Mechanism of incorporation of oxide and aluminum oxyhydroxide into KDP crystalline matrix

Abstract

The mechanism of incorporation of aluminium oxide and aluminum oxyhydroxide into potassium dihydrogen phosphate (KDP) crystalline matrix is investigated. It was observed that: (1) aluminum phosphate is not formed on the surface of particles of aluminium oxide and aluminum oxyhydroxide particles in 1 M KDP solution irrespective of the treatment conditions and the size and phase composition of the particles, (2) phosphate groups are adsorbed on the surface of aluminum oxyhydroxide and aluminum oxide particles, and (3) a maximum observed at 1076 cm−1 of the absorption band in the 950–1200 cm−1 region of the infrared spectra is associated with the vibrations of phosphate ions adsorbed on the surface of the investigated particles. It is proposed that the phosphate groups adsorbed on the surface of aluminum oxyhydroxide and aluminum oxide particles interact with the phosphate groups of the growing KDP crystals by means of creation of hydrogen bonds between them, and that this interaction results in the “attraction” of the particles to the surface of the growing crystal and its subsequent overgrowth.