title: Facile synthesis of calcium borate nanoparticles and  the annealing effect on their structure and size.
abstract: Calcium borate nanoparticles have been synthesized by a thermal treatment method via facile co-precipitation. Differences of annealing temperature and annealing time and their effects on crystal structure, particle size, size distribution and thermal stability of nanoparticles were investigated. The formation of calcium borate compound was characterized by X-ray diffraction (XRD) and Fourier Transform Infrared spectroscopy (FTIR), Transmission electron microscopy (TEM), and Thermogravimetry (TGA). The XRD patterns revealed that the co-precipitated samples annealed at 700 °C for 3 h annealing time formed an amorphous structure and the transformation into a crystalline structure only occurred after 5 h annealing time. It was found that the samples annealed at 900 °C are mostly metaborate (CaB(2)O(4)) nanoparticles and tetraborate (CaB(4)O(7)) nanoparticles only observed at 970 °C, which was confirmed by FTIR. The TEM images indicated that with increasing the annealing time and temperature, the average particle size increases. TGA analysis confirmed the thermal stability of the annealed samples at higher temperatures.
authors.affiliation: Department of Physics, Faculty of Science, University Putra Malaysia, 43400UPM Serdang, Selangor, Malaysia. maryam.erfani59@gmail.com
authors.forename: Maryam
authors.initials: M
authors.lastname: Erfani
authors.forename: Elias
authors.initials: E
authors.lastname: Saion
authors.forename: Nayereh
authors.initials: N
authors.lastname: Soltani
authors.forename: Mansor
authors.initials: M
authors.lastname: Hashim
authors.forename: Wan Saffiey B Wan
authors.initials: WS
authors.lastname: Abdullah
authors.forename: Manizheh
authors.initials: M
authors.lastname: Navasery
mesh_terms: D001881:Borates / Q000737:chemistry*; D017610:Calcium Compounds / Q000737:chemistry*; D015394:Molecular Structure; D053758:Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D010316:Particle Size; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D013816:Thermodynamics; D014961:X-Ray Diffraction
chemical_list: D001881:Borates; D017610:Calcium Compounds; C031316:calcium borate