title: Sol-gel preparation and high-energy XRD study of (CaO)x(TiO2) 0.5-x(P2O5)0.5 glasses (x = 0 and 0.25).
abstract: Glasses from the CaO-TiO2-P2O5 system have potential use in biomedical applications. Here a method for the sol-gel synthesis of the ternary glass (CaO)0.25(TiO2)0.25(P2O5)0.5 has been developed. The structures of the dried gel and heat-treated glass were studied using high-energy X-ray diffraction. The structure of the binary (TiO2)0.5(P2O5)0.5 sol-gel was studied for comparison. The results reveal that the heat-treated (CaO)0.25(TiO2)0.25(P2O5)0.5 glass has a structure based on chains and rings of PO4 tetrahedra, held together by a combination of electrostatic interaction with Ca2+ ions and by corner-sharing oxygen atoms with TiO6 octahedra. In contrast, the (TiO2)0.5(P2O5)0.5 glass has a structure based on isolated P2O7 units linked together by corner-sharing with TiO6 groups. The results suggest that both the dried gels possess open porous structures. For the (CaO)0.25(TiO2)0.25(P2O5)0.5 sample there is a significant increase in Ca-O coordination number with heat treatment.
authors.affiliation: School of Physical Sciences, University of Kent, Canterbury CT2 7NH, UK. dmp@kent.ac.uk
authors.forename: David M
authors.initials: DM
authors.lastname: Pickup
authors.forename: Kate M
authors.initials: KM
authors.lastname: Wetherall
authors.forename: Jonathan C
authors.initials: JC
authors.lastname: Knowles
authors.forename: Mark E
authors.initials: ME
authors.lastname: Smith
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Newport
mesh_terms: D001672:Biocompatible Materials; D002118:Calcium / Q000737:chemistry; D017610:Calcium Compounds / Q000737:chemistry*; D005782:Gels; D005898:Glass; D007477:Ions; D008422:Materials Testing; D015233:Models, Statistical; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen / Q000737:chemistry; D044367:Phase Transition; D055672:Static Electricity; D013499:Surface Properties; D023822:Tissue Engineering; D014025:Titanium / Q000737:chemistry*; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; D017610:Calcium Compounds; D005782:Gels; D007477:Ions; D010087:Oxides; C009495:titanium dioxide; C016538:lime; D014025:Titanium; D010100:Oxygen; D002118:Calcium