Reference

Effects of rare earth dopants on grain boundary bonding in alumina-silicon carbide composites

Effects of rare earth dopants on grain boundary bonding in alumina-silicon carbide composites. Deng, Zhen-yan; Zhou, You; Brito, Manuel E.; Tanaka, Yoshihisa; Ohji, Tatsuki (Metal Matrix Composite Research Group, National Institute for Materials Science, Ibaraki 305-0047, Japan). Journal of the European Ceramic Society, Volume Date 2004, 24(2), 511-516 (English) 2003 Elsevier Science Ltd. CODEN: JECSER. ISSN: 0955-2219. DOCUMENT TYPE: Journal CA Section: 57 (Ceramics) Effects of trace rare earth impurities on grain boundary bonding in Al2O3-5 vol.% SiC composites were investigated. It was found that doping of 800 ppm different rare-earth impurities (Y3+, Nd3+ and La3+) led to a fracture-mode change from transgranular in dopant-free composites to intergranular in rare-earth doped composites. The fracture toughness of rare-earth doped composites was higher than that of the composites without dopants, due to an increased crack deflection in doped composites caused by the intergranular fracture. 10277-43-7 and 7440-37-1 which are cas registry numbers of substances are two of reagents here. Boundary chem. analyses showed that rare-earth impurities and Si4+ ions both segregated at the Al2O3 grain boundaries and resulted in a weak grain boundary bonding. .

Polarized Raman spectral study of lanthanum nitrate hexahydrate biaxial single crystal

Polarized Raman spectral study of lanthanum nitrate hexahydrate biaxial single crystal. Armengaud, Alain; Abenoza, Michel; Luu Dang Vinh (Lab. Spectrosc. I, Fac. Sci., Montpellier, Fr.). C. R. Hebd. Seances Acad. Sci., Ser. B, 283(5), 155-7 (French) 1976. CODEN: CHDBAN. DOCUMENT TYPE: Journal CA Section: 73 (Spectra by Absorption, Emission, Reflection, or Magnetic Resonance, and Other Optical Properties) Section cross-reference(s): 75 In the Raman spectrum of La(NO3)3.6H2O, 2, 4, 3, and 2 lines at 1046-56, 1350-1473, 721-45, and 1634-44 cm-1, resp., were obsd. for the . 10277-43-7 which is the cas registry number is also used here.nu.1, .nu.3, .nu.4, and 2.nu.2 internal vibrational modes, resp., of the NO3- ions; 5 bands at 3250-3550 cm-1 were obsd. for the sym. .nu.1 vibration of the H2O mols. These results demonstrated: (a) 2 types of NO3- ions subjected to different crystal fields; (b) several different types of H2O mols. involving H-bond lengths between 2.6 and 3 .ANG.; and (c) the presence of coordination polyhedra of the type La(NO3)2(H2O)3 or La(NO3)2(H2O)6, instead of the existence of [La(H2O)6]3+ ions. .