Influence of Si substitution on the reactivity of a-tricalcium phosphate

Silicon substituted calcium phosphates have been widely studied over the last ten years due to their enhanced osteogenic properties. Notwithstanding, the role of silicon on a-TCP reactivity is not clear yet. Therefore, the aim of this work was to evaluate the reactivity and the properties of Si-a-TCP in comparison to a-TCP. Precursor powders have similar properties regarding purity, particle size distribution and specific surface area, which allowed a better comparison of the Si effects on their reactivity and cements properties. Both Si-a-TCP and a-TCP hydrolyzed to a calcium-deficient hydroxyapatite when mixed with water but their conversion rates were different. Si-a-TCP exhibited a slower setting rate than a-TCP, i.e. kSSA for Si-TCP (0.021 g·m- 2·h- 1) was almost four times lower than for a-TCP (0.072 g·m- 2·h- 1). On the other hand, the compressive strength of the CPC resulting from fully reacted Si-a-TCP was significantly higher (12.80 ± 0.38 MPa) than that of a-TCP (11.44 ± 0.54 MPa), due to the smaller size of the entangled precipitated apatite crystals.Preprin

Influence of Si substitution on the reactivity of α-tricalcium phosphate

Silicon substituted calcium phosphates have been widely studied over the last ten years due to their enhanced osteogenic properties. Notwithstanding, the role of silicon on α-TCP reactivity is not clear yet. Therefore, the aim of this work was to evaluate the reactivity and the properties of Si-α-TCP in comparison to α-TCP. Precursor powders have similar properties regarding purity, particle size distribution and specific surface area, which allowed a better comparison of the Si effects on their reactivity and cements properties. Both Si-α-TCP and α-TCP hydrolyzed to a calcium-deficient hydroxyapatite when mixed with water but their conversion rates were different. Si-α-TCP exhibited a slower setting rate than α-TCP, i.e. kSSA for Si-TCP (0.021 g·m− 2·h− 1) was almost four times lower than for α-TCP (0.072 g·m− 2·h− 1). On the other hand, the compressive strength of the CPC resulting from fully reacted Si-α-TCP was significantly higher (12.80 ± 0.38 MPa) than that of α-TCP (11.44 ± 0.54 MPa), due to the smaller size of the entangled precipitated apatite crystals.Title in WOS: Influence of Si substitution on the reactivity of alpha-tricalcium phosphate</p

Influence of Si substitution on the reactivity of a-tricalcium phosphate

Silicon substituted calcium phosphates have been widely studied over the last ten years due to their enhanced osteogenic properties. Notwithstanding, the role of silicon on a-TCP reactivity is not clear yet. Therefore, the aim of this work was to evaluate the reactivity and the properties of Si-a-TCP in comparison to a-TCP. Precursor powders have similar properties regarding purity, particle size distribution and specific surface area, which allowed a better comparison of the Si effects on their reactivity and cements properties. Both Si-a-TCP and a-TCP hydrolyzed to a calcium-deficient hydroxyapatite when mixed with water but their conversion rates were different. Si-a-TCP exhibited a slower setting rate than a-TCP, i.e. kSSA for Si-TCP (0.021 g·m- 2·h- 1) was almost four times lower than for a-TCP (0.072 g·m- 2·h- 1). On the other hand, the compressive strength of the CPC resulting from fully reacted Si-a-TCP was significantly higher (12.80 ± 0.38 MPa) than that of a-TCP (11.44 ± 0.54 MPa), due to the smaller size of the entangled precipitated apatite crystals

Synthesis of Wollastonite Powders by Combustion Method: Role of Amount of Fuel

The objective of this work has been the synthesis of wollastonite by solution combustion method. The novelty of this work has been obtaining the crystalline phase without the need of thermal treatments after the synthesis. For this purpose, urea was used as fuel. Calcium nitrate was selected as a source of calcium and colloidal silica served as a source of silicon. The effect of the amount of fuel on the combustion process was investigated. Temperature of the combustion reaction was followed by digital pyrometry. The obtained products were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and specific surface area. The results showed that the combustion synthesis provides nanostructured powders characterized by a high surface area. When excess of urea was used, wollastonite-2M was obtained with a submicronic structure