Formation of colloidal phosphorus particles in barium phosphate glasses

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In this Subject: <a title="Inorganic Chemistry" href="/content/subcat?j_subject=167&j_availability=">Inorganic Chemistry
By this author: J.M. Prison ;&nbsp; J.R. Martinelli

Authors: J.M. Prison; J.R. Martinelli

Source: Physics and Chemistry of Glasses - European Journal of Glass Science and Technology Part B, Volume 45, Number 4, August 2004 , pp. 268-271(4)

Publisher: Society of Glass Technology

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Abstract:

Barium phosphate glasses 40BaO.60 P₂O₅ mol% were prepared by melting mixtures of NH₄H₂PO₄ and BaCO₃. Coloured glasses were obtained after heat treatment at 520°C. The colour is caused by colloidal dispersions formed by phosphorus atoms that were reduced by hydrogen released from the decomposition of NH₄H₂PO₄. Samples were stored at room temperature for one year and x-ray diffraction and differential thermal analyses were performed to determine structural change. Colloidal particles formed during the glass preparation process are brought into contact with air when the glass monoliths are milled and participate in chemical reactions, finally forming the crystal phase Ba(H₂PO₄) ₂. After heating at 238°C, water molecules are released and Ba(H₂PO₄) ₂ is transformed to -Ba(PO₃) ₂. The latter compound is stoichiometrically consistent with the original glass composition.

Document Type: Research article

Publication date: 2004-08-01