Role of rare earth oxide particles on the oxidation behaviour of silicon carbide coated 2.5D carbon fibre preforms

The calcium phosphate bioceramic coating was fabricated on titanium alloy (Ti-6Al-4V) substrate by a 5kW continuous transverse flow CO2 laser. Due to the peculiar role of rare earth oxide in laser cladding, the effect of ceria additive on the microstructure and properties of laser-cladded bioceramic coating was investigated by means of scanning electron microscope (SEM), X-ray diffraction (XRD), microhardness and corrosion resistance testing. The results indicate that the appearance of rare earth oxide ceria in the precursor powders has an impact on the microstructure and properties of the laser-cladded bioceramic coating. Calcium phosphate bioceramic such as hydroxyapatite (HA) and β-tricalcium phosphate (β-TCP) are synthesized on the top surface of laser-cladded specimens. And the addition of rare earth oxide ceria in pre-placed powders has an influence on the formation of calcium phosphate bioceramic phases. Furthermore, it reveals that the laser-cladded bioceramic coating of ceria additive in pre-placed powders has more favorable microhardness and corrosion resistance compared with the coating without rare earth oxide.

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Characterization of crystalline rare-earth oxide high-K dielectrics grown by molecular beam epitaxy on silicon carbide

Journal of Vacuum Science & Technology B Microelectronics and Nanometer Structures Processing Measurement and Phenomena ◽

10.1116/1.2214702 ◽

2006 ◽

Vol 24 (4) ◽

pp. 2115 ◽

Cited By ~ 25

Author(s):

A. Fissel ◽

M. Czernohorsky ◽

H. J. Osten

Keyword(s):

Silicon Carbide ◽

Rare Earth ◽

Molecular Beam Epitaxy ◽

Molecular Beam ◽

Rare Earth Oxide ◽

High K

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Effects of rare-earth oxide and alumina additives on thermal conductivity of liquid-phase-sintered silicon carbide

Journal of Materials Research ◽

10.1557/jmr.2003.0259 ◽

2003 ◽

Vol 18 (8) ◽

pp. 1854-1862 ◽

Cited By ~ 41

Author(s):

You Zhou ◽

Kiyoshi Hirao ◽

Yukihiko Yamauchi ◽

Shuzo Kanzaki

Keyword(s):

Thermal Conductivity ◽

Silicon Carbide ◽

Rare Earth ◽

Liquid Phase ◽

Point Defects ◽

Rare Earth Oxide ◽

Low Oxygen ◽

Sic Ceramics ◽

Sintered Silicon ◽

Thermal Conductivities

SiC ceramics were prepared from a β–SiC powder doped with two different sintering additives—a mixture of La2O3and Y2O3and a mixture of Al2O3and Y2O3—by hot pressing and annealing. Their microstructures, phase compositions, lattice oxygen contents, and thermal conductivities were evaluated. The SiC doped with rare-earth oxides attained thermal conductivities in excess of 200 W/(m K); however, the SiC doped with additives containing alumina had thermal conductivities lower than 71 W/(m K). The high thermal conductivity of the rare-earth-oxide-doped SiC was attributed to the low oxygen content in SiC lattice, high SiC–SiC contiguity, and lack of β– to α–SiC polytypic transformation. The low thermal conductivity of the alumina-doped SiC was attributed to the point defects resulting from the dissolution of Al2O3into SiC lattice and the occurrence of polytypic transformation.

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