The aim of this study is to specify an optimal method for coating LSM layer on a YSZ substrate. Initially the prepared powders were validated by X-Ray Diffraction (XRD) technique. A mixture of NiO-YSZ (50:50 wt%) powders were created by mechanical milling method; then the mix was prepressed in a disk shape die as the base substrate; after that, YSZ powder was added on the substrate and they were pressed and sintered at 1450°C for 3 hours. Three different methods including dip coating, spraying, and brush painting using various concentrations of LSM suspensions, were applied on the obtained substrate. Then, LSM coated disks were sintered at 1250°C for 2 hours. The coating surface and the cross section of the as-sintered disks which were investigated and scanned by an electron microscope (SEM), illustrated a uniform coating in dip-coated samples; also, another advantage of this method was the negligible agglomeration of the LSM layer. Moreover, the linear EDS elemental analysis from the surface of the layer -which is coating the substrate-indicated the desired results for the coating which was fabricated by the dip coating method. K E Y W O R D S

In this study, NiO–yttria stabilized zirconia (YSZ) composite anodes were prepared by using ball-milling followed by a sintering process. For this purpose, two different weight percent ratios of NiO and YSZ powders (50 : 50 and 60 : 40) were mixed by the cost-effective ball-milling method. The morphology and particle size distribution of the mixed powders were investigated using scanning electron microscopy and dynamic light scattering methods, respectively. The powders were then uniaxially pressed to form pellets with a thickness and diameter of around 1 and 22 mm, respectively. Sintering of the pellets was conducted at 1 100 °C and the microstructure and porosity, as well as phase analysis of bulk composites, were then investigated using scanning electron microscopy and X-ray diffraction, respectively. More importantly, the microhardnesses of the prepared pellets were obtained and compared with literature values to evaluate the accuracy of the sintering process. The results showed that the open porosity of the samples varied between 30 to 40 percent, which makes them suitable for anode application in solid oxide fuel cells. The prepared NiO–YSZ composites with a uniform distribution of Ni particles showed a value of microhardness above 0.5 GPa, and these results were discussed in detail.