Cyclic Oxidation and Hot Corrosion Behavior of Y/Cr-Modified Aluminide Coatings Prepared by a Hybrid Slurry/Pack Cementation Process

Reactive reactive element oxide RexOy (Re=Ce, Y)-modified aluminide coatings were developed by aluminizing the as-codeposited Ni-RexOy composite film using pack cementation method at 1100°C for 4 h. By comparison, aluminizing was also performed with the same condition on an as-deposited Ni film without RexOy particles. SEM/EDAX and TEM results indicated that the co-deposited CeO2 or Y2O3 particls were homogeneously dispersed in the finer-grain nanocrystalline Ni grains. The cyclic oxidation in air at 900°C indicated that the RexOy -modified aluminide coatings were profoundly spallation resistance as compared to the RexOy -free coatings due to the formation of a continuous adherent α-Al2O3 scale.

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Effect of Hf Addition on High Temperature Properties of Ir-Containing Alloy Coatings

Materials Science Forum ◽

10.4028/www.scientific.net/msf.546-549.1689 ◽

2007 ◽

Vol 546-549 ◽

pp. 1689-1694 ◽

Cited By ~ 2

Author(s):

Hideyuki Murakami ◽

K. Kamiya ◽

Akihiro Yamaguchi ◽

Ying Na Wu ◽

Seiji Kuroda

Keyword(s):

High Temperature ◽

Cyclic Oxidation ◽

Flat Surface ◽

Small Difference ◽

Aluminide Coating ◽

High Temperature Properties ◽

Aluminide Coatings ◽

Cyclic Oxidation Test ◽

Hf Addition ◽

Pack Cementation Process

In the present study, high temperature properties of Ir-modified and Ir-Hf-modified aluminide coatings on Ni-based single crystal superalloy TMS-82+ were discussed. They were prepared by depositing pure Ir and Ir-Hf alloys on TMS-82+ using magnetron sputtering and EB-PVD, followed by a conventional Al-pack cementation process. The effects of Hf addition on the oxidation resistance and top-coat spallation resistance were investigated. Cyclic oxidation test at 1423K for 1h as one heating cycle revealed that while there is a small difference in oxidation kinetics and spallation lives between Ir and Ir-Hf coatings, drastic difference in surface morphology was observed. After 50 oxidation cycles the Ir-modified aluminide coating showed surface rumpling whereas the Ir-Hf modified aluminide coatings kept the flat surface. It was also revealed that excessive addition of Hf promoted the internal oxidation, resulting in the deterioration of substrates. These results agree with the conventional Pt-modified aluminide coatings and Ni-Al-Hf alloys.

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A Comparative Study of Cyclic Oxidation and Sulfates-Induced Hot Corrosion Behavior of Arc-Sprayed Ni-Cr-Ti Coatings at Moderate Temperatures

Journal of Thermal Spray Technology ◽

10.1007/s11666-015-0222-6 ◽

2015 ◽

Vol 24 (5) ◽

pp. 789-797 ◽

Cited By ~ 7

Author(s):

Wenmin Guo ◽

Yuping Wu ◽

Jianfeng Zhang ◽

Sheng Hong ◽

Liyan Chen ◽

...

Keyword(s):

Comparative Study ◽

Corrosion Behavior ◽

Hot Corrosion ◽

Cyclic Oxidation

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High Temperature Oxidation Behavior of Co-Cr-Y2O3 Modified Aluminide Coatings on Ni-based Superalloy by Pack Cementation Process

Rare Metal Materials and Engineering ◽

10.1016/s1875-5372(19)30007-4 ◽

2018 ◽

Vol 47 (12) ◽

pp. 3616-3623

Author(s):

Cao Jiangdong ◽

Gong Shaojun ◽

Zhong Chonggui ◽

Yao Yanbin

Keyword(s):

High Temperature ◽

High Temperature Oxidation ◽

Oxidation Behavior ◽

Pack Cementation ◽

Temperature Oxidation ◽

Aluminide Coatings ◽

High Temperature Oxidation Behavior ◽

Pack Cementation Process

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Hot Corrosion of Aluminide Coated Ti-Al-Cr-Nb-Zr-Y Intermetallic Alloys

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1112.363 ◽

2015 ◽

Vol 1112 ◽

pp. 363-366 ◽

Cited By ~ 2

Author(s):

Eddy Basuki ◽

Fadhli Mohammad ◽

Ahmad Fauzi ◽

Djoko Prajitno

Keyword(s):

Corrosion Rate ◽

High Activity ◽

High Temperatures ◽

Corrosion Behavior ◽

Hot Corrosion ◽

Intermetallic Alloy ◽

Experimental Results ◽

Intermetallic Alloys ◽

Two Phase ◽

Aluminide Coatings

Pack aluminide coatings were performed on a Ti-Al-Cr-Nb alloy doped with zirconium and yttrium having two phase of a2-Ti3Al and g-TiAl microstructure. The high activity TiAl3-based coating was developed from aluminizing process carried out at 850°C for 25 hours in a pack containing 20%-wt Al, 2%wt NH4Cl, and 78%wt Al2O3. During applications at high temperatures, the coating can degrade due to the interaction between the coated system and the environment exhibit high corrosion potentials. This study investigates the hot corrosion behavior of high-activity aluminide coated Zr-Y doped a2-Ti3Al/g-TiAlCrNb intermetallic alloy at 700°C, 800°C, and 900°C in a mixture of 90% Na2SO4 and 10% NaCl. The experimental results showed that the addition of Zr and Y in the alloy reduces significantly the hot corrosion rate of the coating as resulted from the interdiffusion of these elements from the alloy to the coatings and influence the behavior of the TiAl3-based coatings.

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