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Characterization of a Functionally Gradient Ceramic Based on CaZrO3 – MgO
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Resumo(s)
In the case, where the structure is exposed to severe conditions of operation, such as high strength, wear
and high-temperature gradients (e.g. engine components, insulation system, thermal barrier and thermal
shield) must be applied.
In this work, it was developed and characterized a functional gradient ceramic coating. A ceramic
composite based in CaZrO3 – MgO was used in order to design a material with successive layers of
molar composition 2:3, 1:1 and 1:3 of CaZrO3:MgO, respectively. A dense material was obtained by
sintering assisted reaction (Figure 1). Thermal conductivity at room temperature, hardness, fracture
toughness, surface energy, and microstructure were characterized.The results show for monolithic specimens of 2:3 CZ, 1:1 CZ and 1:3 CZ a H of 9,9 GPa, 9,8 GPa and
10,1GPa; a Kc of 1,6 MPa.m1/2, 1,7 MPa.m1/ and 2,1 MPa.m1/2; a k of 0,59 W/mK; 0,76 W/mK and 0,79
W/mK; and a surface energy (SE) of 43,27 mN/m, 51,39 mN/m and 46,55 mN/m, respectively. The
functional gradient ceramic shows a H of 10,7 GPa, a Kc of 1,97 MPa.m1/2; a k of 0,82 W/mK and SE of
53,98 mN/m. The individual composition and the functional gradient ceramic show a similar relative
density of 4,3 g/cm3 and a porosity of 0,2%. This design methodology has the advantage of allowing the
properties of the same material to suit different substrates.
Descrição
Palavras-chave
Functionally Gradient Ceramic Ceramic multiphasic composites Calcium zirconate (CaZrO3) Magnesium oxide (MgO) Ceramic coating Thermal conductivity Microstructure Vickers hardness Surface energy Fracture toughness Porosity