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 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 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.

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.

scholarly journals Phase composition of coatings on the D16 alloy during micro-arc oxdation in alkaline and silicate electrolytes

2020 ◽  
Vol 1,2020 (1,2020 (124)) ◽  
pp. 51-55
Author(s):  
Subbotina V ◽  
Belozerov V ◽  
Sobol’ O
Keyword(s):  
Phase Composition ◽  
Liquid Glass ◽  
Amorphous State ◽  
Practical Significance ◽  
Alkaline Electrolyte ◽  
X Ray ◽  
Micro Arc Oxidation ◽  
Coating Formation ◽  
Al2o3 Phase ◽  
Α Al2o3

Goal. The influence of electrolysis conditions at different electrolyte compositions on the phase formation of coatings obtained by micro-arc oxidation (MDO) on an aluminum alloy D16 was studied. Method. For electrolysis, two types of electrolytes were used: alkaline electrolyte (solution (KOH) in distilled water), silicate electrolyte (with different percentages of Na2SiO3 component). Research results. It was found that the phase composition of the MAO coatings obtained in an alkaline (KOH) electrolyte mainly consists of γ - Al2O3 phases and, to a much lesser extent, the α-Al2O3 phases. An increase in the KOH concentration leads to a shift in the γ – Al2O3 → α – Al2O3 polymorphic reaction toward the formation of the hardest α-Al2O3 phase (corundum). The formation of the preferred orientation of the growth of crystallites of γ – Al2O3 and α – Al2O3 phases during their formation in an alkaline electrolyte was not detected. Scientific novelty. A significant influence on the mechanism and processes of coating formation is made by the addition of liquid glass (Na2SiO3) in the electrolyte. In this case, the growth rate of the coating increases significantly, but the size of the ordering regions decreases from crystalline to X-ray amorphous. The phase composition of the MAO coatings, when they are formed in a silicate electrolyte, varies from a mixture of the γ - Al2O3 phase and mullite (3Al2O3 • 2SiO2) with a low content of liquid glass (10 g/l Na2SiO3) to the formation of only the X-ray amorphous phase with a high content of liquid glass in the electrolyte (50 g/l Na2SiO3). Practical significance. It was concluded that the use of an alkaline or silicate electrolyte with different percentages allows a wide variation of both the phase composition and structural state (α- Al2O3 and γ- Al2O3 phases, mullite (3Al2O3 • 2SiO2) or X-ray amorphous state) and the kinetics of growth the coating itself.

Influences of Calcination Ambiences on Morphologies, Phase Composition and Contents of the Elements of Ceramic Coatings on Ti Alloy by Micro-Arc Oxidation

2012 ◽  
Vol 512-515 ◽  
pp. 1066-1069
Author(s):  
Jin Xue Zhang
Keyword(s):  
Electron Microscopy ◽  
Phase Composition ◽  
Ceramic Coatings ◽  
Ti Alloy ◽  
X Ray ◽  
Micro Arc Oxidation ◽  
Oxidation Properties ◽  
Α Al2o3 ◽  
Scanning Electron

Compound ceramic coatings with the main crystal phase of Al2TiO5 (as-coated samples) were prepared in situ on the surface of Ti-6Al-4V alloy by means of pulsed bi-polar micro-arc oxidation (MAO) in an NaAlO2 solution. The coated samples were calcined in argon and air at 1000 oC, respectively. The phase composition, surface and section morphology, and element contents of the ceramic coatings were investigated by X-ray diffractometry (XRD), Scanning electron microscopy (SEM) and X-ray fluorescence spectroscopy (XRF). The samples were treated in argon and the as-coated ones were calcined in air at 1000 oC to study the anti-oxidation properties of the samples. The results show that Al2TiO5 had been decomposed in an hour and transformed into α-Al2O3 and rutile TiO2 in air. However, Al2TiO5 had been decomposed in four hours in argon and the final coating surface was completely composed of α-Al2O3. The content of Al2O3 was decreased from outside to inside layers and Ti2O3 was formed in the coating. Furthermore, the morphology of the ceramic coatings after the calcination was different. The coatings calcined in argon were finer; the grains and pores were smaller than those in air.

Effect of Lanthanum Nitrate on Titanium Alloys Ceramic Membrane Formed by Micro-Arc Oxidation

2013 ◽  
Vol 300-301 ◽  
pp. 1330-1333
Author(s):  
Shi Jie Li ◽  
Xiao Feng ◽  
Lu Ming Wang
Keyword(s):  
Biological Activity ◽  
Phase Composition ◽  
Titanium Alloys ◽  
Ceramic Membrane ◽  
Oxidation Process ◽  
Ceramic Membranes ◽  
Lanthanum Nitrate ◽  
Micro Arc Oxidation ◽  
Calcium And Phosphorus ◽  
Microscopic Surface

Titanium alloys ceramic membranes were prepared via micro-arc oxidation process in original electrolyte and in the electrolyte adding lanthanum nitrate respectively.The microscopic surface morphology,energy spectrum and phase composition were analysed.The biological activity was evaluated by soaking in simulated body fluid.The results indicate that lanthanum nitrate could improve the surface topography,make more calcium and phosphorus enter into the film and promote the generation of hydroxyapatite.

Sol-Gel Derived Biphasic HA/FA Coatings

2006 ◽  
Vol 309-311 ◽  
pp. 651-654
Author(s):  
Kui Cheng ◽  
Wen Jian Weng ◽  
Shun Dong Miao ◽  
Pi Yi Du ◽  
Ge Shen ◽  
...  
Keyword(s):  
Surface Morphology ◽  
Photoelectron Spectroscopy ◽  
Cell Attachment ◽  
Sol Gel ◽  
Dip Coating ◽  
Ethanol Solution ◽  
X Ray ◽  
Phosphate Coatings ◽  
Homogenous Distribution ◽  
Calcium Phosphate Coatings

In order to optimize the dissolution resistance, cell attachment and Ca and P releasing ability of the calcium phosphate coatings, Hydroxyapatite/fluorapatite (HA/FA) biphasic coatings are prepared and characterized. Ultrasonically dispersing of HA powders in the mixed ethanol solution of Ca(NO3)2, P2O5 and HPF6, to form a “colloidal sol” for dip coating. The coatings are prepared on Ti6Al4V substrate by dip coating, 150oC drying and 600oC firing. The coatings are characterized by X-ray Diffractometer for the crystalline phase, X-ray Photoelectron Spectroscopy for chemical composition and Scanning Electron Microscopy for the surface morphology. The results show biphasic HA/FA coatings with homogenous distribution of HA particle in the FA matrix can be obtained. The nominal F content of the coatings decreases with the increasing amount of HA, and the surface morphology is rough. These demonstrate the obtained biphasic HA/FA coatings are suitable to response to cells, accelerating bone formation.

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