Alumina-Titania Spot Spraying Bead Formation and Characteristics in Atmospheric Plasma Spraying

2007 ◽  
Vol 534-536 ◽  
pp. 401-404
Author(s):  
Hye Sook Joo ◽  
Han Shin Choi ◽  
Hyung Ho Jo ◽  
Hoon Cho ◽  
June Seob Kim ◽  
...  
Keyword(s):  
Deposition Rate ◽  
Mass Flux ◽  
Deposition Efficiency ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Gas Composition ◽  
Particle Segregation ◽  
Rate Maximum ◽  
The Moment ◽  
Short Time

Fine and coarse alumina-titania composite particles were overlaid by allowing the particles to be deposited for a short time without moving a plasmatron [spot spraying bead]. Both the deposition efficiency and maximum deposition rate were measured at the different plasma gas composition. Considering the normalized maximum deposition rate [(maximum deposition rate)x(deposition efficiency)-1], effects of particle size and plasma gas composition on the particle segregation within a cross-section of mass flux could be estimated. Also, particle melting state according to the position within a mass flux at the moment of impact could be also estimated through the investigations of microstructure and phase composition of the spot spraying bead.

Microstructure of Atmospheric Plasma Sprayed (Al,Cr)2O3-TiO2 Coatings from Blends

2021 ◽  
Author(s):  
Maximilian Grimm ◽  
Rico Drehmann ◽  
Thomas Lampke ◽  
Susan Conze ◽  
Lutz-Michael Berger
Keyword(s):  
Solid Solution ◽  
Plasma Spraying ◽  
Chromium Content ◽  
Defect Density ◽  
Deposition Efficiency ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Tio2 Content ◽  
Tio2 Coatings ◽  
Plasma Sprayed

Abstract This study investigates the microstructure and hardness of coatings produced by atmospheric plasma spraying using a commercial (Al,Cr)2O3 solid solution (ss) powder blended with various amounts of TiO2. The microstructures were analyzed using SEM, EDS, and XRD measurements. It was shown that blending with TiO2 reduces porosity and defect density while increasing deposition efficiency and microhardness. Small amounts of Ti in ss (Al,Cr)2O3 splats were detected in coatings prepared from blends with higher TiO2 content. Variations in aluminum and chromium content were also observed.

Effect of binary rare earth oxide on the properties of plasma sprayed Al2O3/TiO2 coatings

2017 ◽  
Vol 69 (5) ◽  
pp. 808-814
Author(s):  
Qingjun Ding ◽  
Bo Tian ◽  
Gai Zhao ◽  
Feng Wang ◽  
Huafeng Li ◽  
...  
Keyword(s):  
Rare Earth ◽  
Plasma Spraying ◽  
Adhesion Strength ◽  
Rare Earth Oxide ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Micro Hardness ◽  
Content Type ◽  
Melting Degree ◽  
Binary Rare Earth

Purpose This study systematically investigated the effect of the binary rare earth oxide of La2O3 and Sm2O3 on the properties of the Al2O3/TiO2 (AT) coating, including phase transform, wear behavior, etc. Design/methodology/approach AT coatings mixed with different components of binary rare earth oxides of La2O3 and Sm2O3 are prepared by atmospheric plasma spraying. The adhesion strength, micro-hardness, phase transition and tribological behavior of coatings are systematically investigated. Findings The X-ray diffraction (XRD) analysis shows that phase transformation is obvious after spraying, and a-Al2O3 is almost translated into γ-Al2O3 when La2O3 and Sm2O3 are doped together. Meanwhile, solid solution generated between rare earth oxide and Al2O3/TiO2 coatings results in disappearance of TiO2 and rare earth oxide phase. The photos under the scanning electron microscope (SEM) indicate that binary rare earth oxide could increase the melting degree of powder and decrease porosity of coatings.The increasing of Sm2O3 rarely affect micro-hardness and adhesion strength, and the coating with 4 per cent Sm2O3 and 1 per cent La2O3 exhibits the best wear resistance and lowest friction coefficient among all the samples. Originality/value AT coatings mixed with different components of binary rare earth oxide of La2O3 and Sm2O3 are prepared by atmospheric plasma spraying. Binary rare earth oxide could increase the melting degree of powder and decrease porosity of AT coatings.

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