Ceramic materials were investigated as thermal barrier coatings and electrolytes. Electrophoretic deposition（EPD） and physical vapor deposition（PVD） were employed to fabricate samples, and the mechanical propertie...Ceramic materials were investigated as thermal barrier coatings and electrolytes. Electrophoretic deposition（EPD） and physical vapor deposition（PVD） were employed to fabricate samples, and the mechanical properties and microstructure were examined by nanoindentation and microscopy, respectively. Yttria-stabilized zirconia/alumina（YSZ/Al2O3） composite coatings, a candidate for thermal barrier coatings, yield a kinky, rather than smooth, load–displacement curve. Scanning electron microscope（SEM） examination reveals that the kinky curve is because of the porous microstructure and cracks are caused by the compression of the indenter. Li0.34La0.51 Ti O2.94（LLTO） on Si/Sr Ru O3（Si/SRO） substrates, an ionic conductor in nature, demonstrates electronic performance. Although SEM images show a continuous and smooth microstructure, a close examination of the microstructure by transmission electron microscopy（TEM） reveals that the observed spikes indicate electronic performance. Therefore, we can conclude that ceramic coatings could serve multiple purposes but their properties are microstructure-dependent.展开更多
The Cr-/Si-modified Ni Al Hf coatings were produced on single-crystal（SC） superalloy N5 by electron beam physical vapor deposition（EB-PVD）. The cyclic oxidation behavior of the coatings at 1100 °C was investi...The Cr-/Si-modified Ni Al Hf coatings were produced on single-crystal（SC） superalloy N5 by electron beam physical vapor deposition（EB-PVD）. The cyclic oxidation behavior of the coatings at 1100 °C was investigated. The microstructures of the oxide scales grown on the coatings were characterized by scanning electron microscope（SEM） with energy-dispersive X-ray spectrum（EDX）,electron probe micro-analyzer（EPMA） and X-ray diffraction（XRD）. The effects of Cr and Si on the cyclic oxidation behavior of the Ni Al Hf coatings were discussed. The addition of Si to the Ni Al Hf Cr coating not only reduces the oxidation rate but also enhances the oxide scale adherence.Owing to the addition of Si in the coating, the segregation of Cr and Mo beneath the oxide scale is effectively avoided,which contributes to enhancing oxide scale adherence.展开更多
基金financially supported by the Natural Science Foundation of Hebei Province,China(No.E2013502272)
文摘Ceramic materials were investigated as thermal barrier coatings and electrolytes. Electrophoretic deposition（EPD） and physical vapor deposition（PVD） were employed to fabricate samples, and the mechanical properties and microstructure were examined by nanoindentation and microscopy, respectively. Yttria-stabilized zirconia/alumina（YSZ/Al2O3） composite coatings, a candidate for thermal barrier coatings, yield a kinky, rather than smooth, load–displacement curve. Scanning electron microscope（SEM） examination reveals that the kinky curve is because of the porous microstructure and cracks are caused by the compression of the indenter. Li0.34La0.51 Ti O2.94（LLTO） on Si/Sr Ru O3（Si/SRO） substrates, an ionic conductor in nature, demonstrates electronic performance. Although SEM images show a continuous and smooth microstructure, a close examination of the microstructure by transmission electron microscopy（TEM） reveals that the observed spikes indicate electronic performance. Therefore, we can conclude that ceramic coatings could serve multiple purposes but their properties are microstructure-dependent.
基金financially supported by the National Basic Research Program of China (Nos. 2012CB625100 and 2010CB631200)the National Natural Science Foundation of China (No. 51231001)
文摘The Cr-/Si-modified Ni Al Hf coatings were produced on single-crystal（SC） superalloy N5 by electron beam physical vapor deposition（EB-PVD）. The cyclic oxidation behavior of the coatings at 1100 °C was investigated. The microstructures of the oxide scales grown on the coatings were characterized by scanning electron microscope（SEM） with energy-dispersive X-ray spectrum（EDX）,electron probe micro-analyzer（EPMA） and X-ray diffraction（XRD）. The effects of Cr and Si on the cyclic oxidation behavior of the Ni Al Hf coatings were discussed. The addition of Si to the Ni Al Hf Cr coating not only reduces the oxidation rate but also enhances the oxide scale adherence.Owing to the addition of Si in the coating, the segregation of Cr and Mo beneath the oxide scale is effectively avoided,which contributes to enhancing oxide scale adherence.
