Structural and mechanical properties of sol-gel prepared pyrochlore lanthanum niobates

被引：10

作者：

Brunckova, H. ^{[1
]}

Medvecky, L. ^{[1
]}

Hvizdos, P. ^{[1
]}

Durisin, J. ^{[1
]}

Girman, V. ^{[2
]}

机构：

[1] Slovak Acad Sci, Inst Mat Res, Kosice 04001, Slovakia

[2] Safarik Univ, Fac Sci, Inst Phys, Kosice 04154, Slovakia

来源：

JOURNAL OF MATERIALS SCIENCE | 2015年 / 50卷 / 22期

关键词：

RARE-EARTH ORTHONIOBATE; FERROELASTIC LANBO4; BEHAVIOR; PHASE; TRANSFORMATION; INDENTATION; SUBSTRATE; POWDERS; SHAPE; LOAD;

D O I：

10.1007/s10853-015-9274-8

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Lanthanum orthoniobate LaNbO4 (LN) precursors were prepared by a modified polymeric complex sol-gel method using Nb-tartrate in different solvents (ethanol or methanol) with calcination at 750 A degrees C. The monoclinic LaNbO4 and orthorhombic LaNb5O14 phases were formed after annealing at 900 A degrees C from precursors synthesized in ethanol (LNet) and methanol (LNmet), respectively. FTIR and Raman spectra confirmed different structures of LN at 900 A degrees C in both solvents. The microstructures indicate the strong effect of solvents on surface morphology. TEM and SAED patterns verified the monoclinic LaNbO4 and orthorhombic LaNb5O14 phases with ferroelastic domains at 750 and 900 A degrees C, respectively. Mechanical characterization was conducted for the first time by nanoindentation on the sol-gel derived LN after annealing at a low temperature. The hardness and elastic modulus of LNmet (LNet) were measured to be similar to 2.6(1.5) and similar to 45(30) GPa, respectively. The modulus and hardness of LNmet were higher in comparison with LNet. The strong solvent effect on mechanical properties of lanthanum niobate was confirmed.

引用

页码：7197 / 7207

页数：11

共 37 条

[1] Low temperature sintering of LaNbO4 proton conductors from freeze-dried precursors [J].

Amsif, M. ;

Marrero-Lopez, D. ;

Ruiz-Morales, J. C. ;

Savvin, S. ;

Nunez, P. .

JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, 2012, 32 (06) :1235-1244

[2]

Andoulsi R., 2012, Cerâmica, V58, P126

[3] Preparation and LPG-gas sensing characteristics of p-type semiconducting LaNbO4 ceramic material [J].

Balamurugan, C. ;

Lee, D. -W. ;

Subramania, A. .

APPLIED SURFACE SCIENCE, 2013, 283 :58-64

[4] Effect of substrate on microstructure and mechanical properties of sol-gel prepared (K, Na)NbO3 thin films [J].

Brunckova, H. ;

Medvecky, L. ;

Hvizdos, P. .

MATERIALS SCIENCE AND ENGINEERING B-ADVANCED FUNCTIONAL SOLID-STATE MATERIALS, 2013, 178 (04) :254-262

[5] Effect of solvent on phase composition and particle morphology of lanthanum niobates prepared by polymeric complex sol-gel method [J].

Brunckova, Helena ;

Medvecky, Lubomir ;

Hvizdos, Pavol ;

Girman, Vladimir .

JOURNAL OF SOL-GEL SCIENCE AND TECHNOLOGY, 2014, 69 (02) :272-280

[6] A co-precipitation technique of preparing LaNbO4 powders [J].

Gupta, U. N. ;

Pradhan, Sivaram ;

Muthurajan, H. ;

Kumar, H. H. ;

Kharat, D. K. ;

Ravi, V. .

JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 2007, 90 (08) :2661-2663

[7] Proton conduction in rare-earth ortho-niobates and ortho-tantalates [J].

Haugsrud, R ;

Norby, T .

NATURE MATERIALS, 2006, 5 (03) :193-196

[8] Transformation plasticity in TbPO4 and (Gd,Dy)PO4 orthophosphates during indentation of polycrystalline specimens [J].

Hay, R. S. ;

Boakye, E. E. ;

Mogilevsky, P. .

JOURNAL OF THE EUROPEAN CERAMIC SOCIETY, 2014, 34 (03) :773-781

[9]

Hofmann R, 1990, J INORG GEN CHEM, V583, P223

[10] Structure and luminescent properties of LaNbO4 synthesized by sol-gel process [J].

Hsiao, Y. J. ;

Fang, T. H. ;

Chang, Y. S. ;

Chang, Y. H. ;

Liu, C. H. ;

Ji, L. W. ;

Jywe, W. Y. .

JOURNAL OF LUMINESCENCE, 2007, 126 (02) :866-870

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