Electrochemical Characterizations of Ni/Doped Lanthanum Silicates Cermets Deposited by Spin Coating

In this study, anodic cermets nickel/apatite were elaborated and deposited by spin-coating on dense pellets of the apatite electrolyte La9Sr1Si6O26+δ (δ ≈ 0.5). The sintering characteristics and microstructural properties of this cermet were investigated. The influence of the slurries compositions, of the spin-coating conditions and of the sintering temperatures on the deposit properties was studied. The particle sizes of NiO and of apatite material were respectively 300 nm and 1 μm as shown on the SEM micrographs. This difference in particle size resulted in different sintering rates and could explain the lack of adherence of the deposits after reduction of NiO. Agglomeration of the NiO particles occurred above a sintering temperature of 1,200 °C. This result was corroborated by impedance spectroscopy. The highest resistance was measured for the sample sintered at 1,200 °C.