Preparation of Dense Platinum-Yttria Stabilized Zirconia and Yttria Stabilized Zirconia Films on Porous La0.9Sr0.1MnO3 (LSM) Substrates

A sol–gel process has been developed to prepare fine powder of La_0.9Sr_0.1MnO₃ (LSM) with an average particle size ∼40 nm. The LSM powder is pressed to pellets, on which a uniform green yttria-stabilized zirconia (YSZ) film is deposited using an electrophoretic deposition process. A green composite film of platinum and YSZ (Pt-YSZ) is prepared on the top of the green YSZ film using a colloidal process, followed by filling the pores using a sol–gel process. The three-layered structure, a green Pt-YSZ film, and a green YSZ film on a green LSM substrate, is fired at 1250°C for 3 h, resulting in a dense Pt-YSZ and YSZ film supported by a porous LSM substrate. Electrical measurements show that the sensors with the three-layered structure display a well-defined diffusion-limited current in gases containing partial pressure of oxygen up to ∼9 vol%, implying that the quality of the Pt-YSZ and YSZ film is adequate for the sensor application.