Characterization of Plasma Sprayed Yittria Stabilized Zirconia (8 wt %) Hydroxyapatite Coatings

2011 ◽  
Vol 493-494 ◽  
pp. 535-538
Author(s):  
O. Anzabi ◽  
M.M. Aydin ◽  
L.S. Ozyegin ◽  
F.N. Oktar ◽  
Kārlis A. Gross ◽  
...  
Keyword(s):  
Titanium Oxide ◽  
Pure Titanium ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
X Ray ◽  
Bond Coatings ◽  
Bond Coating ◽  
Bond Layer ◽  
Diffraction Patterns ◽  
Plasma Sprayed

Splitting problems at HA-coated implants are generally due to biological reasons. Bond-coatings were used to prevent the splitting problem of zirconia ceramics; this method can be widely seen in industrial applications. Two main groups were used; the first group consisted of spraying a bond layer of titania onto commercially pure titanium. This followed by a spray of HA with 5, 10 and 15 % zirconia (8 % yttria doped) as main layer onto the first bond-coating. For the second group, the samples were coated without bond-coating. Firstly, X-ray diffraction patterns of the starting powders were taken. Then x-ray diffraction patterns of the plasma sprayed samples were taken. In literature, it was seen that 20 % zirconia was sufficient for the transformation into a monoclinic structure for the bond-coated samples. For this study it was found that 10 % zirconia was sufficient to transform to the same structure of the desired crystalline phase transformation. The coating kept its crystal structure and relatively small amount of amorphous transformation was detected. A similar structure was produced using less zirconia. It was thought that the use of titanium-oxide bond-coating layer would play an important role as a third variable in the results. To further investigate these phenomena, more detailed researches must be conducted with using titanium-oxide yittria stabilized zirconia (8 wt %) hydroxyapatite bond-coatings with HA main coatings.

MICROSTRUCTURE OF PLASMA-SPRAYED Al2O3–ZrO2 COMPOSITE COATINGS

2006 ◽  
Vol 13 (05) ◽  
pp. 545-549 ◽  
Author(s):  
LUBIN CHEN ◽  
CHUANZHONG CHEN ◽  
LIANG ZHANG ◽  
BIAO QI ◽  
TING-QUAN LEI
Keyword(s):  
Composite Coatings ◽  
Spray Coating ◽  
Air Plasma ◽  
Air Plasma Spraying ◽  
X Ray Diffraction ◽  
Layer System ◽  
X Ray ◽  
Bond State ◽  
Bond Layer ◽  
Plasma Sprayed

Thermal barrier coatings of Al 2 O 3– ZrO 2 were prepared by air plasma spraying on the surface of 20G steel. Phase constitution, microstructures and elemental distributions of the coatings were studied by X-ray diffraction, scanning electron microscope and electron probe X-ray microanalysis. The results show that the plasma spray coating mainly consists of α- Al 2 O 3, c - ZrO 2, and t - ZrO 2. The bond state of the interface between the top layer and bond layer is fine, and the bond layer has a good combination with the substrate. ZrO 2 and Al 2 O 3 structures can closely integrate together and form compact top layer system.

Neutron and X-ray diffuse scattering of calcium-stabilized zirconia

1996 ◽  
Vol 52 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Th. Proffen ◽  
R. B. Neder ◽  
F. Frey
Keyword(s):  
Oxygen Vacancy ◽  
Defect Structure ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Single Vacancy ◽  
Modified Model ◽  
X Ray ◽  
Diffraction Patterns ◽  
Single Oxygen ◽  
Good Agreement

The defect structure of calcium-stabilized zirconia (CSZ) is described in terms of a correlated distribution of microdomains within the cubic matrix of CSZ. The defect structure consists of two types of defects: microdomains based on a single oxygen vacancy with relaxed neighbouring ions and microdomains based on a pair of oxygen vacancies separated by 3 1/2/2a along <111>. The combined evaluation of neutron and X-ray data shows that the previously published structure of the single vacancy domain has to be modified: All cations next to the oxygen vacancy are most likely zirconium. This modified model leads to good agreement between observed and calculated neutron and X-ray diffraction patterns.

scholarly journals A synchrotron X-ray diffraction deconvolution method for the measurement of residual stress in thermal barrier coatings as a function of depth

2016 ◽  
Vol 49 (6) ◽  
pp. 1904-1911 ◽  
Author(s):  
C. Li ◽  
S. D. M. Jacques ◽  
Y. Chen ◽  
D. Daisenberger ◽  
P. Xiao ◽  
...  
Keyword(s):  
Residual Stress ◽  
Thermal Barrier ◽  
Stress Profile ◽  
Air Plasma ◽  
X Ray Diffraction ◽  
X Ray ◽  
Barrier Coating ◽  
Average Residual ◽  
Diffraction Patterns ◽  
Plasma Sprayed

The average residual stress distribution as a function of depth in an air plasma-sprayed yttria stabilized zirconia top coat used in thermal barrier coating (TBC) systems was measured using synchrotron radiation X-ray diffraction in reflection geometry on station I15 at Diamond Light Source, UK, employing a series of incidence angles. The stress values were calculated from data deconvoluted from diffraction patterns collected at increasing depths. The stress was found to be compressive through the thickness of the TBC and a fluctuation in the trend of the stress profile was indicated in some samples. Typically this fluctuation was observed to increase from the surface to the middle of the coating, decrease a little and then increase again towards the interface. The stress at the interface region was observed to be around 300 MPa, which agrees well with the reported values. The trend of the observed residual stress was found to be related to the crack distribution in the samples, in particular a large crack propagating from the middle of the coating. The method shows promise for the development of a nondestructive test for as-manufactured samples.

The Effects of Composition and Sintering Conditions on Zirconia Toughened Alumina (ZTA) Nanocomposites

2010 ◽  
Vol 93-94 ◽  
pp. 695-698 ◽  
Author(s):  
H. Esfahani ◽  
Ali Nemati ◽  
E. Salahi
Keyword(s):  
Tetragonal Zirconia ◽  
Al2o3 Nanoparticles ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Constant Composition ◽  
X Ray ◽  
Different Temperatures ◽  
Lattice Network ◽  
Diffraction Patterns ◽  
Zirconia Toughened Alumina

Zirconia Toughened Alumina (ZTA) Nanocomposites were prepared using Nano sized Zirconia (ZrO2) powders doped with 3% mol of yttria (Y2O3) nanopowders. Diffusion of α-alumina (Al2O3) nanoparticles as well as yttria into the Zirconia lattice network drives monoclinic – tetragonal martensitic transformation. Zirconia toughened alumina (ZTA) composites containing different amount of partially stabilized Zirconia (PSZ) 5, 10, 15 and 20% mol, were prepared via wet mixing and axial pressing. After sintering at different temperatures,1450, 1550 and 1650 °C, phase change in the samples were monitored. X-ray diffraction patterns showed that at constant composition, tetragonal zirconia was increased by temperature increasing due to intensification of diffuse coefficient of alumina and yttria in the system. At constant temperature, remained monoclinic zirconia was increased with Zirconia content increasing.

Studies on diffusion maximum in x-ray diffraction patterns of plasma-sprayed hydroxyapatite coatings

1998 ◽  
Vol 40 (3) ◽  
pp. 407-413 ◽  
Author(s):  
Weidong Tong ◽  
Zongjian Yang ◽  
Xingdong Zhang ◽  
Aiping Yang ◽  
Jiaming Feng ◽  
...  
Keyword(s):  
X Ray Diffraction ◽  
X Ray ◽  
Hydroxyapatite Coatings ◽  
Diffraction Patterns ◽  
Plasma Sprayed

Nano-SiC Modified Plasma Sprayed Ceramic Coatings Prepared by Laser Sintering

2008 ◽  
Vol 375-376 ◽  
pp. 348-352 ◽  
Author(s):  
Zong Jun Tian ◽  
Li Da Shen ◽  
Yin Hui Huang ◽  
Guo Ran Hua
Keyword(s):  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Laser Sintering ◽  
Laser Remelting ◽  
X Ray Diffraction ◽  
X Ray ◽  
Bond Coating ◽  
Plasma Sprayed ◽  
Steel Substrates ◽  
Electronic Microscope

This paper describes an investigation of nano-SiC reinforced ceramic coating, which has included NiCrAl and Al2O3+13wt%TiO2 coatings pre-produced by atmosphere plasma spraying, implemented by laser sintering. Commercial NiCrAl powders were plasma sprayed onto 45 steel substrates to produce a bond coating with thickness of ~100μm. The Al2O3-TiO2 based coating with ~500μm thickness was then plasma sprayed on top of the NiCrAl bond coating. With CO2 laser, nano-SiC powders were laser sintered on Al2O3-TiO2 based coatings. The microstructure and chemical composition of the modified based coatings were analyzed by such detection devices as scanning electronic microscope (SEM) and x-ray diffraction (XRD). The results show that the size of SiC grains has no obvious growth. In addition, due to the nanostructured SiC phase and laser remelting, the modified coatings exhibited better abrasion resistance than those unmodified samples.

Evaluation of Freezing Methods by Low Temperature X-Ray Diffraction

1977 ◽  
Vol 35 ◽  
pp. 330-333
Author(s):  
T. Gulik-Krzywicki ◽  
M.J. Costello
Keyword(s):  
Biological Materials ◽  
Molecular Organization ◽  
X Ray Diffraction ◽  
Glass Capillary ◽  
X Ray ◽  
Rate Dependent ◽  
Before And After ◽  
Freeze Etching ◽  
Diffraction Patterns ◽  
Set Up

Freeze-etching electron microscopy is currently one of the best methods for studying molecular organization of biological materials. Its application, however, is still limited by our imprecise knowledge about the perturbations of the original organization which may occur during quenching and fracturing of the samples and during the replication of fractured surfaces. Although it is well known that the preservation of the molecular organization of biological materials is critically dependent on the rate of freezing of the samples, little information is presently available concerning the nature and the extent of freezing-rate dependent perturbations of the original organizations. In order to obtain this information, we have developed a method based on the comparison of x-ray diffraction patterns of samples before and after freezing, prior to fracturing and replication.Our experimental set-up is shown in Fig. 1. The sample to be quenched is placed on its holder which is then mounted on a small metal holder (O) fixed on a glass capillary (p), whose position is controlled by a micromanipulator.

Examination of Rabbit Fc Crystals

1968 ◽  
Vol 26 ◽  
pp. 140-141
Author(s):  
J. P. Robinson ◽  
P. G. Lenhert
Keyword(s):  
Molecular Weight ◽  
Flat Plate ◽  
Phosphate Buffer ◽  
Asymmetric Unit ◽  
X Ray Diffraction ◽  
X Ray ◽  
Neutral Ph ◽  
Small Crystals ◽  
Carbon Coated ◽  
Diffraction Patterns

Crystallographic studies of rabbit Fc using X-ray diffraction patterns were recently reported. The unit cell constants were reported to be a = 69. 2 A°, b = 73. 1 A°, c = 60. 6 A°, B = 104° 30', space group P21, monoclinic, volume of asymmetric unit V = 148, 000 A°3. The molecular weight of the fragment was determined to be 55, 000 ± 2000 which is in agreement with earlier determinations by other methods.Fc crystals were formed in water or dilute phosphate buffer at neutral pH. The resulting crystal was a flat plate as previously described. Preparations of small crystals were negatively stained by mixing the suspension with equal volumes of 2% silicotungstate at neutral pH. A drop of the mixture was placed on a carbon coated grid and allowed to stand for a few minutes. The excess liquid was removed and the grid was immediately put in the microscope.

Control of the phase composition of advanced calcium phosphates using an x-ray diffractometer with a curved position-sensitive detector

2020 ◽  
Vol 86 (6) ◽  
pp. 29-35
Author(s):  
V. P. Sirotinkin ◽  
O. V. Baranov ◽  
A. Yu. Fedotov ◽  
S. M. Barinov
Keyword(s):  
Phase Composition ◽  
Calcium Phosphates ◽  
Position Sensitive Detector ◽  
Sensitive Detector ◽  
X Ray Diffraction ◽  
X Ray ◽  
Impurity Phases ◽  
Position Sensitive ◽  
Diffraction Peaks ◽  
Diffraction Patterns

The results of studying the phase composition of advanced calcium phosphates Ca10(PO4)6(OH)2, β-Ca3(PO4)2, α-Ca3(PO4)2, CaHPO4 · 2H2O, Ca8(HPO4)2(PO4)4 · 5H2O using an x-ray diffractometer with a curved position-sensitive detector are presented. Optimal experimental conditions (angular positions of the x-ray tube and detector, size of the slits, exposure time) were determined with allowance for possible formation of the impurity phases during synthesis. The construction features of diffractometers with a position-sensitive detector affecting the profile characteristics of x-ray diffraction peaks are considered. The composition for calibration of the diffractometer (a mixture of sodium acetate and yttrium oxide) was determined. Theoretical x-ray diffraction patterns for corresponding calcium phosphates are constructed on the basis of the literature data. These x-ray diffraction patterns were used to determine the phase composition of the advanced calcium phosphates. The features of advanced calcium phosphates, which should be taken into account during the phase analysis, are indicated. The powder of high-temperature form of tricalcium phosphate strongly adsorbs water from the environment. A strong texture is observed on the x-ray diffraction spectra of dicalcium phosphate dihydrate. A rather specific x-ray diffraction pattern of octacalcium phosphate pentahydrate revealed the only one strong peak at small angles. In all cases, significant deviations are observed for the recorded angular positions and relative intensity of the diffraction peaks. The results of the study of experimentally obtained mixtures of calcium phosphate are presented. It is shown that the graphic comparison of experimental x-ray diffraction spectra and pre-recorded spectra of the reference calcium phosphates and possible impurity phases is the most effective method. In this case, there is no need for calibration. When using this method, the total time for analysis of one sample is no more than 10 min.

Characterizations of Synthetic 8mol% YSZ with Comparison to 3mol %YSZ for HT-SOFC

2020 ◽  
Vol 38 (4A) ◽  
pp. 491-500
Author(s):  
Abeer F. Al-Attar ◽  
Saad B. H. Farid ◽  
Fadhil A. Hashim
Keyword(s):  
Ionic Conductivity ◽  
Electrochemical Impedance ◽  
Structural Information ◽  
Impedance Analysis ◽  
High Energy ◽  
Yttria Stabilized Zirconia ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Powder Morphology ◽  
X Ray

In this work, Yttria (Y2O3) was successfully doped into tetragonal 3mol% yttria stabilized Zirconia (3YSZ) by high energy-mechanical milling to synthesize 8mol% yttria stabilized Zirconia (8YSZ) used as an electrolyte for high temperature solid oxide fuel cells (HT-SOFC). This work aims to evaluate the densification and ionic conductivity of the sintered electrolytes at 1650°C. The bulk density was measured according to ASTM C373-17. The powder morphology and the microstructure of the sintered electrolytes were analyzed via Field Emission Scanning Electron Microscopy (FESEM). The chemical analysis was obtained with Energy-dispersive X-ray spectroscopy (EDS). Also, X-ray diffraction (XRD) was used to obtain structural information of the starting materials and the sintered electrolytes. The ionic conductivity was obtained through electrochemical impedance spectroscopy (EIS) in the air as a function of temperatures at a frequency range of 100(mHz)-100(kHz). It is found that the 3YSZ has a higher density than the 8YSZ. The impedance analysis showed that the ionic conductivity of the prepared 8YSZ at 800°C is0.906 (S.cm) and it was 0.214(S.cm) of the 3YSZ. Besides, 8YSZ has a lower activation energy 0.774(eV) than that of the 3YSZ 0.901(eV). Thus, the prepared 8YSZ can be nominated as an electrolyte for the HT-SOFC.

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