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Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.3/41713
- Effects of pores on mechanical properties of plasma-sprayed ceramic coatings
- Nakamura, Toshio; Qian, G.; Berndt, C. C.
- The effects of pore sizes, shapes, and orientations on the mechanical properties of thermally sprayed ceramic coatings are investigated. The analysis is conducted using detailed finite-element models with geometries similar to those of actual ceramic coatings containing many embedded pores. These microstructural models include many randomly placed pores of different sizes and shapes and are loaded in tension to determine their effective elastic moduli along the spray and transverse directions. We modeled coatings with statistical distributions of pore sizes and shapes that followed those of actual Al2O3-TiO2 coatings. Because the pores in such a model are of different sizes and shapes, the model must be large enough to contain sufficient pores before the average modulus obtained from uniaxial loading can be identified as an effective property. Using differently sized models, we determined the variability of the average moduli. Such information is valuable when homogenized or continuum material models are used in the stress analyses of coatings. Our computed results show that a model must be large enough to contain 50-100 pores before the averaging of properties is accurate. Using the Al2O3-TiO2 models, we also simulated microindentation tests. Unlike the results determined from uniaxial loading, the elastic moduli estimated from indentation possessed large variations. Apparently, the morphology of the pores immediately beneath the indentation or within the zone of influence has a significant effect on the response of the indenter and the measured modulus. The implications of these results and the computational capability to predict the mechanical properties of porous, plasma-sprayed ceramic coatings are discussed here.
- Publication type
- Journal article
- Journal of the American Ceramic Society, Vol. 83, no. 3 (Mar 2000), pp. 578-584
- Publication year
- Alumina; Ceramic coatings; Elastic moduli; Finite element method; Mathematical models; Microstructural models; Microstructure; Plasma spraying; Pore size; Sprayed coatings; Statistical methods; Stress analysis; Tensile testing; Titanium dioxide
- Wiley-Blackwell Publishing
- Publisher URL
- Additional information
- Supported by the Center for Thermal Spray Research at Stony Brook, under Grant No. NSF-MRSEC DMR632570.
- Peer reviewed