Bulk Processing of Hydroxyapatite Nanopowder Using Radio Frequency Induction Plasma

Abstract

Spherical hydroxyapatite (HA) nanopowder was synthesized at a rate of 20 g/h from HA sol using a 30 kW inductively coupled radio frequency plasma spray system. The HA sol was axially fed with a water‐cooled steel probe in the lower temperature region of the supersonic plasma nozzle, which helped in HA phase stabilization. The HA powder was synthesized at plate power between 19 and 28 kW. Particle size, surface area, particle morphology, and phase composition of the synthesized powder were evaluated using transmission electron microscopy, BET specific average surface area, X‐ray diffraction (XRD), and Fourier‐transformed infrared spectroscopy. The synthesized nanopowder was spherical in nature, with the particle size ranging from 30 to 70 nm. The increase in plate power resulted in a decrease in particle size. XRD results indicated HA to be the primary phase along with phase decomposition products, such as tricalcium phosphate and calcium oxide. Cytotoxicity behavior was studied using human osteoblast cells to ensure biocompatibility.

Antibacterial and biological characteristics of silver containing and strontium doped plasma sprayed hydroxyapatite coatings

“…The HA particles are discharged at a high speed, 510 m/s, in the lower region of the plasma arc where temperatures are relatively low and therefore, phase decomposition and amorphous phase formation is restricted due to reduced exposure to the plasma flame. Our previous studies with this nozzle have demonstrated the ability to retain high phase purity and crystallinity[25,30,33]. The XRD data, shown in Figure 1, indicates very little phase decomposition and amorphous phase formation in all samples.…”

Induction plasma sprayed Sr and Mg doped nano hydroxyapatite coatings on Ti for bone implant

“…The FTIR spectra of the HA, Sr‐HA, and Mg‐HA coatings are shown in Figure 2. The antisymmetric (ν 3 ) PO stretching modes of HA phosphate groups were noticed between 970 and 1190 cm −1 , whereas the PO (ν 1 ) symmetric stretching mode appeared at 960 cm −1 26, 27. The antisymmetric (ν 4 ) PO bending modes of the phosphate groups were found in the region of 540 to 660 cm −1 .…”

Fabrication, Properties and Applications of Dense Hydroxyapatite: A Review

“…Various methodologies [ 126 , 127 , 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 , 136 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 , 145 ] have been used to prepare nanosized HAp with different sizes and morphologies [ 126 ]. Sol-gel [ 127 , 128 , 129 ], co-precipitation [ 130 ], wet-chemical synthesis [ 131 , 132 ], hydrothermal synthesis [ 133 , 134 ], mechano-chemical synthesis [ 135 ], mechanical alloying [ 135 ], ball milling [ 136 ], radiofrequency induction plasma [ 137 ], vibro-milling of bones [ 138 ], liquid-solid synthesis [ 139 , 140 , 141 ], electrocrystallization [ 142 ], solvothermal [ 143 ], hydrolysis of calcium orthophosphates, laser-induced fragmentation of HAp micro-particles in water, the electrospinning technique [ 144 ] and radiofrequency magnetron sputtering [ 145 ] are some of the techniques. Nano-HAp is reported [ 146 ] to have better bioactivity than microsized HAp.…”