Thermal shock resistance and mechanical properties of La2Ce2O7 thermal barrier coatings with segmented structure

La2Ce2O7 (LCO) is a promising candidate material for thermal barrier coatings (TBCs) application because of its higher temperature capability and better thermal insulation property relative to yttria stabilized zirconia (YSZ). In this work, La2Ce2O7 TBC with segmentation crack structure was produced by atmospheric plasma spray (APS). The mechanical properties of the sprayed coatings at room temperature including microhardness, Young's modulus, fracture toughness and tensile strength were evaluated. The Young's modulus and microhardness of the segmented coating were measured to be about 25 and 5 GPa, relatively higher than those of the non-segmented coating, respectively. The fracture toughness of the LCO coating is in a range of 1.3-1.5 MPa m(1/2) about 40% lower than that of the YSZ coating. The segmented TBC had a lifetime of more than 700 cycles, improving the lifetime by nearly two times as compared to the non-segmented TBC. The failure of the segmented coating occurred by chipping spallation and delamination cracking within the coating. (C) 2009 Elsevier Ltd and Techna Group S.r.l. All rights reserved.