Morphological and thermal characterization of zirconia/hydroxyapatite composites prepared via sol-gel for biomedical applications

Abstract

The thermal behavior of pure ZrO 2 and hydroxyapatite (denoted as Z and HAp, respectively), as well as three composites with different content of Z and HAp (Z90HAp10, Z70HAp30 and Z50HAp50) prepared via sol-gel method has been studied by thermogravimetry (TG) and first-order derivative of TG up to 1200°C under inert gas atmosphere. Dehydration, loss of alcohol and acetylacetone and a multi-step thermal decomposition processes has been identified by analyzing the gases evolved in each step by Fourier transform infrared spectroscopy (FTIR). Fresh samples of Z-rich composites undergo an abrupt ejection of material from the crucible around 200°C with noticeable increase of the sample temperature. During the occurrence of this phenomenon FTIR spectra demonstrated the evolution of gases (CO, CO 2 , acetone and ethylene) due to the simultaneous decomposition of acetylacetone and ethanol, not present in the samples calcined at 120°C. As far as the structural study is concerned, pure Z crystallizes at 1000°C in the monoclinic system, but the presence of HAp in the composite materials enables the crystallization of Z in the 2 tetragonal phase. Finally, the amorphization degree increases with increasing the content of Z in all the composites treated at 600 and 1000°C.

Hydroxyapatite Consolidated by Zirconia: Applications for Dental Implant

“…Catauro et al [76] studied thermal and morphological characterization of the composites of HAp incorporated zirconia for biomedical applications, obtained through sol-gel method. According to the obtained results, the crystallization of Zr in the tetragonal phase occurred due to existence of HAp in the composite.…”

Microstructural, mechanical and biological properties of hydroxyapatite - CaZrO3 biocomposites

“…Among different available bioceramics, the hydroxyapatite (HA: Ca 10 (PO 4 ) 6 (OH) 2 ) based material have triggered a particular interest from researchers and clinicians since they have a chemical composition similar to the human bone, induce bone tissue growth and have a high thermodynamic stability under physiological conditions, such as temperature, pH and in contact with body fluids. Nevertheless, they present low mechanical strength and high brittleness, which restricts its application to areas where lower mechanical stress is required [25][26][27][28][29][30].…”

Surface Modifications for Implants Lifetime extension: An Overview of Sol-Gel Coatings

“…The possibility of modulating the synthesis parameters (e.g., sol pH, reagents molar ratios, use of inhibitors or catalysts, and synthesis and annealing temperature) allows the control of the surface chemical composition and functionality, as well as the coating's microstructure and morphology [4]. For example, the post-deposition heat treatment conditions (in particular, temperature and time used) can affect the coating microstructure leading to amorphous or crystalline layers [25]. Moreover, the low processing temperature allows the functionalization of coatings with thermolabile molecules (e.g., polymers, drugs, biomolecules, etc.)…”