Fine crystal structure of porous corundum ceramics

Grigoriev, M. V.; Кулъков, С. Н.

doi:10.1007/s11182-011-9565-8

Cited by 4 publications

(2 citation statements)

References 7 publications

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“…A promising process for fabrication of high-porosity ceramics without using a standard practice based on burning out additives and pore agents is the mixing of coarse-grained and ultrafine-grained powders [6]. In this case, the pore geometry depends on the coarse-grained powder particle size and shape.…”

Section: Introductionmentioning

confidence: 99%

Structures and properties of alumina-based ceramic for reconstructive oncology

Grigoriev¹,

Кулъков²

2016

AIP Conference Proceedings

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Abstract. The microstructure of alumina ceramics based on powders with a varying grain size has been investigated. Both commercial alumina powders and those fabricated by denitration of aluminum salts in high-frequency discharge plasma were used. It is shown that the variation of the sintering temperature and morphology of the initial powders of the particles leads to a change of the pore structure of ceramics from pore isolated clusters to a structure consisting of a ceramic skeleton and a large pore space. Changing the type of pore structure occurs at about 50% of porosity. The ceramic pore size distribution is bimodal. Dependencies final density vs initial density are linear; at the same time with increasing temperature, inclination of changes from positive to negative, indicating the change of sealing mechanisms. Extrapolation of these curves showed that they intersect with the values of density of about 2 g/cm 3 , which indicates the possibility of producing non-shrink ceramics. It is shown that the strength increases with increasing nanocrystalline alumina content in powder mixture. A change in the character the pore structure is accompanied by a sharp decrease in strength, which corresponds to the percolation transition in ceramics. These results showed that it is possible to obtain ceramic materials with the structure and properties similar to natural bone.

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Section: Introductionmentioning

confidence: 99%

Structures and properties of alumina-based ceramic for reconstructive oncology

Grigoriev¹,

Кулъков²

2016

AIP Conference Proceedings

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“…Some papers present more complete characterisation based on XRD patterns including mean crystallite size and strain (e.g. [8][9][10][11]), crystallite size distribution [12], and rarely crystallite size and shape distributions [13]. Densification and re-crystallisation can be achieved by overgrinding of nanocrystalline corundum [14] but usually the maximum of frequency of crystallite size distributions migrates to smaller crystallite sizes after milling (e.g.…”

Section: Introductionmentioning

confidence: 99%

Crystalline Microstructure of Corundum Fillers Determined from Powder X-Ray Diffraction Patterns

et al. 2016

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X-ray-diffraction microstructural analysis was performed for corundum powders produced from Bayer aluminium hydroxides in different ways and for high purity corundum powders produced from other raw materials. Crystalline microstructure characterised by prevalent crystallite shape, volume-weighted crystallite size distribution and second-order crystalline lattice strain distribution was determined through modelling crystallite shapes as hexagonal prisms, with the resulting mean volume-weighted standardised crystallite size in the range 406-1941 Å, height-to-base-diagonal ratio in the range 0.68-0.94 and the mean-absolute second-order strain in the range 0.028-0.087%. Crystallite size distributions were found to be well approximated as bimodal logarithmic-normal ones and consequently four types of microstructure were recognized as depending on precursors and methods of production.

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