scholarly journals High-Temperature Oxidation Properties of MCrAlY Coatings Formed by Atmospheric Plasma Spraying

2016 ◽  
Vol 65 (10) ◽  
pp. 700-705
Author(s):  
Tatsuo SUIDZU ◽  
Syun NISHIZAKO ◽  
Masayuki ARAI
Keyword(s):  
High Temperature ◽  
Plasma Spraying ◽  
High Temperature Oxidation ◽  
Atmospheric Plasma Spraying ◽  
Atmospheric Plasma ◽  
Temperature Oxidation ◽  
Mcraly Coatings ◽  
Oxidation Properties

Microstructure Characteristics and High-Temperature Oxidation Behavior of Plasma-Sprayed and Laser-Remelted MCrAlY Coatings on TiAl Intermetallics

2011 ◽  
Author(s):  
Zongjun Tian ◽  
Lida Shen ◽  
Zhidong Liu ◽  
Yinhui Huang
Keyword(s):  
High Temperature ◽  
Oxidation Resistance ◽  
Plasma Spraying ◽  
High Temperature Oxidation ◽  
Intermetallic Alloys ◽  
Laser Remelting ◽  
Temperature Oxidation ◽  
Mcraly Coatings ◽  
Tial Intermetallics ◽  
Plasma Sprayed

In order to further improve the high-temperature oxidation resistance of TiAl intermetallic alloys, MCrAlY coatings were fabricated by plasma spraying and plasma spraying-laser remelting technologies. The microstructures of the as-sprayed and laser-remelted MCrAlY coatings were studied. In addition, the oxidation behaviors at 850 °C for three samples were investigated. One sample is the matrix of TiA1 intermetallic alloys, the other one is processed by plasma-spraying MCrAlY coatings, and the third one is processed by plasma-spraying and laser-remelting MCrAlY coatings. It was revealed that the oxidation resistance of TiAl intermetallics is weak due to lack of protection of Al2O3 film formed on the surface. The plasma-sprayed MCrAlY coatings have better oxidation resistance than the TiAl intermetallics although the plasma-sprayed MCrAlY coatings have high density of porosity and a typical layered structure. It is demonstrated that most of the holes can be eliminated by laser remelting, leading to the best oxidation resistance of the third sample with the laser-remelted coatings. The high oxidation resistance of the laser-remelted coatings is mainly attributed to three aspects: firstly, an Al enriched zone on the coating surface is formed during laser remelting, which is transformed into a protective Al2O3 film during oxidation process. Secondly, laser remelting eliminates most of the defects in plasma-sprayed coatings and enhances its density, thus decreases the channel of oxidation diffusion in high temperature oxidation process. Thirdly, rapid cooling of laser remelting results in a grain refinement and a preferred oxidation of Al at the initial stage, leading to a reduction of oxidation rate.

High Temperature Oxidation and Microstructural Evolution of Modified MCrAlY Coatings

2013 ◽  
Vol 45 (3) ◽  
pp. 1401-1408 ◽  
Author(s):  
Giovanni Pulci ◽  
Jacopo Tirillò ◽  
Francesco Marra ◽  
Fabrizio Sarasini ◽  
Alessandra Bellucci ◽  
...  
Keyword(s):  
High Temperature ◽  
Microstructural Evolution ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
Mcraly Coatings

In situ Raman spectroscopy study on the effect of antioxidants on high temperature oxidation properties of TMPTO

2019 ◽  
Vol 71 (5) ◽  
pp. 706-711 ◽  
Author(s):  
Bingxue Cheng ◽  
Haitao Duan ◽  
Yongliang Jin ◽  
Lei Wei ◽  
Jia Dan ◽  
...  
Keyword(s):  
Raman Spectroscopy ◽  
High Temperature ◽  
Thermal Oxidation ◽  
High Temperature Oxidation ◽  
Isothermal Oxidation ◽  
In Situ Raman Spectroscopy ◽  
Temperature Oxidation ◽  
Content Type ◽  
Structure Changes ◽  
Oxidation Properties

Purpose This paper aims to investigate the thermal oxidation characteristics of the unsaturated bonds (C=C) of trimethylolpropane trioleate (TMPTO) and to reveal the high temperature oxidation decay mechanism of unsaturated esters and the nature of the anti-oxidation properties of the additives. Design/methodology/approach Using a DXR laser microscopic Raman spectrometer and Linkam FTIR600 temperature control platform, the isothermal oxidation experiments of TMPTO with or without 1.0 wt. % of different antioxidants were performed. Findings The results indicated that the Raman peaks of =C-H, C=C and -CH2- weaken gradually with prolonged oxidation time, and the corresponding Raman intensities drop rapidly at higher temperatures. The aromatic amine antioxidant can decrease the attenuation of peak intensity, as it significantly reduces the rate constant of C=C thermal oxidation. The hindered phenolic antioxidant has a protective effect during the early stages of oxidation (induction period), but it may accelerate the oxidation of C=C afterwards. Originality/value Research on the structure changes of synthetic esters during oxidation by Raman spectroscopy will be of great importance in promoting the use of Raman spectroscopy to analyze the oxidation of lubricants.

scholarly journals Manufacturing And High Temperature Oxidation Properties Of Electro-Sprayed Fe-24.5% Cr-5%Al Powder Porous Metal

2015 ◽  
Vol 60 (2) ◽  
pp. 1169-1173
Author(s):  
Kee-Ahn Lee ◽  
Jae-Sung Oh ◽  
Young-Min Kong ◽  
Byoung-Kee Kim
Keyword(s):  
High Temperature ◽  
High Temperature Oxidation ◽  
Porous Metal ◽  
Porous Metals ◽  
Temperature Oxidation ◽  
Spray Process ◽  
Surface Areas ◽  
Thermal Gravimetry ◽  
Oxidation Properties ◽  
Al Powder

Abstract Fe-Cr-Al based Powder porous metals were manufactured using a new electro-spray process, and the microstructures and high-temperature oxidation properties were examined. The porous materials were obtained at different sintering temperatures (1350°C, 1400°C, 1450°C, and 1500°)C and with different pore sizes (500 μm, 450 μm, and 200 μm). High-temperature oxidation experiments (TGA, Thermal Gravimetry Analysis) were conducted for 24 hours at 1000°C in a 79% N2+ 21% O2, 100 mL/min. atmosphere. The Fe-Cr-Al powder porous metals manufactured through the electro-spray process showed more-excellent oxidation resistance as sintering temperature and pore size increased. In addition, the fact that the densities and surface areas of the abovementioned powder porous metals had the largest effects on the metal’s oxidation properties could be identified.

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