Microstructure and corrosion behavior of micro-arc oxidation coating on 6061 aluminum alloy pre-treated by high-temperature oxidation

2013 ◽  
Vol 287 ◽  
pp. 451-456 ◽  
Author(s):  
Dejiu Shen ◽  
Guolong Li ◽  
Changhong Guo ◽  
Jie Zou ◽  
Jingrui Cai ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Corrosion Behavior ◽  
High Temperature Oxidation ◽  
Temperature Oxidation ◽  
6061 Aluminum Alloy ◽  
Micro Arc Oxidation

Carbide Fragmentation and Dissolution in a High-Carbon High-Chromium Steel Using Hot Rolling Process: Microstructure Evolution, Wear, High-Temperature Oxidation, and Chloride-Induced Corrosion Properties

CORROSION ◽  
10.5006/2749 ◽  
2018 ◽  
Vol 74 (9) ◽  
pp. 958-970 ◽  
Author(s):  
Majid Shahsanaei ◽  
Sadegh Pour-Ali ◽  
Ali-Reza Kiani-Rashid ◽  
Sannakaisa Virtanen
Keyword(s):  
High Temperature ◽  
Corrosion Behavior ◽  
Hot Rolling ◽  
High Temperature Oxidation ◽  
Rolling Process ◽  
High Carbon ◽  
Corrosion Properties ◽  
Temperature Oxidation ◽  
High Chromium ◽  
Hot Rolling Process

A series of hot rolling processes with different reduction percentages (10%, 30%, and 50%) were applied to a high-carbon high-chromium tool steel (2HCTS). Microstructural evolutions, wear behavior, high-temperature oxidation, and aqueous corrosion properties were investigated. The results revealed the breakage and dissolution of primary carbides and a uniform carbide distribution after the hot rolling process. It was proposed that the presence of higher amounts of dissolved chromium in the hot rolled samples leads to the formation of Cr-rich oxides with more protection and less porosity at high temperatures, as well as an improved corrosion behavior in 3.5 wt% NaCl solution. This improvement in the corrosion behavior is not at the expense of the degradation of wear resistance. Probable mechanisms for carbides dissolution are also discussed.

Microstructure and High-Temperature Oxidation of Ni-Si3N4 Composite Coatings by Pulse Electrodeposition

2015 ◽  
Vol 817 ◽  
pp. 421-425
Author(s):  
Kun Zhao ◽  
Wan Chang Sun ◽  
Chun Yu Miao ◽  
Hui Cai ◽  
Ju Mei Zhang ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Composite Coatings ◽  
X Ray Diffraction ◽  
Temperature Oxidation ◽  
Electro Deposition ◽  
X Ray ◽  
Crystallite Structure

Nickel matrix and Si3N4 micron particles were co-deposited on the aluminum alloy by pulse electro-deposition for high temperature performance. Meanwhile, the oxidation resistance was evaluated through the high temperature oxidation test. The phase structure, micrographs and components of the composite coatings were investigated by means of X-ray diffraction (XRD), scanning electron microscopy (SEM) together with energy dispersive spectroscopy (EDS) respectively. The results indicated that Si3N4 particles were uniformly distributed across the coating and there were no pores and cracks or other defects at the coating/substrate interface. Ni-Si3N4 composite coatings are characterized by pyramidal micro-crystallite structure. The thickness of Ni-Si3N4 composite coatings were up to 80 μm for 2h. The results also revealed that the Ni-Si3N4 composite coatings presented better oxidation resistance than the pure Ni coating and aluminum alloy at high temperature. After oxidation at 673 K for 8h, the oxidation resistance of Ni-Si3N4 composite coatings presented the improved oxidation resistance behavior compared to pure Ni and the aluminum alloy, respectively.

scholarly journals New Formation Mechanisms of Pores and Cracks in Micro-arc Oxidation Coatings on 6061 Aluminum Alloy with High Temperature Oxide Prefab Film

2021 ◽  
Vol 27 (1) ◽  
pp. 37-41
Author(s):  
Guo-rui WU ◽  
Dong-dong WANG ◽  
Xin-tong LIU ◽  
Mingjia WANG ◽  
Dong CHEN ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
High Temperature ◽  
Phase Interface ◽  
Oxide Phase ◽  
Formation Mechanisms ◽  
Coating Materials ◽  
6061 Aluminum Alloy ◽  
High Temperature Oxide ◽  
Micro Arc Oxidation ◽  
Temperature Oxide

Prior to micro-arc oxidation (MAO) treatment, a layer of high temperature oxide (HTO) prefab film was fabricated on the surface of 6061 aluminum alloy specimens. The formation mechanisms of the cracks and pores in the MAO coatings were investigated by means of Mg element as the tracer. The results showed that there were several different formation mechanisms for the pores and cracks formed in the MAO coatings as follows. Some of pores were attributed to the residual micro-discharge channels, and the others were attributed to the residual uncovered concave regions locating among the surrounding convex regions. The difference in oxide phase composition caused by the compositional fluctuations in the coating weakened the bond strength at the phase interface and resulted in forming cracks between every two convex regions. Some of cracks were resulted from the solidification and shrinkage of molten coating materials, and the others were resulted from the poor connection between every two convex regions. The surface morphology and the content of each element of the MAO coating were determined using scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS).

Study on Properties of Al2TiO5 Coating on Ti-6Al-4V Titanium Alloy

2013 ◽  
Vol 575-576 ◽  
pp. 348-351
Author(s):  
Nian Suo Xie ◽  
Jin Wang
Keyword(s):  
Corrosion Resistance ◽  
Titanium Alloy ◽  
Sulfuric Acid ◽  
High Temperature ◽  
Oxidation Resistance ◽  
High Temperature Oxidation ◽  
Acid Corrosion ◽  
Temperature Oxidation ◽  
Micro Arc Oxidation ◽  
Sulfuric Acid Corrosion

The Al2TiO5Coating was deposited on Ti-6Al-4V alloy substrate by homemade micro-arc oxidation system. The microstructure of Ti-6Al-4V titanium alloy, the phase of coating, the bonding force of the coating and matrix, sulfuric acid corrosion resistance and high-temperature oxidation resistance were study by inverted microscope model, Xray diffract meter, scanning electron microscopy, the coating adhesion automatic scratch tester, box-type furnace. The results show that the phase of coating is composed of Al2TiO5and Al2SiO5, and Al2TiO5.is the main component, the coating surface consists of discharging pit and flange which are unequal in size, rough and overlap and micro-arc oxidation pit diameter increases with the voltage. When micro-arc oxidation voltage is constant, the longer micro-arc oxidation time, the greater the Ti-6Al-4V alloy coating and the substrate binding force. The corrosion resistance of Ti-6Al-4V alloy was improved in sulfuric acid due to micro-arc oxidation; the sulfuric acid corrosion resistance of the coated samples was improved 11 times when the micro-arc oxidation time increased from 5min to 60min. the high-temperature oxidation resistance of Ti-6Al-4V alloy with micro-arc oxidation coatings is higher than Ti-6Al-4V alloy without micro-arc oxidation coating.

Comparison of High-Temperature Oxidation Onset Behavior of Sanicro 28 Steel with KCl, NaCl and K2CO3

2015 ◽  
Vol 227 ◽  
pp. 393-396
Author(s):  
Jing Xin Sui ◽  
Juho Lehmusto ◽  
Mikael Bergelin ◽  
Mikko Hupa
Keyword(s):  
Stainless Steel ◽  
High Temperature ◽  
Corrosion Behavior ◽  
High Temperature Oxidation ◽  
High Temperature Corrosion ◽  
High Alloy ◽  
Temperature Oxidation ◽  
Sanicro 28 ◽  
Alkali Salts ◽  
Reaction Initiation

This paper presents results from a study regarding the influence of three alkali salts (KCl, NaCl, and K2CO3) on the initial high temperature corrosion behavior of high alloy stainless steel Sanicro 28 (Fe31Cr27Ni) at 535°C. It was found that all three salts were corrosive, however, with clear differences in terms of reaction initiation.

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