Mechanical Properties of Strontium-Doped Lanthanum Manganite

Solid oxide fuel cells that incorporate stabilized-zirconia electrolytes commonly use the transition-metal oxide perovskite La_0.875Sr_0.125MnO_3+δ as the cathode. While in operation, the cathode can be subjected to significant stresses, because of thermal expansion mismatch between mating components. The mechanical behavior of La_0.875Sr_0.125MnO_3+δ has been studied using three-point bend strength measurements at ambient, 400°C, 800°C and 1000°C. The results show that phase transformations have an important role in the mechanical-strength behavior. The results also indicate some unique strengthening effects that are associated with the evolution of the unit cell with temperature and the increasing symmetry of the crystal lattice.