scholarly journals Effect of ultraviolet irradiation or diffuse discharge plasma on structure and surface electrical charge of micro-arc calcium phosphate coatings

2021 ◽  
Vol 2064 (1) ◽  
pp. 012077
Author(s):  
E G Komarova ◽  
E A Kazantseva ◽  
V S Ripenko ◽  
A Zharin ◽  
Y P Sharkeev
Keyword(s):  
Uv Irradiation ◽  
Runaway Electron ◽  
Discharge Plasma ◽  
Amorphous Structure ◽  
Electrical Charge ◽  
X Ray ◽  
Diffuse Discharge ◽  
Phosphate Coatings ◽  
Micro Arc Oxidation ◽  
Calcium Phosphate Coatings

Abstract The studies of the effect of ultraviolet (UV) irradiation and plasma of a runaway electron preionized diffuse discharge (REP DD) post-treatments on the surface structure and electrical charge of the micro-arc oxidation (MAO) coatings were performed. The UV irradiation and plasma treatment did not effect on the morphology, roughness and thickness of the MAO coatings. However, these post-treatments led to formation of the small fraction of the crystalline CaHPO4phase in the X-ray amorphous structure of the coatings. Moreover, the UV and REP DD plasma treatments increased the electrostatic potential (EP) negative values from –85 mV to –126 mV of the coatings in the following order: MAO < MAO/UV (for 5 min) < MAO/Plasma (with 10,000 pulses) < MAO/UV (for 20 min) < MAO/Plasma (with 80,000 pulses).

scholarly journals Effect of power of ultrasound during micro-arc oxidation on morphology, elemental and phase composition of calcium phosphate coatings

2021 ◽  
Vol 2064 (1) ◽  
pp. 012057
Author(s):  
E A Kazantseva ◽  
E G Komarova
Keyword(s):  
Phase Composition ◽  
Oxidation Process ◽  
X Ray ◽  
Phosphate Coatings ◽  
The Us ◽  
Local Destruction ◽  
Structure Heterogeneity ◽  
Micro Arc Oxidation ◽  
Morphological Transformations ◽  
Calcium Phosphate Coatings

Abstract The effect of the magnitude of the US (ultrasound) power applied during the MAO (micro arc oxidation) process on the morphology, elemental and phase composition of the CaP coatings was studied. The US at different power (50-200 W) applying during the MAO process led to the local destruction of the structure elements (spheres and pores) and local filling the pore spaces on the coating surface, and to the formation of local macro-pores inside the coatings near the substrate. Such morphological transformations led to the surface and structure heterogeneity of the coatings, increasing of the surface roughness from 3.0 to 4.5 μm and of the thickness from 50 to 60 μm. The US application at different power did not affect significantly the elemental composition of the coatings. At the same time, under applied US with power more than 100 W, the state of the coatings transformed from X-ray amorphous to the quasiamorphous with the small incorporation of crystalline phases of CaHPO4 and β-Ca2P2O7.

scholarly journals Effect of the Porosity, Roughness, Wettability, and Charge of Micro-Arc Coatings on the Efficiency of Doxorubicin Delivery and Suppression of Cancer Cells

Coatings ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 664
Author(s):  
Mariya Borisovna Sedelnikova ◽  
Ekaterina G. Komarova ◽  
Yurii P. Sharkeev ◽  
Valentina V. Chebodaeva ◽  
Tatiana V. Tolkacheva ◽  
...  
Keyword(s):  
Calcium Phosphate ◽  
X Ray Diffraction ◽  
Oxidation Method ◽  
X Ray ◽  
Phosphate Coatings ◽  
Micro Arc Oxidation ◽  
Calcium Phosphate Coatings ◽  
Adsorption Desorption ◽  
Kinetics Of ◽  
Scanning Electron

Porous calcium phosphate coatings were formed by the micro-arc oxidation method on the surface of titanium for the loading and controlled release of the anticancer drug doxorubicin. The coatings’ morphology and microstructure were examined by scanning electron microscopy. The phase composition was determined with the help of X-ray diffraction analysis. Studies of the hydrophilic properties of the coatings and their zeta potential were carried out. Data on the kinetics of doxorubicin adsorption-desorption were obtained. In addition, the effect of calcium phosphate coatings impregnated with doxorubicin on the viability of the Neuro-2a cell line was revealed. The coating formed at low voltages of 200–250 V contained a greater number of branched communicating pores, and therefore they were able to adsorb a greater amount of doxorubicin. The surface charge also contributes to the process of the adsorption-desorption of doxorubicin, but this effect is not fully understood and further studies are required to identify it.

Principal Physics of Oblique Sputtering of Calcium Phosphate Coatings Using RF-Magnetron Discharge Plasma

2021 ◽  
Vol 63 (11) ◽  
pp. 1891-1897
Author(s):  
K. A. Prosolov ◽  
O. A. Belyavskaya ◽  
V. V. Lastovka ◽  
M. V. Chaikina ◽  
Yu. P. Sharkeev
Keyword(s):  
Calcium Phosphate ◽  
Discharge Plasma ◽  
Magnetron Discharge ◽  
Phosphate Coatings ◽  
Calcium Phosphate Coatings

Effect of Substrate Temperature on Properties of Nano-Scale Functionally Graded Calcium Phosphate Coatings

2006 ◽  
Author(s):  
Travis Blalock ◽  
Xiao Bai ◽  
Afsaneh Rabiei
Keyword(s):  
Electron Microscopy ◽  
Calcium Phosphate ◽  
Substrate Temperature ◽  
Ion Beam ◽  
Processing Parameters ◽  
Functionally Graded ◽  
Cross Sectional ◽  
X Ray ◽  
Phosphate Coatings ◽  
Calcium Phosphate Coatings

The effect of substrate temperature and processing parameters on microstructure and crystallinity of calcium phosphate coatings deposited on heated substrates in an Ion Beam Assisted Deposition (IBAD) system are being studied. The experimental procedures include mechanical testing and film thickness measurements using bonding strength and profilometery. Cross-sectional scanning transmission electron microscopy (STEM) with energy dispersive X-ray spectroscopy (EDX) through the thickness of the film as well as scanning electron microscopy (SEM) with EDX at the top surface of the film was performed to evaluate the microstructure of the film. The coating crystallinity was studied through X-ray diffraction (XRD). The information gained from current analysis on the set temperature coatings will be used to refine the processing techniques of the Functionally Graded Hydroxyapatite (FGHA) coating.

Bioactivity, Wear and Corrosion Resistant Properties of Rare Earth/Calcium Phosphate Composite Coatings

2008 ◽  
Vol 368-372 ◽  
pp. 1194-1197 ◽  
Author(s):  
Chen Ma ◽  
Ying Hui Wang ◽  
Mu Qin Li ◽  
Li Jie Qu
Keyword(s):  
Rare Earth ◽  
Calcium Phosphate ◽  
Composite Coatings ◽  
Xrd Analysis ◽  
Wear Properties ◽  
Corrosion Resistant ◽  
Phosphate Coatings ◽  
Wear And Corrosion ◽  
Micro Arc Oxidation ◽  
Calcium Phosphate Coatings

Rare earth/calcium phosphate composite coatings were fabricated on the surface of Ti-6Al-4V by micro-arc oxidation (MAO) technique. The wear properties and corrosion resistant of rare earth/ calcium phosphate composite coatings in the simulated body fluid (SBF) have been investigated and the bioactivity of the composite coatings were evaluated. The results show that the friction coefficient of the composite coatings in the SBF is only 0.15~0.18 and the anode polarization potential of the coating has been obviously enhanced about 0.18V compared with that of coatings of calcium phosphate coatings. So the composite coatings have excellent wear and corrosion resistant properties. XRD analysis indicates that the composite coatings can induce hydroxyapatite to form on its surface after soaked in SBF for 9d, which shows that the composite coatings own good bioactivity.

A Study to the Surface Characteristics of RF Magnetron Sputtered Bioglass - and Calcium Phosphate Coatings

2005 ◽  
Vol 284-286 ◽  
pp. 187-190 ◽  
Author(s):  
Joop G.C. Wolke ◽  
E. Vandenbulcke ◽  
B. van Oirschot ◽  
John A. Jansen
Keyword(s):  
Surface Characteristics ◽  
Amorphous Structure ◽  
Microscopical Examination ◽  
X Ray Diffraction ◽  
Phosphate Coatings ◽  
Dissolution Properties ◽  
Physico Chemical ◽  
Sputter Coating ◽  
Electron Microscopical ◽  
Calcium Phosphate Coatings

The RF magnetron sputter technique was used to deposit Bioglass (BG) and hydroxyapatite (HA) coatings onto titanium substrates. In the current study, the physico-chemical and dissolution properties of various deposited coatings were investigated. X-ray diffraction demonstrated that the as-sputtered coatings had an amorphous structure, a heattreatment for 2 hours at 600°C changed only the HA coating into a crystalline apatite structure. Dissolution experiments demonstrated that all the amorphous coatings dissolved during the incubation for 4 weeks in simulated body fluid, while all the heattreated sputter coatings were still maintained. In contrast with the HA heattreated sputter coatings all the bioglass containing sputter coatings showed the formation of a crystalline apatite phase. Scanning electron microscopical examination of the sputtered coatings demonstrated that on all the heattreated BG/HG sputter coating a thick CaP precipitate was formed, while on the BG sputter coating occasionally a globular precipitate was observed.

Diffuse discharge, runaway electron, and x-ray in atmospheric pressure air in an inhomogeneous electrical field in repetitive pulsed modes

2011 ◽  
Vol 98 (2) ◽  
pp. 021503 ◽  
Author(s):  
Victor F. Tarasenko ◽  
Evgenii Kh. Baksht ◽  
Alexander G. Burahenko ◽  
Yuliya V. Shut’ko
Keyword(s):  
Atmospheric Pressure ◽  
Runaway Electron ◽  
Electrical Field ◽  
X Ray ◽  
Diffuse Discharge

scholarly journals X-ray radiation and runaway electron beams generated during discharges in atmospheric-pressure air at rise times of voltage pulse of 500 and 50 ns

2018 ◽  
Vol 36 (2) ◽  
pp. 186-194 ◽  
Author(s):  
D.A. Sorokin ◽  
V.F. Tarasenko ◽  
Cheng Zhang ◽  
I.D. Kostyrya ◽  
Jintao Qiu ◽  
...  
Keyword(s):  
Current Pulse ◽  
Breakdown Voltage ◽  
High Voltage ◽  
Rise Time ◽  
Atmospheric Pressure ◽  
Voltage Pulse ◽  
Runaway Electron ◽  
Electron Beams ◽  
X Ray ◽  
Diffuse Discharge

AbstractThe parameters of X-ray radiation and runaway electron beams (RAEBs) generated at long-pulse discharges in atmospheric-pressure air were investigated. In the experiments, high-voltage pulses with the rise times of 500 and 50 ns were applied to an interelectrode gap. The gap geometry provided non-uniform distribution of the electric field strength. It was founded that at the voltage pulse rise time of 500 ns and the maximum breakdown voltage Um for 1 cm-length gap, a duration [full width at half maximum (FWHM)] of a RAEB current pulse shrinks to 0.1 ns. A decrease in the breakdown voltage under conditions of a diffuse discharge leads to an increase in the FWHM duration of the electron beam current pulse up to several nanoseconds. It was shown that when the rise time of the voltage pulse is of 500 ns and the diffuse discharge occurs in the gap, the FWHM duration of the X-ray radiation pulse can reach ≈100 ns. It was established that at a pulse-periodic diffuse discharge fed by high-voltage pulses with the rise time of 50 ns, an energy of X-ray quanta and their number increase with increasing breakdown voltage. Wherein the parameter Um/pd is saved.

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