Corrosion of the Materials in Sulfuric Acid

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Hong Pyo Kim ◽  
Dong-Jin Kim ◽  
Hyuk Chul Kwon ◽  
Ji Yeon Park ◽  
Yong Wan Kim
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Hydrogen Production ◽  
Cross Sectional ◽  
Corrosion Morphology ◽  
X Ray ◽  
Nuclear Heat ◽  
Corrosion Behaviors ◽  
Materials Used ◽  
Surface Morphologies

A program for a hydrogen production by using a high temperature nuclear heat has been launched in Korea since 2004. Iodine sulfur (IS) process is one of the promising processes for a hydrogen production because it does not generate carbon dioxide and a massive hydrogen production may be possible. However, the highly corrosive environment of the process is a barrier to its application in the industry. Therefore, corrosion behaviors of various materials were evaluated in sulfuric acid to select appropriate materials compatible with the IS process. The materials used in this work were Ni based alloys, Fe–Si alloys, Ta, Au, Pt, Zr, SiC, and so on. The test environments were boiling 50 wt % sulfuric acid without/with HI as an impurity and 98 wt % sulfuric acid. The surface morphologies and cross-sectional areas of the corroded materials were examined by using the scanning electron microscopy (SEM) equipped with energy dispersive X-ray spectroscopy (EDS). From the results of the weight loss and potentiodynamic experiments, it was found that a Si enriched oxide is attributable to a corrosion resistance for materials including Si in boiling 98 wt % sulfuric acid. Moreover, the passive Si enriched film thickness increased with the immersion time leading to an enhancement of the corrosion resistance. Corrosion behaviors of the material tested are discussed in terms of the chemical composition of the materials, the corrosion morphology, and the surface layer’s composition.

Corrosion of the Materials in Sulfuric Acid

2008 ◽  
Author(s):  
Hong Pyo Kim ◽  
Dong-Jin Kim ◽  
Hyuk Chul Kwon ◽  
Ji Yeon Park ◽  
Yong Wan Kim
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Hydrogen Production ◽  
Immersion Time ◽  
Cross Sectional ◽  
Corrosion Morphology ◽  
Nuclear Heat ◽  
Corrosion Behaviors ◽  
Materials Used ◽  
Surface Morphologies

The program for hydrogen production with high temperature nuclear heat has been launched in Korea since 2004. Iodine sulfur (IS) process is one of the promising processes for a hydrogen production because it does not generate a carbon dioxide and massive hydrogen production may be possible. However, the highly corrosive environment of the process is barrier to the application in the industry. Therefore, corrosion behaviors of various materials were evaluated in sulfuric acid to select appropriate materials compatible with the IS process. The materials used in this work were Ni base alloys, Fe-Si alloys, Ta, Au, Pt, Zr, SiC and so on. The test environments were boiling 50wt% sulfuric acid without/with HI as an impurity and 98wt% sulfuric acid. The surface morphologies and cross sectional areas of the corroded materials were examined by using SEM equipped with EDS. From the results of the weight loss and potentiodynamic experiments, it was found that a Si enriched oxide is attributable to a corrosion resistance for materials including Si in boiling 98wt% sulfuric acid. Moreover the passive Si enriched film thickness increased with the immersion time leading to an enhancement of the corrosion resistance. Corrosion behaviours of the material tested are discussed in terms of the chemical composition of the materials, a corrosion morphology and the surface layer’s composition.

Electropolishing of 316L Stainless Steel Using Sulfuric Acid-Free Electrolyte

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Wei Han ◽  
Fengzhou Fang
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Phosphoric Acid ◽  
Photoelectron Spectroscopy ◽  
316L Stainless Steel ◽  
Electrochemical Analysis ◽  
Limiting Current ◽  
Plateau Region ◽  
X Ray

Abstract The study is to investigate the electropolishing characteristics of 316L stainless steel in a sulfuric acid-free electrolyte of phosphoric acid and glycerol and to explore the possibility of using this eco-friendly electrolyte instead of the widely used sulfuric acid-based electrolyte. The influences of process parameters on polishing effects and the corrosion resistance of electropolished samples are investigated. The experimental results show that the electropolishing temperature and acid concentration are directly related to the mass transport mechanism in the limiting current plateau region. The grain boundaries of workpiece were electrochemically dissolved faster than the grain themselves at the beginning of the electropolishing process because they are more reactive than grains. Moreover, the conventional sulfuric—phosphoric acid electrolyte was also used to electropolish the 316L stainless steel, and the electropolished surfaces were compared with the sulfuric acid-free electrolyte proposed in this study. When the sulfuric acid-free electrolyte was used to electropolish the 316L stainless steel, the X-ray photoelectron spectroscopy (XPS) analysis shows that atomic Cr/Fe ratio of 316L stainless steel was increased from 0.802 to 1.909 after electropolishing process in the sulfuric acid-free electrolyte of phosphoric acid and glycerol. The corrosion resistance of the electropolished 316L stainless steel is studied using electrochemical analysis, and the results are verified experimentally.

The combined erosion and corrosion resistance of WC-Ni vacuum brazed coating

2017 ◽  
Vol 64 (6) ◽  
pp. 626-633 ◽  
Author(s):  
Hyung Goun Joo ◽  
Kang Yong Lee ◽  
Guo Ming Luo ◽  
Da Quan Zhang
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Coating Layer ◽  
Diffusion Coating ◽  
Test Time ◽  
Content Type ◽  
X Ray ◽  
Combined Test ◽  
Material Erosion ◽  
Corrosion Behaviors

Purpose The purpose of this paper is to investigate the combined erosion and corrosion behavior of WC-Ni vacuum brazed coating. Design/methodology/approach Al2O3 particles and 10 wt% NaCl solution are used to evaluate erosion and corrosion resistance of WC-Ni vacuum brazed coating. Combined test of erosion and corrosion is also conducted. The microstructure of each specimen is characterized by the scanning electron microscopy. The chemical composition was determined by energy-dispersive X-ray spectroscopy. Findings WC-Ni vacuum brazed coating layer is effective protective coating under combined erosion and corrosion environment. The weight loss of coating layer is more reduced as the cumulative test time. Originality/value WC-Ni vacuum brazed coatings are investigated to check characteristic of the combined erosion and corrosion environment. WC-Ni vacuum brazed coatings are kind of diffusion coating that attract attention because of the resistance of superb impact and corrosion in comparison with other coatings. Some previous researches reported the properties of vacuum brazed WC material. Erosion and corrosion behaviors of WC-Ni vacuum brazed coatings were studied in our previous research, respectively. Hence, in this research, the principal objective is to examine the combined erosion and corrosion behavior of WC-Ni vacuum brazed coating.

scholarly journals Improving Corrosion Resistance of Magnesium Alloy in Cl- Containing Simulated Concrete Pore Solution by Ultrasound-Assisted Chemical Deposition

Scanning ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Ye Wang ◽  
Guosong Wu
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloys ◽  
Pore Solution ◽  
Chemical Deposition ◽  
Deposition Process ◽  
Cross Sectional ◽  
X Ray ◽  
Electrochemical Tests ◽  
Reaction Solution ◽  
Building Engineering

Coatings are playing an important role in corrosion mitigation of magnesium alloys, and in this study, a facile and eco-friendly chemical deposition process is proposed to improve the corrosion resistance of magnesium-neodymium alloys. The mixture of 1.5 mol/L KH2PO4 solution and 1.2 mol/L CaCl2 solution is used for reaction solution, and ultrasound is introduced into the process for assisting the chemical deposition. After 40 minutes of the surface treatment, the surface and cross-sectional morphologies are observed by scanning electron microscope (SEM), which reveals that a layer of dense coating is formed on Mg alloy. Energy-dispersive X-ray spectroscopy (EDS) and X-ray Diffraction (XRD) are further combined to analyze the coating, and it is thereby confirmed that this coating mainly consists of CaHPO4·2H2O. Electrochemical tests and soaking experiments are conducted to evaluate the corrosion resistance of the treated samples in simulated concrete pore solutions. Both the untreated and treated samples have a good corrosion resistance in the Cl- free simulated concrete pore solution, but their corrosion behavior is influenced by the introduction of Cl- in this study. Fortunately, the coating can protect the substrate effectively in the Cl- containing simulated concrete pore solution. In summary, it provides a possible way for magnesium alloys to improve their corrosion resistance when they are used in building engineering.

Preparation and Salt Spray Corrosion Resistance of Ni/BN and NiCrAl/BN Coatings

2013 ◽  
Vol 537 ◽  
pp. 67-70
Author(s):  
Feng Zhang ◽  
Chuan Bing Huang ◽  
Wei Liu ◽  
Kui Zhou ◽  
Wen Ting Zhang ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Test ◽  
Open Circuit Potential ◽  
Salt Spray ◽  
Open Circuit ◽  
X Ray Diffraction ◽  
Salt Spray Corrosion ◽  
X Ray ◽  
Corrosion Behaviors ◽  
Scanning Electron

Ni/BN and NiCrAl/BN abradable sealing coatings used in turbo engines were prepared by plasma spray technology. The phases and the microstructures of the coatings were characterized with X-ray diffraction (XRD) and scanning electron microscopy (SEM). Corrosion behaviors of these coatings were investigated with open-circuit potential (OCP) and salt spray corrosion test. The results showed that the NiCrAl/BN possess better corrosion resistance as compared with Ni/BN.

Electroless Ni-P-SiO2 Composite Coatings and their Corrosion Behaviors in Simulated Furnace Flue Gas

2010 ◽  
Vol 160-162 ◽  
pp. 1464-1468
Author(s):  
Feng Hou ◽  
Hong Xu ◽  
Yu Lin Dai ◽  
Zhi Yan Yao ◽  
Cao Yan
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Carbon Steel ◽  
Flue Gas ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Electroless Nickel ◽  
Electrochemical Tests ◽  
Corrosion Behaviors ◽  
Electroless Ni

Over the last ten years, sulfuric acid dewpoint corrosion has become a more important concern in refinery furnaces since sulfur levels in fuels have increased. Electroless nickel phosphorous coating is one of the most widely used industrial coatings owing to its good corrosion resistance in many highly corrosive environments. In this work, electroless Ni-P-SiO2 composite coatings were prepared on AISI 1020 carbon steel. And the corrosion behaviors of Ni-P-SiO2, Ni-P coatings and carbon steel substrate were evaluated by immersion, electrochemical tests in 5%wt sulfuric acid solution, and dewpoint corrosion tests in simulated furnace flue gas. The experimental results indicated that corrosion resistance properties of Ni-P-SiO2 coating was best, followed by Ni-P coating and carbon steel was worst.

Microstructure and properties of pure aluminum prepared by spark plasma sintering

2019 ◽  
Vol 116 (3) ◽  
pp. 312 ◽  
Author(s):  
Wen Zeng ◽  
Weicai Qin ◽  
Cheng Gu ◽  
Hao Sun ◽  
Yilong Ma ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Spark Plasma Sintering ◽  
Sintering Temperature ◽  
Pure Aluminum ◽  
Triple Junctions ◽  
Corrosion Morphology ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Microstructure Density

Pure Aluminum (Al) powder was densified by spark plasma sintering (SPS). The effects of sintering temperature (450–600 °C) on microstructure, density, hardness and corrosion resistance of the sintered samples were investigated. The methods used in the present study were scanning electron microscopy equipped with energy dispersive X-ray spectroscopy, X-ray diffraction, electrochemical workstation and hardness measurements. The results show that the sintering temperature obviously affects the hardness, relative density, microstructures and corrosion resistance of the sintered Al samples. However, there are different trends with increasing sintering temperature. The maximum hardness (37.7 HV) was obtained at the sample sintered at 550 °C. The polarization curves and corrosion morphology analyses indicated that the sample sintered at 450 °C has the best corrosion resistance (Icorr = 0.344 µA · cm−2). Besides, it was found that the sample sintered at 600 °C was burnt and had many holes along grain boundaries and at triple junctions.

scholarly journals Effect of the Alloying Metal on the Corrosion Resistance of Pd-Rich Binary Alloys with Pt, Rh, and Ru in Sulfuric Acid

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2923
Author(s):  
Katarzyna Hubkowska ◽  
Julian Kubisztal ◽  
Małgorzata Pająk ◽  
Bożena Łosiewicz ◽  
Andrzej Czerwiński
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Room Temperature ◽  
Electrochemical Impedance ◽  
Binary Alloys ◽  
Roughness Factor ◽  
Kelvin Probe ◽  
X Ray ◽  
The Difference ◽  
Scanning Electron

The paper presents the study of the corrosion resistance of electrodeposited Pd and its binary alloys with Pt, Rh, and Ru on a polycrystalline Au substrate. The corrosion resistance was tested in 0.5 M sulfuric acid at room temperature using potentiodynamic polarization and electrochemical impedance spectroscopy techniques. The morphology/composition and work function values were determined by scanning electron microscopy/energy–dispersive X–ray spectroscopy and scanning Kelvin probe, respectively. The obtained results revealed that the Pd electrode is the most resistant to corrosion, whereas the Pd-Ru electrode is the most susceptible to dissolution. It was found that the corrosion resistance of Pd-binary alloys decrease in the following order: Pd > Pd-Pt > Pd-Rh > Pd-Ru. This effect was assigned mainly to the difference in surface roughness factor of tested electrodes.

scholarly journals Improvement of Corrosion Resistance of Stainless Steel Welded Joint Using a Nanostructured Oxide Layer

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 838
Author(s):  
Jun Heo ◽  
Sang Yoon Lee ◽  
Jaewoo Lee ◽  
Akram Alfantazi ◽  
Sung Oh Cho
Keyword(s):  
Stainless Steel ◽  
Corrosion Resistance ◽  
Oxide Layer ◽  
Electrochemical Impedance ◽  
304 Stainless Steel ◽  
Gas Tungsten Arc ◽  
Nanostructured Oxide ◽  
Corrosion Behaviors ◽  
Surface Morphologies ◽  
Type 304

In this study, we fabricated a nanoporous oxide layer by anodization to improve corrosion resistance of type 304 stainless steel (SS) gas tungsten arc weld (GTAW). Subsequent heat treatment was performed to eliminate any existing fluorine in the nanoporous oxide layer. Uniform structures and compositions were analyzed with field emission scanning electron microscope (FESEM) and X-ray diffractometer (XRD) measurements. The corrosion resistance of the treated SS was evaluated by applying a potentiodynamic polarization (PDP) technique and electrochemical impedance spectroscopy (EIS). Surface morphologies of welded SS with and without treatment were examined to compare their corrosion behaviors. All results indicate that corrosion resistance was enhanced, making the treatment process highly promising.

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