Nucleation, growth and characterization of LiB3O5 single crystals

Kannan, C. Ramesh; Kimura, Hideo; Miyazaki, Akimitsu; Ramasamy, P.

doi:10.1016/j.jcrysgro.2004.11.091

Cited by 10 publications

(6 citation statements)

References 19 publications

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“…H S reaches minimum for scratches parallel [010]. Indentation nanohardness H, however, followed the order H 001 <H 010 ≈ H 100 [38,40], and for Meyer microhardness H M 011 < H M 010 < H M 100 was found [38]. Hence the anisotropy of indentation microhardness is in agreement with indentation nanohardness.…”

Section: Resultsmentioning

confidence: 94%

“…However, only a few studies have become known so far. Authors of [40] found that the Vickers hardness of a top-seeded solution grown LBO crystal is 9.09 GPa along the b axis and 8.63 GPa along c. Appearance of cracks was observed for indentation loads > 0.9 N. Elastic coefficients for LBO have been determined by [41][42][43]. It was found [44] that the majority of dislocations in LBO crystals extends parallel to the [001] axis and (010) being their preferred slip plane.…”

Section: Example Lib 3 Omentioning

confidence: 99%

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About 200 years after Mohs – Nanoscratching LiB₃O₅

Paufler¹,

Shakhverdova

Бубнова

et al. 2008

Cryst. Res. Technol.

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Though simple scratch hardness tests after Mohs are still used today, the development of diamond nanoscratching equipment offers new possibilities to meet demands of modern nanotechnology. Preceding approaches to assign hardness values to materials are briefly reviewed, and scratch hardness is related to indentation hardness. Taking single-crystalline LiB 3 O 5 as an example, the dependence of scratch morphology on the direction of scratching is demonstrated quantitatively. The coefficient of friction depends on normal load and varies between 0.25 and 0.37. Moreover, it is oscillating during scratching thus reflecting processes at nanoscale. Dislocation etch pits were observed due to scratching. Scratching in the pastAt the end of the 17 th century people were already aware of the varying resistance of minerals and other materials against mechanical loading, in particular against scratching. Huygens (1690) noticed the fascinating fact that the cleavage plane of calcite may be scratched when moving the knife forward and may not when moving it in the opposite direction [1]. In 1722 Réaumur [2] differentiated the quality of steel, instead of testing it with the aid of a file, by scratching with seven different kinds of reference materials. Moreover, he prepared a steel bar with increasing hardness from one end to the other. The degree of hardness was attributed to the specimen according to the position on the bar which the specimen could scratch first. Linné (1768 and 1793) listed a number of terms relevant for an appropriate terminology of the mechanics of solids which has been adopted by other writers [3]. Then Werner [4] introduced in 1774 four categories of hardness (hard, semihard, soft, very soft) defined by the behaviour of the material when scratched by a knife or a file using gauge minerals for comparison. Following Werner, Hauy classified minerals according to their ability to scratch each other, assigning four grades to the materials scratching quartz, glass or calcite and those not scratching calcite, respectively [5].Almost 200 years ago, in 1812 Carl Friedrich Christian Mohs published the first approach to the hardness scale still used today [6]. He considered hardness (combined with several other properties) as a distinguishing feature of solids. Later he introduced, on the basis of the definition of hardness, the ten-stage hardness scale (now named after him) and instructions for its realisation [7] (His definition reads:' Härte ist der Widerstand,welchen die festen Mineralien der Verschiebung ihrer Theile entgegensetzen. Die Größe dieses Widerstandes heißt Grad der Härte.'; "...daß jedes Mineral, welches ein anderes ritzt, von demselben aber nicht geritzt wird, härter als dieses sey..."; For a biography cf. Rösler [18]). Pansner (1813) was seemingly not aware of Mohs' scale when he proposed a subdivision of all minerals into four hardness classes (represented by diamond, steel, copper, and lead etalons) with the additional subsubdivision into mass density subclasses [8]. The anisotropy of the depth...

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Section: Resultsmentioning

confidence: 94%

Section: Example Lib 3 Omentioning

confidence: 99%

About 200 years after Mohs – Nanoscratching LiB₃O₅

Paufler¹,

Shakhverdova

Бубнова

et al. 2008

Cryst. Res. Technol.

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“…[5] for this crystal plane of LBO crystal grown by the TSSG method with B 2 O 3 as a solvent. Similarly, the microhardness H M ~ 7.86 GPa at a load of 0.245 N and ~ 6.9 GPa at a load of 0.49 N measured for the (001) plane at one orientation of indent (φ=0) is consistent with the value H M = 8.63 GPa obtained in [5] for the direction along the c axis of the LBO crystal prepared by the TSSG method with B 2 O 3 as a solvent.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, the study of properties governing the applicability of LBO single crystals is important. A number of papers devoted to optical properties [2,3,[8][9][10], electrical conductivity [11], thermal expansion [1,6,[11][12][13], heat capacity [14], phase relationships [15,16], pyro- [6], piezo- [6,17] and dielectric constants [6,11], structural (bulk [1,18] as well as surface [19]), hygroscopic [7] and growth [5,20,21] properties including defects [20] of LBO have been published. Moreover, the electron density has been measured [22,23].…”

Section: Introductionmentioning

confidence: 99%

“…Phonon spectra have been calculated by [12] and measured by [24]. Authors of [5] found that the Vickers hardness of a top-seeded solution grown (TSSG) LBO crystal is 9.09 GPa along the b axis and 8.63 GPa along c. Appearance of cracks was observed for indentation loads > 0.9 N. As solvent in [5], B 2 O 3 was used since it yields more stability to the solution than that of a MoO 3 modified solvent. The 9 ____________________ © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim www.crt-journal.org elastic coefficients for LBO have been determined completely by [6,17] and in part by [4].…”

Section: Introductionmentioning

confidence: 99%

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Mechanical properties of single crystalline and glassy lithium triborate

Shakhverdova¹,

Paufler

Бубнова

et al. 2008

Cryst. Res. Technol.

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Mechanical properties of LiB 3 O 5 single crystal plates with different orientation as well as of glass with the same composition have been investigated. The nano-(H) and microhardness (H M ), the reduced Young's modulus (E r ) and the crack behaviour of the samples were studied. Both hardness and Young's modulus of glass appeared smaller in comparison to corresponding single crystal data (H ~ 7 -8 GPa, H M~ 6 GPa, E r ~ 70 -80 GPa for glass and H ~10 -15 GPa, H M~6 -11 GPa, E r~ 93 -155 GPa for single crystal). H, E r , and the plane of crack propagation proved orientation-dependent. Cracks in the glass sample were not observed up to 0.49 N microindentation load, whereas for the single crystal the cracks appeared already at 0.098N. In single crystals the observed cleavage planes {211} and/or {412} are oriented nearly parallel to planes of B-O rings.

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