Properties of calcium phosphate powder synthesized from calcium acetate and sodium hydrophosphate

Abstract

The properties of powder synthesized from calcium acetate and sodium hydrophosphate with the ratio [Ca 2+ ]/[PO 43-] of the starting reagents equal to 1 have been investigated. After synthesis brushite, monetite, and octacalcium phosphate were found in the powder. A substantial mass loss, equal to 26%, on heating is due to not only the decomposition of the phases found but also the removal of the byproducts, consisting of sodium acetate and acetic acid and present in the powder, of the reactions occurring when the solutions of the starting substances interact. After firing at temperatures above 900°C the phases b-Ca 2 P 2 O 7 , b-Ca 3 (PO 4 ) 2 , and Ca 10 Na(PO 4 ) 7 are found in the samples.

Structure and Properties of Ceramics Based on Monetite and Nanodispersed Silica

“…The formation of these phases is consistent with the data in [22,23]: (i) monetite undergoes a phase transition at 270-500°C and forms -Ca 2 P 2 O 7 , (ii) further increase in temperature up to 500-750°C results in the formation of the phase -Ca 2 P 2 O 7 , and (iii) the phase -Ca 2 P 2 O 7 forms at 1165°C. In turn, CPP can interact with the vapor at 280°C and form TCP.…”

Calcium Phosphate Powder Synthesized from Calcium Acetate and Ammonium Hydrophosphate for Bioceramics Application

“…Therefore, various stages of NO evolution were accompanied by the formation of H 2 O or CO 2 , and the overall mass loss was a result of several competing multistage processes involving both calcium phosphate species and ammonium acetate. It has been earlier revealed [18,20,23,24,26] that the reaction by-product consisting of carboxylic acids and their ammonium salts undergoes partial and then complete decomposition at temperatures below 800 • C. Therefore, the calcium phosphates powders containing carboxylic acids or their salts (ammonium, sodium [37], or potassium [38]) heat-treated at 400-800 • C were black-colored due to the formation of carbon or products of partial decomposition of organic substances present in the as-prepared samples.…”

Preparation of millimeter-scale fibrous octacalcium phosphate particles by homogeneous precipitation method

“…Generally, OCP is prepared by the chemical reaction, due to the careful pH control of the solution. The typical reactions for the formation of OCP are: (i) hydrolysis of calcium hydrogenphosphate dihydrate (CaHPO4•2H2O) 8,9 , (ii) hydrolysis of -tircalcium orthophosphate (-Ca3(PO4)2) 10,11 , and (iii) precipitation from the aqueous calcium phosphate solutions [12][13][14] . Relating to (i), the hydrolysis of CaHPO4•2H2O typically forms the needle-like OCP particles with the long-axis length of 2-5 m, reflecting the shapes of original CaHPO4•2H2O particles, e.g., tubular, needle-like, lath-like, and rectangular prismatic crystals 15 .…”