Abrasive and Erosive Wear Performance of Rare Earth Oxide Doped Ni/WC Coatings

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Surajit Purkayastha ◽  
D. K. Dwivedi
Keyword(s):  
Rare Earth ◽  
Erosive Wear ◽  
Rare Earth Oxide ◽  
Wear Performance ◽  
Ceramic Phase ◽  
Enhanced Dissolution ◽  
Impact Angles ◽  
Rare Earth Doped ◽  
Microstructural Examination ◽  
Nickel Tungsten

The effect of CeO2 modification on flame sprayed nickel-tungsten carbide (WC) coatings was investigated. The modified coatings exhibited smaller grain sizes of the ceramic phase due to enhanced dissolution of the WC phase. The rare earth doped coatings, especially Ni-WC +0.9% wt. CeO2, showed superior abrasive wear resistance with respect to the unmodified coating mainly due to enhanced hardness. Coating modified with 0.6% wt. CeO2 demonstrated superior erosion resistance at both impact angles, 30 deg and 90 deg, respectively, primarily due to low porosity levels. Microstructural examination showed different wear mechanisms in conventional and doped coatings.

Microstructure and Mechanical Properties of Rare-Earth Doped Si3N4 and Si3N4/SiC Ceramics

2010 ◽  
Vol 65 ◽  
pp. 78-85 ◽  
Author(s):  
Peter Tatarko ◽  
Štefánia Lojanová ◽  
Zdeněk Chlup ◽  
Ján Dusza ◽  
Pavol Šajgalík
Keyword(s):  
Mechanical Properties ◽  
Rare Earth ◽  
Aspect Ratio ◽  
Ionic Radius ◽  
Earth Element ◽  
Rare Earth Oxide ◽  
Sic Ceramics ◽  
Microstructure And Mechanical Properties ◽  
Significant Difference ◽  
Rare Earth Doped

Microstructure and mechanical properties of Si3N4 and Si3N4 + SiC nanocomposites sintered with rare-earth oxide additives (La2O3, Y2O3, Yb2O3 and Lu2O3) have been investigated. The composites exhibited smaller grain diameter compared to that of monolithic materials. The aspect ratio of β-Si3N4 grains increased with a decreasing ionic radius of rare-earth elements in the Si3N4 monoliths as well as in the Si3N4-SiC nanocomposites. The hardness of both systems increased with a decreasing ionic radius of rare-earth element. The fracture toughness of the materials with coarser microstructure and higher aspect ratio was higher due to the more frequent toughening mechanisms. No significant difference between strength values of monoliths and composites was observed and the strength in the composites was determined mainly by the present processing flaws. Significantly improved creep resistance was observed in the case of composites and for materials with smaller ionic radius of RE3+.

Development of SiAlON - From Mechanical to Optical Applications

2007 ◽  
Vol 352 ◽  
pp. 173-178 ◽  
Author(s):  
Tetsuo Yamada ◽  
Takeshi Yamao ◽  
Shinichi Sakata
Keyword(s):  
Rare Earth ◽  
Ionic Radius ◽  
Bending Strength ◽  
Yttrium Aluminum Garnet ◽  
Functional Materials ◽  
Rare Earth Oxide ◽  
Rare Earth Ions ◽  
High Temperature Strength ◽  
Diverse Range ◽  
Rare Earth Doped

Various rare-earth-doped α-SiAlON powders with high purity were prepared to study mechanical and optical properties of SiAlON-based functional materials in connection with ionic radius and electronic structure of rare-earth elements. Single phase rare-earth-doped α-SiAlON powders were obtained at a temperature as low as 1873 K by heating powder mixtures of rare-earth oxide, AlN and highly active ultrafine amorphous Si3N4. Bending strength of highly dense rare-earth-doped α/β-SiAlON-based ceramics was increased with decreasing radii of rare-earth ions, i.e., Yb-SiAlON-based ceramics exhibited excellent high-temperature strength and oxidation resistance caused by the small ionic radius of ytterbium. As for optical application, α-SiAlON is an excellent host lattice with good thermal and chemical stability for doping rare-earth element which activates photoluminescence. Europium-doped Ca-α-SiAlON phosphor formulated as CaxEuy(Si,Al)12(O,N)16 (where 0<x+y<2) was prepared to obtain high quality phosphor with high brightness and desired emission characteristics. Photoluminescence spectra of the resultant Europium-doped Ca-α-SiAlON exhibited high emission intensity at peak wavelength of 580-600 nm giving the better yellow color tone than Cerium-doped yttrium aluminum garnet for applying white LED. It was demonstrated that nitrides or oxynitrides were the innovative materials for the diverse range of high performance specialty applications.

Waveguide amplifiers in rare-earth doped glasses : fabrication, characterisation [MATH] modelling

1994 ◽  
Vol 04 (C4) ◽  
pp. C4-277-C4-280 ◽  
Author(s):  
B. HYDE ◽  
D. BARBIER ◽  
J. HUBNER ◽  
J.-M. JOUANNO ◽  
A. KEVORKIAN ◽  
...  
Keyword(s):  
Rare Earth ◽  
Waveguide Amplifiers ◽  
Doped Glasses ◽  
Rare Earth Doped

SYNTHESIS AND PHOTOLUMINESCENCE STUDIES OF RARE EARTH DOPED [1.5%] CaO

2019 ◽  
Vol 7 (3) ◽  
pp. 37
Author(s):  
JITESH CHANDRAPAL SHARMA ◽  
K. SURESH ◽  
Y. H. GANDHI ◽  
K. V. R. MURTHY ◽  
◽  
...  
Keyword(s):  
Rare Earth ◽  
Photoluminescence Studies ◽  
Rare Earth Doped

Improving VCSEL's & Rare-Earth-Doped Led's.

1998 ◽  
Author(s):  
hyatt M. Gibbs ◽  
Galina Khitrova
Keyword(s):  
Rare Earth ◽  
Rare Earth Doped

Enhanced electron correlation in rare-earth doped Ca3Co4O9

2010 ◽  
Vol 97 (6) ◽  
pp. 062114 ◽  
Author(s):  
Yang Wang ◽  
Luxiang Xu ◽  
Yu Sui ◽  
Xianjie Wang ◽  
Jinguang Cheng ◽  
...  
Keyword(s):  
Rare Earth ◽  
Electron Correlation ◽  
Rare Earth Doped
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