Cyclic Oxidation Resistance of Hot-Dipping Aluminized Steel

2016 ◽  
Vol 852 ◽  
pp. 9-13 ◽  
Author(s):  
Jin Lou ◽  
Cheng Xiang Ruan

0Cr18Ni10Ti stainless steel was coated by hot-dipping in a molten aluminum bath, and then diffusing annealing at 950 °C for 2h. Aluminized steel was composed of three layers: outer layer FeAl2 phase and FeAl phase, intermediate layer FeAl phase, and inner solid solution with Al. The cyclic oxidation resistance of aluminized steel with outer layer and aluminized steel without outer layer were tested at 900 °C for 24 cycles using resistance furnace. Morphology, and phase composition, element distribution of the oxide scale were characterized by XRD, SEM and EDS. The oxidation result showed that weight loss on aluminized steel with outer layer was observed at early stage, weigh gain was obtained slowly at later stage, while the weight gain was observed on aluminized steel without outer layer during 24 cycles. The weigh gain of both samples was about 0.7mg/cm2 after 24 cycles. It was found that cracks on aluminized steel with outer layer were more than aluminized steel without outer layer due to thicker FeAl layer on aluminized steel with outer layer. A thin NiAl phase layer was found between FeAl layer and inner solid solution layer on both samples decrease the depletion rate of aluminum.

2006 ◽  
Vol 522-523 ◽  
pp. 377-384 ◽  
Author(s):  
Michihisa Fukumoto ◽  
Motoi Hara ◽  
Toshio Narita

In order to improve the cyclic-oxidation resistance of Ni and SUS304 steel, the coating of a Ni aluminide containing La on both samples were carried out by the electrodeposition of Al and La in a molten salt. The electrodepositions of Al and La were conducted using a potentiostatic polarization method at 1023 K in an equimolar NaCl-KCl melt containing 3.5 mol%AlF3, and that containing 4 mol%La2O3-24 mol%NH4Cl, or 3.5 mol%LaF3. Observation and analysis of the cross-section of the specimen after polarization showed that a deposited layer consisting of a thick inner Ni aluminide layer and a thin outer layer containing a large amount of La was formed on both samples. The cyclic-oxidation resistance of the Ni specimen covered with the deposit layer having the La layer as the outer layer was higher than those of the untreated Ni specimen and the Ni specimen coated with the deposit layer without La. The stainless steel covered with the Ni aluminide showed a high cyclic-oxidation resistance in the atmosphere containing water vapor at 1273 K in comparison with untreated stainless steel, without depending on the existence of La in the deposited layer.


2013 ◽  
Vol 747-748 ◽  
pp. 575-581 ◽  
Author(s):  
Yu Zhuo Liu ◽  
Qiong Wu ◽  
Shu Suo Li ◽  
Yue Ma ◽  
Sheng Kai Gong

An Al-Si coating was prepared on IC21 alloy by powder pack cementation. The cyclic oxidation tests were carried out at 1150 in air for up to 100 h. The results indicate that the oxidation resistance of IC21 alloy is significantly improved by the Al-Si coating due to the presence of Ni2Al3and β-NiAl enriched outer layer, and Si can effectively supress the outward diffusion of Mo. The oxide scales mainly consist of α-Al2O3, which is the favorite to the oxidation resistance. Phase transformation occurred from β-NiAl to γ-Ni3Al and γ-Ni in the coating during oxidation. The coating still remained a certain amount of β phase after oxidation for 100h, which indicate a good protection. The microstructure change evolution was characterized, and the oxidation behavior of the coating was discussed.


2004 ◽  
Vol 11 (03) ◽  
pp. 337-340 ◽  
Author(s):  
E. B. HANNECH ◽  
N. LAMOUDI ◽  
A. GASMI

The growth kinetics of the solid solution phase of aluminum in copper in diffusion couples of pure aluminum and copper has been investigated at 425°C using a scanning electron microscope. In the initial stage, the phase layer growth was found to obey the parabolic law, indicating that the rate-controlling process is diffusion. At longer times, the growth rate deviates from the kt-1/2 behavior of the early stage.


2014 ◽  
Vol 1061-1062 ◽  
pp. 436-440
Author(s):  
Jin Lou ◽  
Cheng Xiang Ruan

GH169 superalloy steel was coated by hot-dipping in a molten aluminum bath, and then diffusing annealing at 950 °C for 2h. The cyclic oxidation behaviors of the hot-dipped aluminized steel and GH169 were tested at 900 °C for 24 cycles using resistance furnace. Morphology of surface and cross-section, element distribution of the oxide scale were characterized by SEM and EDS. The results showed that protective Cr2O3 and Al2O3 oxide scales were formed on GH169 and aluminized steel after 24 cycles, respectively. The inner oxidation was found on GH169 after 24 cycles. It was composed of surface Al2O3 oxide film, outer Al-rich layer scattered with NiAl phase, and inner NiAl layer on aluminized steel after 24 cycles at 900°C.


Alloy Digest ◽  
1970 ◽  
Vol 19 (12) ◽  

Abstract PYROMET 538 is a solid-solution strengthened, austenitic alloy with a desirable combination of strength, corrosion resistance, oxidation resistance, and economy. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-247. Producer or source: Carpenter Technology Corporation.


2013 ◽  
Vol 49 (11) ◽  
pp. 1369 ◽  
Author(s):  
Ziqi GONG ◽  
Ziyong CHEN ◽  
Lihua CHAI ◽  
Zhilei XIANG ◽  
Zuoren NIE

Author(s):  
Huilin Lun ◽  
Yi Zeng ◽  
Xiang Xiong ◽  
Ziming Ye ◽  
Zhongwei Zhang ◽  
...  

AbstractMulti-component solid solutions with non-stoichiometric compositions are characteristics of ultra-high temperature carbides as promising materials for hypersonic vehicles. However, for group IV transition-metal carbides, the oxidation behavior of multi-component non-stoichiometric (Zr,Hf,Ti)Cx carbide solid solution has not been clarified yet. The present work fabricated four kinds of (Zr,Hf,Ti)Cx carbide solid solution powders by free-pressureless spark plasma sintering to investigate the oxidation behavior of (Zr,Hf,Ti)Cx in air. The effects of metallic atom composition on oxidation resistance were examined. The results indicate that the oxidation kinetics of (Zr,Hf,Ti)Cx are composition dependent. A high Hf content in (Zr,Hf,Ti)Cx was beneficial to form an amorphous Zr-Hf-Ti-C-O oxycarbide layer as an oxygen barrier to enhance the initial oxidation resistance. Meanwhile, an equiatomic ratio of metallic atoms reduced the growth rate of (Zr,Hf,Ti)O2 oxide, increasing its phase stability at high temperatures, which improved the oxidation activation energy of (Zr, Hf, Ti)Cx.


2014 ◽  
Vol 528 ◽  
pp. 25-29
Author(s):  
Ling Yun Bai ◽  
Xian Chao Xu ◽  
Jun Huai Xiang ◽  
Yun Xiang Zheng ◽  
Jun Wang

The cyclic oxidation behavior of Co-10Cr-5Al alloys in atmosphere at 700 °C was investigated. The addition of 0.3 at.% Y changed the oxidation behavior from the approximate parabolic rate law to complex mode. The scale grown on the surface of Co-10Cr-5Al cracked seriously, while the oxide scale the Y doped alloy had better adhesive property. Yttrium doped in the sample promoted the forming of continuous Al2O3layer and decreased the oxidation rate of Co-10Cr-5Al alloys.


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