Synthesis and characterisation of new phosphate and fluorophosphate materials

Rutter, Julie (2013). Synthesis and characterisation of new phosphate and fluorophosphate materials. University of Birmingham. Ph.D.

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Abstract

This thesis focuses on the use of the monofluorophosphate anion to synthesise a range of materials as potential biomaterials. Here we report the novel synthesis of a monazite structured SrPO\(_3\)F, formed from a readily available PO\(_3\)F\(^{2-}\) precursor via a precipitation reaction. Subsequently, through modifications to the reaction temperature a novel hydrated phase has also been synthesised. Both structures consist of distorted PO\(_3\)F\(^{2-}\) tetrahedron with an apparent ordering of the P-F bond.

SrPO\(^3\)F is the first example of a monazite system containing divalent cations. To investigate the compositional tolerance of this system, a range of mixed metal systems were explored using Ca\({^2+}\), Ba\(^{2+}\), Eu\(^{2+}\). The incorporation of trivalent ions (La\(^{3+}\) and PO\(_4\)\(^{3-}\)) into the SrPO\(_3\)F phase was pursued as it has been reported previously that low levels of Sr\(^{2+}\) incorporation into LaPO\(_4\) produced a proton conducting material.

In addition, a successful synthesis of a modified gypsum system, involving inclusion of fluorophosphate (Ca(SO\(_4\))x(PO\(_3\)F)1-x·2H\(_2\)O, where x = 0-1), has been achieved via a precipitation reaction. Initial solubility results suggest that cements formed with calcium fluorophosphates offer greater water stability, a current limiting factor in the wider use of gypsum.

This thesis also describes a study into the stabilisation of synthetic amorphous calcium carbonate (ACC) using the orthophosphate, fluorophosphate and pyrophosphate species. Results suggest that crystallisation of ACC is inhibited through exposure to appropriate levels of these simple inorganic species orthophosphate, fluorophosphate and pyrophosphate.

Type of Work:

Thesis (Doctorates > Ph.D.)

Award Type:

Doctorates > Ph.D.

Supervisor(s):