Plasma Sprayed Alumina-Titania Coatings

1992 ◽  
Vol 271 ◽  
Author(s):  
T. J. Steeper ◽  
A. J. Rotolico ◽  
J. E. Nerz ◽  
W. L. Riggs ◽  
D. J. Varacalle ◽  
...  
Keyword(s):  
Dielectric Strength ◽  
Deposition Efficiency ◽  
Hydraulic Testing ◽  
Fractional Factorial ◽  
Operating Parameters ◽  
Spray Parameters ◽  
Air Plasma ◽  
X Ray Diffraction ◽  
Plasma Sprayed ◽  
Titania Coatings

ABSTRACTThis paper presents an experimental study of the air plasma spraying (APS) of alumina-titania powder using argon-hydrogen working gases. This powder system is being used in the fabrication of heater tubes that emulate nuclear fuel tubes for use in thermal-hydraulic testing. Experiments were conducted using a Taguchi fractional-factorial design parametric study. Operating parameters were varied around the typical spray parameters in a systematic design of experiments in order to display the range of plasma processing conditions and their effect on the resultant coatings. The coatings were characterized by hardness and electrical tests, surface profilometry, image analysis, optical metallography, and x-ray diffraction. Coating qualities are discussed with respect to dielectric strength, hardness, porosity, surface roughness, deposition efficiency, and microstructure. Attempts are made to correlate the features of the coatings with the changes in operating parameters.

Investigation of Changes in Microstructure of Remelted Air Plasma Sprayed NiCrAlY Coating after Short Thermal Exposure in Air with the Assistance of Microhardness Measurements

2013 ◽  
Vol 586 ◽  
pp. 226-229
Author(s):  
Veronika Řičánková ◽  
Ladislav Čelko ◽  
Jiří Švejcar
Keyword(s):  
Substrate Surface ◽  
Thermal Exposure ◽  
Ambient Atmosphere ◽  
Air Plasma ◽  
X Ray Diffraction ◽  
Nickel Based Superalloy ◽  
Nicraly Coating ◽  
Before And After ◽  
Coating Microstructure ◽  
Plasma Sprayed

The specimens in the present study were prepared by air plasma spraying of NiCrAlY coatings onto the INCONEL 713LC nickel-based superalloy substrate surface. Subsequently an aluminium sheet was cladded onto the coating surface by means of uniaxial cold pressing. After that the specimens were annealed at temperatures of 650, 850 and 1000°C for two hours in argon-flow atmosphere. The remelted NiCrAlY coating specimens were annealed at a temperature of 800°C for fifty hours in ambient atmosphere. A scanning electron microscope was used to record the changes in the modified coating microstructure. Chemical composition was measured by means of energy dispersive microanalysis. Qualitative and quantitative x-ray diffraction analysis was used for the final determination of phases. The microhardness of remelted air-plasma-sprayed NiCrAlY coatings before and after short thermal exposure was also measured.

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.

In-Flight Particle Characteristics of Plasma-Sprayed Dense Yttria Stabilized Zirconia

1998 ◽  
Author(s):  
L. Leblanc ◽  
C. Moreau
Keyword(s):  
Monitoring System ◽  
Particle Temperature ◽  
Deposition Efficiency ◽  
The State ◽  
Spray Parameters ◽  
Zirconia Powder ◽  
Integrated Optical ◽  
Coating Characteristics ◽  
Coating Microstructure ◽  
Plasma Sprayed

Abstract The influence of input spray parameters on the state of plasma-sprayed zirconia powder is studied. The particle temperature, velocity and diameter are measured using an integrated optical monitoring system. The monitoring system allows the investigation of the particles behavior in the spray jet. The collected information is correlated to coating characteristics such as deposition efficiency, microstructure and thermal diffusivity. Results show that, by monitoring the state of sprayed particles, a better understanding of the coating microstructure and properties can be achieved.

Effect of H2 on Microstructure and Property of Nano-Titania Coatings

2005 ◽  
Vol 486-487 ◽  
pp. 73-76
Author(s):  
Xiao Bing Zhao ◽  
Xuan Yong Liu ◽  
Chuan Xian Ding
Keyword(s):  
Methylene Blue ◽  
Water Solution ◽  
Atmospheric Plasma ◽  
Spray Parameters ◽  
X Ray Diffraction ◽  
Properties Of Coatings ◽  
Spraying Parameters ◽  
Ultraviolet Illumination ◽  
Methylene Blue Test ◽  
Titania Coatings

Nanostructured titania coatings were prepared by atmospheric plasma spraying using commercial nano-powder. The effects of plasma forming gas H2 on microstructure and anatase content of coatings were examined by X-ray diffraction and field emission scanning electron microscopy. Photocatalytic properties of coatings were evaluated through a photo degradation of methylene blue in water solution under ultraviolet illumination. The results obtained indicated that the TiO2 coating was a mixture of anatase and rutile. The anatase content of coatings increased with increase in the flow rate of plasma forming gas H2. The content of anatase was as high as 60% in the as-sprayed coatings under optimal spray parameters. The photocatalystic property was improved by the content of anatase in coatings. It was found that all fabricated TiO2 coatings exhibited photocatalytic activity for the methylene blue test regardless of spraying parameters.

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.

The Role of Different Atmospheric Plasma Spray Parameters on Microstructure of Abradable AlSi-Polyester Coatings

2017 ◽  
Vol 270 ◽  
pp. 224-229
Author(s):  
David Jech ◽  
Ladislav Čelko ◽  
Pavel Komarov ◽  
Jindřich Ziegelheim ◽  
Zdeněk Česánek ◽  
...  
Keyword(s):  
Deposition Efficiency ◽  
Atmospheric Plasma ◽  
Spray Parameters ◽  
Technological Parameters ◽  
Coating Microstructure ◽  
Two Parameters ◽  
Plasma Sprayed ◽  
Abradable Coatings ◽  
And Control

One of the approaches to increase the thermic efficiency of aerospace engines is the application of abradable coatings enabling minimization and control of the clearance between the stator and the rotating blades tips. The main purpose of this contribution is to define the role of different technological parameters utilized for atmospheric plasma spraying of AlSi-polyester coating on its resulting microstructure. Deposition of abradable coatings on the real engine parts is mostly dependent on spraying stand-off distance and on spraying angle. These two parameters influence not only the coating microstructure but also the deposition efficiency itself, which is directly connected with economical aspects of the coating production. The set of experimental samples with atmospheric plasma sprayed Ni-based bond coat and two in chemical composition same initial powders delivered from different powder manufacturers were used to spray thick AlSi-polymer top coats with different spraying stand-off distances and angles. Subsequently some of the samples were also heat treated to burn-out the polymer phase from the coating microstructure. The Rockwell HR15Y hardness was measured on all samples and the microstructure and coating thickness were evaluated by means of light microscopy and image analysis methods.

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.

Plasma Spraying of Zirconia Coatings

1989 ◽  
Vol 155 ◽  
Author(s):  
D. J. Varacalle ◽  
G. R. Smolik ◽  
G. C. Wilson ◽  
G. Irons ◽  
J. A. Walter
Keyword(s):  
Gas Flow ◽  
Analytical Study ◽  
Numerical Models ◽  
Fractional Factorial ◽  
Spray Parameters ◽  
X Ray Diffraction ◽  
Physical Processes ◽  
Particle Injection ◽  
Carrier Gas Flow ◽  
Temperature And Flow Fields

ABSTRACTAs part of an investigation of the dynamics that occur in the plume of a thermal spray torch, an experimental and analytical study of the deposition of yttria-stabilized zirconia has been accomplished. Experiments were conducted using a Taguchi fractional factorial design. Nominal spray parameters were: 900 A, 36 kW, 100 scfh argon primary gas flow, 47 scfh helium secondary gas flow, 11.5 scfh argon powder carrier gas flow, 3.5 lb/h powder feed rate, 3 in. spray distance, and an automated traverse rate of 20 in./s. The coatings were characterized for thickness, hardness, and microstructural features with optical microscopy, scanning electron microscopy, and x-ray diffraction. Attempts are made to correlate the features of the coatings with the changes in operating parameters. Numerical models of the physical processes in the torch column and plume were used to determine the temperature and flow fields. Computer simulations of particle injection (10 to 75 μm zirconia particles) are presented.

scholarly journals Effect of Shroud in Plasma Spraying on Chemical Composition and Thickness of Titanium Coatings

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 446
Author(s):  
Hong Zhou ◽  
Cheng Peng
Keyword(s):  
Chemical Composition ◽  
Plasma Spraying ◽  
Air Entrainment ◽  
Deposition Efficiency ◽  
Quantitative Chemical Analysis ◽  
Air Plasma ◽  
Lower Oxygen ◽  
Titanium Coatings ◽  
Plasma Sprayed ◽  
Steel Substrates

Titanium and its alloys are wildly used in industries. Shrouded plasma spray can be considered as a useful technology to produce low oxide containing titanium coatings. In this paper, the effect of shroud in plasma spraying on chemical composition and thickness of titanium coatings were investigated. Shrouded plasma-sprayed titanium coatings were deposited onto mild steel substrates. Air plasma-sprayed titanium coatings were also deposited for comparison under the same spraying parameters. Those titanium coatings were then studied in terms of microstructure, oxygen and nitrogen contents and coating’s thickness. The titanium coatings were assessed by scanning electron microscopy and quantitative chemical analysis. The results showed that the shroud played a key role in protecting the particles from oxidation in flight. The shrouded titanium coatings exhibited lower oxygen content and an enhanced microstructure. The reduction in air entrainment with the shroud resulted in better heating of the particles and increases in deposition efficiency and coating thickness.

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