Crystallisation in apatite-mullite glass–ceramics as a function of fluorine content

Nanostructured apatite-mullite glass-ceramics for enhanced primary human osteoblast cell response

“…A glass with molar composition 4.85SiO2-3.25Al2O3-1.5P2O5-3.25CaO-1.75CaF2, chosen following a review of previous studies [14,16,17], was synthesised by melt-quench, as previously described [5,14]. This composition may produce crystal sizes and spatial density similar to the topographies used by Dalby et al [11].…”

Spherulitic crystallization of apatite–mullite glass-ceramics: Mechanisms of formation and implications for fracture properties

“…Spherulitic heterogeneous nucleation has also been reported in apatite-mullite glass-ceramics (SiO 2 ⋅ Al 2 O 3 ⋅ P 2 O 5 ⋅ CaO ⋅ CaF 2 ) by Stanton and Hill [28]. Upon heating to above the glass transition temperature, T g , the base glass undergoes amorphous phase separation (APS) into droplets rich in P, Ca, and F, surrounded by regions rich in Si and Al [10,27].…”

“…In particular, apatite based glass-ceramics have been shown to exhibit high fracture toughness, K Ic , values of more than 3 MPa ffiffiffiffi ffi m p ; this has been attributed to the highly acicular nature of the apatite crystals formed [2]. However, it has been noted that these crystals form within spherulitic apatite regions that can have a significant effect on fracture paths [28]. The present work examines the formation of these crystals in apatitemullite glass-ceramics and what implications they have for fracture toughness.…”

“…Upon heating to above the glass transition temperature, T g , the base glass undergoes amorphous phase separation (APS) into droplets rich in P, Ca, and F, surrounded by regions rich in Si and Al [10,27]. When fully crystallized, this gives bioactive fluorapatite crystals (FAp, Ca 5 (PO 4 ) 3 F) in a mullite matrix (Si 2 Al 6 O 13 ) [8] and in some cases anorthite (CaAl 2 Si 2 O 8 ) [28] is observed.…”

Crystallization in Na2O–Nb2O5–Al2O3–SiO2 glass–ceramics system with partial replacement of SnO2 for Al2O3

“…But the complexity of preparation procedure of the crystal growth technique limits theirs practical use. Recently, the controlled crystallization of ferroelectric crystals (BaTiO 3 , PbTiO 3 , LiNbO 3 , NaNbO 3 , KNbO 3 , etc.-perovskite type) in glasses by heat treatment process has been successfully performed and led to the development of ferroelectric materials in glass-ceramics form with pore-free, fine-grained microstructure and specific properties [1][2][3][4][5][6][7].…”