSZ composite evaluated from SEM images is about 0.8 μm and 0.5 μm, respectively. The grain size of the GZ–YSZ composite decreases significantly with the addition of YSZ particles, which could be attributed to the YSZ particles dispersed in the GZ matrix restrict the grain boundary motion and limit the grain growth of the GZ matrix during the HPS process.