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.

EFFECT OF OXYACETYLENE FLAME REMELTING ON WEAR BEHAVIOUR OF SUPERSONIC AIR-PLASMA SPRAYED NiCrBSi/h-BN COMPOSITE COATINGS

2016 ◽  
Vol 24 (06) ◽  
pp. 1750083 ◽  
Author(s):  
N. N. ZHANG ◽  
D. Y. LIN ◽  
B. HE ◽  
G. W. ZHANG ◽  
Y. ZHANG ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Composite Coatings ◽  
Alloy Coating ◽  
Wear Behaviour ◽  
Air Plasma ◽  
X Ray ◽  
Wear And Corrosion ◽  
Before And After ◽  
Higher Temperature ◽  
Plasma Sprayed

NiCrBSi alloy coatings are widely used in wear and corrosion protection at higher temperature. As a primary hard phase forming element, B element can effectively improve the coating hardness. In this study, the low coefficient of friction of BN with three ratios (10%, 20%, and 30%) was added in order to reduce the wear rate and provide additional B element. The NiCrBSi/h-BN composite coatings were successfully prepared on a cast-iron substrate using supersonic air-plasma spray technology. The phase constitution, microstructure characterization, and microhardness of the coatings before and after oxyacetylene flame remelting were investigated by means of scanning electron microscope (SEM), X-ray diffraction, and energy dispersive analysis of X-ray techniques, respectively. The wear resistance of composite coatings was also tested in this paper. It was found that the microstructure was well refined by remelting treatment and this was beneficial for the adherence between the coating and the substrate, which was nearly 33[Formula: see text]MPa. The wear resistance of the NiCrBSi alloy coating was also improved with the increasing component of h-BN in remelted samples. When the h-BN content reached 30%, the friction coefficient decreased to 0.38 for the remelted coating. The effect of the remelting process on the anti-abrasive property and extension of the material’s wear life was quite important.

scholarly journals Composition versus Wear Behaviour of Air Plasma Sprayed NiCr–TiB2–ZrB2 Composite Coating

Coatings ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 273
Author(s):  
Ning Zhang ◽  
Nannan Zhang ◽  
Sheng Guan ◽  
Shumei Li ◽  
Guangwei Zhang ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Composite Coating ◽  
High Hardness ◽  
High Energy ◽  
Wear Behaviour ◽  
Air Plasma ◽  
X Ray Diffraction ◽  
X Ray ◽  
Energy Ball ◽  
Plasma Sprayed

The NiCr–TiB2–ZrB2 composite coating was deposited on the surface of blades made of steel (SUS304) using high-energy ball milling technology and air plasma spraying technology, which aimed to relieve the wear of the blades during operation. The influence of titanium diboride (TiB2) and zirconium diboride (ZrB2) on the microstructure and wear resistance of the coatings was investigated by X-ray diffraction, scanning electron microscopy, Vickers microhardness tester, and a wear tester. The results showed that the TiB2 and ZrB2 particles were unevenly distributed in the coatings and significantly increased the hardness and anti-wear, which contributed to their ultra-high hardness and extremely strong ability to resist deformation. The performance of the coatings was improved with the increase of the number of ceramic phases, while the hardness and wear resistance of the coating could reach their highest value when the TiB2 and ZrB2 respectively took up 15 wt.% of the total mass of the powder.

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.

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.

Effect of Heat Treatment on Structure and Phase Transformation of Rare Earth (Gd) Zirconate

2010 ◽  
Vol 163 ◽  
pp. 157-160 ◽  
Author(s):  
Grzegorz Moskal ◽  
Grzegorz Dercz
Keyword(s):  
Phase Transformation ◽  
Spherical Shape ◽  
Air Plasma ◽  
X Ray Diffraction ◽  
Cross Sectional ◽  
X Ray ◽  
Barrier Coating ◽  
Profile Fitting ◽  
Powder Particles ◽  
Plasma Sprayed

In the present work, zirconium gadolinium oxide (Gd2Zr2O7) ceramics were prepared by annealing in different conditions and with APS (air plasma sprayed) techniques for thermal barrier coating (TBC) application. Thermal properties, phase transformation, crystal structure and cross-sectional morphologies of these materials were investigated. The thermal behaviour of the material was investigated from room temperature to 1500°C using the differential thermal analysis (DTA). The X-ray diffraction methods were used for the qualitative phase analysis. The structure of the studied samples has been characterized by employing powerful Rietveld’s whole X-ray profile fitting technique using the DBWS 9807a program. The SEM and EDS techniques were used to in the ceramic samples morphology analysis and for their chemical composition, respectively. The research showed that further stages of annealing result in the phase transformation of the parent substances and the main phase Gd2Zr2O7. It was found out that complete phase transformation into Gd2Zr2O7 phase takes place only for the air plasma sprayed sample. The analysis of the morphology of the initial powder revealed the spherical shape of the powder particles, which have a porous internal structure.

Structure and Electrochemical Behavior of Plasma-Sprayed LSGM Electrolyte Films

2002 ◽  
Vol 756 ◽  
Author(s):  
H. Zhang ◽  
X. Ma ◽  
J. Dai ◽  
S. Hui ◽  
J. Roth ◽  
...  
Keyword(s):  
Electrochemical Behavior ◽  
Electrochemical Impedance ◽  
Amorphous Structure ◽  
Solid Oxide ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spray Process ◽  
Plasma Spray Process ◽  
Electrolyte Film ◽  
Plasma Sprayed

ABSTRACTAn intermediate temperature solid oxide fuel cell (SOFC) electrolyte film of La0.8Sr 0.2Ga0.8Mg0.2O2.8 (LSGM) was fabricated using a plasma spray process. The microstructure and phase were investigated using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The electrochemical behavior of the thermal sprayed LSGM film was investigated using electrochemical impedance spectroscopy (EIS). The study indicates that thermal spray can deposit a dense LSGM layer. It was found that the rapid cooling in the thermal process led to an amorphous or poor crystalline LSGM deposited layer. This amorphous structure has a significant effect on the performance of the cell. Crystallization of the deposited LSGM layer was observed during annealing between 500–600 °C. After annealing at 800 °C, the ionic conductivity of the sprayed LSGM layer can reach the same level as that of the sintered LSGM.

Phase Evolution upon Aging of Air-Plasma Sprayedt′-Zirconia Coatings: I-Synchrotron X-Ray Diffraction

2012 ◽  
Vol 96 (1) ◽  
pp. 290-298 ◽  
Author(s):  
Don M. Lipkin ◽  
Jessica A. Krogstad ◽  
Yan Gao ◽  
Curtis A. Johnson ◽  
Warren A. Nelson ◽  
...  
Keyword(s):  
Phase Evolution ◽  
Air Plasma ◽  
X Ray Diffraction ◽  
X Ray

scholarly journals Effect of Graphene Oxide Concentration in Electrolyte on Corrosion Behavior of Electrodeposited Zn–Electrochemical Reduction Graphene Composite Coatings

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 758 ◽  
Author(s):  
Yang ◽  
Zhang ◽  
Wang ◽  
Wang ◽  
Chen ◽  
...  
Keyword(s):  
Corrosion Behavior ◽  
Electrochemical Impedance ◽  
Composite Coatings ◽  
Laser Raman Spectroscopy ◽  
304 Stainless Steel ◽  
Sulfate Electrolyte ◽  
X Ray Diffraction ◽  
X Ray ◽  
Tafel Polarization ◽  
Laser Raman

Pure Zn and Zn–ERGO composite coatings were prepared by direct current electrodeposition on 304 stainless steel. Samples were characterized by X-ray diffraction (XRD), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM/EDS), and laser Raman spectroscopy (Raman). Results obtained have shown that the concentration of GO sheets in zinc sulfate electrolyte has an important effect on the preferred crystal orientation and the surface morphology of Zn–ERGO composite coatings. A study of the corrosion behavior of the coatings by Tafel polarization and electrochemical impedance spectroscopic (EIS) methods leads to the conclusion that the Zn-1.0 g/L ERGO composite coating possesses the best corrosion resistance compared to the pure Zn coating and other composite coatings in this study.

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