Influence of Ultrasonic Sealing Treatment with Aluminum Phosphate on Properties of Al2O3-TiO2 Plasma Sprayed Ceramic Coating

2021 ◽  
Author(s):  
Tuan Nguyen Van ◽  
Tuan Anh Nguyen ◽  
Phuong Nguyen Thi ◽  
Ha Pham Thi ◽  
Ly Pham Thi ◽  
...  
Keyword(s):  
Ceramic Coating ◽  
Erosion Resistance ◽  
Electrochemical Impedance ◽  
Aluminum Phosphate ◽  
Ceramic Coatings ◽  
Corrosion And Wear ◽  
Tio2 Ceramic ◽  
Plasma Sprayed ◽  
Sealing Treatment ◽  
Thermally Sprayed

Abstract Thermally sprayed Al2O3-TiO2 ceramic coatings provide exceptional hardness and corrosion and wear resistance, but the high velocities at which they are applied result in an inherently porous structure that requires some type of remediation. This study evaluates the effectiveness of ultrasonic aluminum phosphate sealing treatments on plasma sprayed Al2O3-40TiO2 ceramic coatings. The sealants were applied with and without ultrasonication (20-40 kHz) and were assessed using SEM/EDX analysis, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). Test data indicate that optimum sealing, corresponding to the highest values of corrosion protection and erosion resistance, are achieved under ultrasonication at 30 kHz for 5 hours.

Sealing Treatment of Plasma Sprayed Cr3C2-NiCr/Al2O3-TiO2 Coating by Aluminum Phosphate Sealant Containing Al2O3 Nanoparticles

2021 ◽  
Author(s):  
Tuan Nguyen Van ◽  
Tuan Anh Nguyen ◽  
Ha Pham Thi ◽  
Ly Pham Thi ◽  
Phuong Nguyen ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Electrochemical Impedance ◽  
Aluminum Phosphate ◽  
Al2o3 Nanoparticles ◽  
Treatment Efficiency ◽  
Typical Structure ◽  
Sprayed Coating ◽  
Plasma Sprayed ◽  
Sealing Treatment ◽  
Sprayed Coatings

Abstract A typical structure of thermal spray coatings consisted of molten particles, semi-molten particles, oxides, pores and cracks. These factors caused the porosity of sprayed coatings, leading to a great influence on the coating properties, especially their wear-corrosion resistance. In this study, a post-spray sealing treatment of Cr3C2-NiCr/Al2O3-TiO2 plasma sprayed coatings was carried out, then their corrosion properties were evaluated, before and after the treatment. For sealing process, aluminum phosphate (APP) containing aluminum oxide (Al2O3) nanoparticles (~10 nm) was used. The permeability of APP into the sprayed coating was analyzed by scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS). The treatment efficiency for porosity and corrosion resistance of sprayed coatings were evaluated by electrochemical measurements, such as the potentiodynamic polarization and electrochemical impedance spectroscopy. In addition, the wear-corrosion resistance of the sealed coating was examined in 3.5 wt.% NaCl circulation solution containing 0.25 wt.% SiO2 particles. The obtained results showed that APP penetrated deeply through the sprayed coating. The incorporation of Al2O3 nanoparticles into APP sealant enhanced the treatment efficiency of porosity for sprayed coating. The effect of the post-treatment on corrosion protection of the sprayed coating has been discussed.

Influence of Surface Microstructure of Ceramic Coatings on the Initiation and Development of Scuffing Phenomena

1998 ◽  
Author(s):  
B. Antoszewski ◽  
W. Zorawski
Keyword(s):  
Friction Force ◽  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Surface Microstructure ◽  
Frictional Pair ◽  
Plasma Sprayed ◽  
Thermally Sprayed

Abstract This paper deals with findings of experiments concerning the scuffing phenomenon in case the frictional pair is embodying an element with a thermally sprayed ceramic coating. The progress of building up of seizure is related and evaluated for a set of ceramic coatings embodying a diversity of granulations of Al2O3TiO2 and Cr2O3 plasma sprayed on steel, the IHI8N9T steel and carbon-graphite when tested on a roller-block machine. The greatest antiscuffing resistance was recorded for Cr2O3/carbon-graphite pair. An analysis of regression approximating friction force was carried through.

Interaction of a Crack in the Plasma-Sprayed Ceramic Coating with the Metal Substrate

2005 ◽  
Vol 482 ◽  
pp. 223-226
Author(s):  
Luboš Náhlík ◽  
Zdeněk Knésl ◽  
F. Kroupa
Keyword(s):  
Fracture Toughness ◽  
Fracture Mechanics ◽  
Surface Crack ◽  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Metal Substrate ◽  
High Density ◽  
Initial Surface ◽  
Young’S Moduli ◽  
Plasma Sprayed

Plasma-sprayed ceramic coatings contain a high density of intrasplat microcracks which are responsible for small Young’s moduli and low fracture toughness. The extension of an initial surface crack in the direction to the interface, where the crack is repelled by the metal substrate with higher Young’s modulus, is studied using the methods of fracture mechanics. It is shown that high tensile stresses induced by the crack in the interface can lead to a local decohesion along the interface so that the crack can deviate into the interface.

Thermal Barrier Effects Comparison of Plasma-Sprayed and Laser-Remelted Al2O3-13 % TiO2 Ceramic Coatings

2014 ◽  
Vol 978 ◽  
pp. 40-43
Author(s):  
Dong Sheng Wang ◽  
Guang Qu ◽  
Jin Lan Su
Keyword(s):  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Nanostructured Coating ◽  
Thermal Barrier ◽  
Heat Current ◽  
Barrier Effect ◽  
Laser Remelting ◽  
Plasma Sprayed ◽  
Sprayed Coatings ◽  
Conventional Coating

Conventional and nanosturctured Al2O3–13 wt% TiO2ceramic coatings were deposited by plasma spraying on TiAl alloy surface. Laser remelting experiment on as-sprayed coatings was carried out and the influences of laser remelting on microstructure and thermal barrier effect of the coating were researched. The results show that the as-sprayed conventional coating has a typical plasma-sprayed lamellar-like structure, while the nanostructured coating consisted of both fully melted regions and partially melted regions. The laser-remelted conventional coating exhibits column-like crystals which grew along the direction of the heat current, while the nanostructured coating composed of fine equiaxed grains with some remained nanoparticles. The nanostructured ceramic coating has higher thermal barrier effect than the conventional ceramic coating does. The thermal barrier effect of the as-sprayed coatings decreases after laser remelting.

The Weibull Distribution of Microhardness in Plasma Sprayed NiCrAl/AT13 Nanostructured Ceramic Coating

2013 ◽  
Vol 321-324 ◽  
pp. 318-323
Author(s):  
Gao Xu Tan ◽  
Tong Wang ◽  
En Bing Bi
Keyword(s):  
Weibull Distribution ◽  
Ceramic Coating ◽  
Ceramic Coatings ◽  
Tem Analysis ◽  
Average Value ◽  
Nanostructured Ceramic ◽  
Microhardness And Microstructure ◽  
Size Of Particles ◽  
Plasma Sprayed ◽  
The Relationship

Al2O3-13% TiO2 based nanostructured ceramic coatings were prepared on the surface of NiCrAl alloy by Plasma Spraying technology. Compared to the micron ceramic coating (MCC), the average value of hardness of nanostructured ceramic coating (NCC) was much higher than that of MCC, and the NCC presents typical bi-modal distribution. The Weibull distribution of both coatings exhibited apparently dispersible, but NCCs was quite well-distributed. The relationship between microhardness and microstructure were analyzed through SEM, XRD and TEM. The results indicate that the microcracks of NCC are fine and the size of particles is small. The structure of NCC coatings contained more α-Al2O3 and TiO2 and less γ-Al2O3 than that of MCC coatings. According to TEM analysis, it can be considered that the grain refinement, toughening of microcracks, and the dispersive refinement of Al2O3 nanoparticles on Al2O3-TiO2 matrix are main mechanisms to improve the mechanical properties of NCC.

scholarly journals Strain Isolated Ceramic Coatings

1983 ◽  
Author(s):  
R. P. Tolokan ◽  
J. B. Brady ◽  
G. P. Jarrabet
Keyword(s):  
Ceramic Coating ◽  
Combustion Engine ◽  
Ceramic Coatings ◽  
Thermal Barrier ◽  
Turbine Engine ◽  
Shock Testing ◽  
Low Modulus ◽  
Metal Strain ◽  
Fiber Metal ◽  
Plasma Sprayed

The durability of thermally shocked high tempererature ceramic coatings on metal substrates can be dramatically improved using a fiber metal strain isolator between ceramic and metal. The fiber metal strain isolator is a compliant, porous and low modulus material which yields to control the stress on the ceramic coating during thermal cycling. Plasma sprayed strain isolated ceramic coatings .060” (1.5 mm) thick have shown excellent durability in thermal shock testing. The strain isolated ceramic coating is an excellent thermal barrier since both the ceramic and fiber metal are good insulators. Applications include ceramic thermal barrier coatings for gas turbine engine seals and turbine components, combustors, MHD electrodes, and internal combustion engine insulation.

High Quality Ceramic Coatings Sprayed by High Efficiency Hypersonic Plasma Spraying Gun

2005 ◽  
Vol 475-479 ◽  
pp. 3981-3984 ◽  
Author(s):  
Sheng Zhu ◽  
Bin Shi Xu ◽  
Jiu Kun Yao
Keyword(s):  
Plasma Spraying ◽  
Ceramic Coating ◽  
High Efficiency ◽  
Low Cost ◽  
Ceramic Coatings ◽  
Air Plasma ◽  
Air Plasma Spraying ◽  
Ceramic Powders ◽  
Tio2 Ceramic ◽  
Spraying Process

This paper introduced the structure of the high efficiency hypersonic plasma spraying gun and the effects of hypersonic plasma jet on the sprayed particles. The optimised spraying process parameters for several ceramic powders such as Al2O3, Cr2O3, ZrO2, Cr3C2 and Co-WC were listed. The properties and microstructure of the sprayed ceramic coatings were investigated. Nano Al2O3-TiO2 ceramic coating sprayed by using the high efficiency hypersonic plasma spraying was also studied. Compared with the conventional air plasma spraying, high efficiency hypersonic plasma spraying improves greatly the ceramic coatings quality but at low cost.

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