Mechanical properties of oriented mica glass ceramic

Habelitz, Stefan; Carl, G.; Rüssel, Christian; Thiel, Sven; Gerth, U.; Schnapp, Jürgen Dieter; Jordanov, A.; Knake, Harald

doi:10.1016/s0022-3093(97)00299-8

Cited by 71 publications

(49 citation statements)

References 3 publications

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“…For this reason, mica crystals posses excellent cleavages perpendicular to the c-axis. By contrast, fracture propagation across the basal plane is more difficult inducing fractures to the cleavage planes or mica-glass interfaces 26) . The commercial mica glass-ceramic materials used for CAD/CAM, such as Dicor (tetrasilicic mica: KMg2.5Si4O10F2) and Macor (fluorophogopite: KMg3AlSi3O10F2) contain K + as the interlayer ions 27) .…”

Section: Discussionmentioning

confidence: 99%

“…The interlocking of the randomly orientated mica crystals is a crucial characteristic in developing good machinability in glass-ceramics 5) . Since the crystals are in mutual contact, a series of deflections, branching and often blunting of cracks absorb energy 26) allowing for good machining. GCF 4.0 contains the highest amount of mica resulting in the highest degree of interlocking.…”

Section: Discussionmentioning

confidence: 99%

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Machinable glass-ceramics forming as a restorative dental material

et al. 2011

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MgO, SiO2, Al2O3, MgF2, CaF2, CaCO3, SrCO3, and P2O5 were used to prepare glass-ceramics for restorative dental materials. Thermal properties, phases, microstructures and hardness were characterized by DTA, XRD, SEM and Vickers microhardness. Three-point bending strength and fracture toughness were applied by UTM according to ISO 6872: 1997(E). XRD showed that the glass crystallized at 892°C (second crystallization temperature+20°C) for 3 hrs consisted mainly of calcium-mica and fluorapatite crystalline phases. Average hardness (3.70 GPa) closely matched human enamel (3.20 GPa). The higher fracture toughness (2.04 MPa√m) combined with the hardness to give a lower brittleness index (1.81 µm −1/2 ) which indicates that they have exceptional machinability. Bending strength results (176.61 MPa) were analyzed by Weibull analysis to determine modulus value (m=17.80). Machinability of the calcium micafluorapatite glass-ceramic was demonstrated by fabricating with CAD/CAM.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Machinable glass-ceramics forming as a restorative dental material

et al. 2011

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“…Mica structures strongly exhibit excellent machinability due to their sheet structure; it provides different mechanical behavior depending on directions. While mica crystals have cleavage planes perpendicular to the c-axis regarding to weak bonding of alkali layers, fracture propagation across the basal plane of mica is more difficult [10]. There are different approaches about diopside phase crystallization; some of these theories are that precipitated mica crystals have a role as nucleating site of diopside phase regarding mica crystals are crystallized in lower temperatures than densification temperature of sintered glass-ceramic or Fe 2 O 3 has similar nucleating site effect for diopside crystallization [9][10][11].…”

Section: Materials and Equipmentmentioning

confidence: 99%

Development of Machinable Glass-Ceramics Produced from Vermiculite

2017

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In this study, machinable glass-ceramics were produced from vermiculite and K2CO3, SiO2, Al2O3 and MgF2 as additives by melting process. The starting materials were mixed together and milled in a mill with alumina ball for 2 h. The mixed powders were melted by aluminum crucible at 1500• C. The melted glass was cast into graphite mold, and then it was exposed to crystallization heat treatment for glass-ceramic transformation. The glass-ceramic samples were characterized with X-ray diffraction analysis, scanning electron microscopy, mechanical tests such as hardness, fracture toughness and machinability test. The results indicate that machinability properties can be obtained from vermiculite based glass-ceramic with some additives.

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“…Compressible seals from the mica group are usually used in a form of mica paper or other highly anisotropic forms [6]. Therefore a need for sufficient experimental data of the chosen set of materials is a necessity for the stack designer.…”

Section: Introductionmentioning

confidence: 99%