Accession Number : ADA599516


Title :   Multiphase-Multifunctional Ceramic Coatings


Descriptive Note : Final rept. 3 Jun 2010-3 Jun 2013


Corporate Author : CENTRO DE INVESTIGACION EN MATERIALES AVANZADOS S C CHIH (MEXICO)


Personal Author(s) : Trapaga-Martinez, Luis G ; Levi, Carlos G


Full Text : https://apps.dtic.mil/dtic/tr/fulltext/u2/a599516.pdf


Report Date : 30 Jun 2013


Pagination or Media Count : 19


Abstract : This project deals with ceramic coatings deposited by thermal spray and based on La2Zr2O7 (LZO) + toughening phase. The phase that showed promising results in dense ceramics to be scaled up and prepare coatings is the LaAlO3 (LAO). LZO and LAO mixtures in a 70:30 mol% ratio were deposited on SS304 and FeCrAlY substrates. Milling followed by a spray drying process enabled production of 70LZO:30LAO mixture in the form of spherical agglomerates with adequate size distribution and flow properties for feeding into a thermal-spray system. The as-sprayed coating comprises crystalline LZO and partially amorphous LAO. The amorphous phase resulted from the high cooling rate experienced by the molten particles. The coatings were annealed at 1100 deg C for promoting crystallization of the amorphous phase. The elastic modulus and hardness clearly increased after the annealing treatment. However, the fracture toughness tested on the annealed coating showed low values of 1.04 MPa m. Further research is required to mitigate the formation of amorphous LAO by proper control of the quenching conditions. Although the fracture toughness improves moderately as the LaAlO3 fraction increases in dense ceramics, the values are still lower than those considered acceptable.


Descriptors :   *CERAMIC COATINGS , *MECHANICAL PROPERTIES , DEPOSITION , HIGH TEMPERATURE , MICROSTRUCTURE , PEROVSKITES , PHASE , POWDERS , RARE EARTH COMPOUNDS , SOLID SOLUTIONS , SPRAYS , SYNTHESIS(CHEMISTRY) , THERMAL STABILITY , ZIRCONATES


Subject Categories : Coatings, Colorants and Finishes
      Mechanics


Distribution Statement : APPROVED FOR PUBLIC RELEASE