Effect of Dissolution of Oxide Film on Oxidation of Zr-1%Nb Alloy in Air and Pressurized Steam at 450 C

CORROSION ◽  
1970 ◽  
Vol 26 (4) ◽  
pp. 131-134
Author(s):  
I. A. EL-SHANSHOURY ◽  
M. E. EL-DAHSHAN
Keyword(s):  
Activation Energy ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Oxide Film ◽  
Corrosive Medium ◽  
Oxidation Rate ◽  
Treatment Process ◽  
Annealing Temperature ◽  
Vacuum Annealing ◽  
Oxygen Ion

Abstract The corrosion behavior of oxidized and vacuum annealed Zr-1%Nb alloy was investigated at 450 C (842 F) in air and pressurized steam. The corrosion resistance of partially dissolved oxide films was found to decrease with the increase in the vacuum annealing temperature up to 600 C (1112 F). A linear relationship between the logarithm of the oxidation rate and the annealing temperature was obtained from which an activation energy of 39.5 K.cal/mole was calculated. The activation energy was found to be independent of the corrosive medium. The increase in corrosion rate is explained on the fact that oxygen ion vacancy gradient increases with the increase in the annealing temperature. The decrease of the corrosion rate in steam after vacuum annealing is attributed to the release of H2 and H during the treatment process.

Effect of Annealing on the Properties of Surface Nanocrystallized CP-Ti

2011 ◽  
Vol 695 ◽  
pp. 162-165
Author(s):  
Cong Hui Zhang ◽  
Xiao Mei He ◽  
Xin Zhe Lan ◽  
Xi Cheng Zhao
Keyword(s):  
Corrosion Resistance ◽  
Polarization Curve ◽  
Annealing Temperature ◽  
Vacuum Annealing ◽  
Optical Microscope ◽  
Nanostructured Surface ◽  
Before And After ◽  
Different Temperatures ◽  
Cp Ti ◽  
Better Than

Vacuum annealing was carried out for the SMAT treated CP-Ti sample at different temperatures. The structure and the properties of the SMAT sample before and after the annealing were analyzed by means of the optical microscope, hardness and polarization curve testing. The results show that, when the annealing temperature of surface nanocrystallized CP-Ti treated CP-Ti (SMAT) was below 350°C, the microstructure and hardness of nanostructured surface was stability, and its corrosion resistance was improved compared to non-annealing one. In particular, the corrosion resistance at 150°C was better than that of the original CP-Ti.

Effect of Final Annealing Temperature on Corrosion Resistance of SZA-6 Zirconium Alloy Cladding Tubes

2019 ◽  
Vol 944 ◽  
pp. 488-498
Author(s):  
Zhong Bo Yang ◽  
Jing Jing Liao ◽  
Shao Yu Qiu ◽  
Zhu Qing Cheng ◽  
Hong Liu ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Corrosion Resistance ◽  
Weight Gain ◽  
Oxide Film ◽  
Zirconium Alloy ◽  
Annealing Temperature ◽  
Pure Water ◽  
Final Annealing ◽  
Weight Gains

The corrosion resistance of SZA-6 zirconium alloy(Zr-0.5Sn-0.5Nb-0.3Fe-0.015Si) cladding tubes finally annealed at 480°C, 510°C and 560°C were studied by static autoclave in 360°C/18.6 MPa pure water and 360°C/18.6 MPa/0.01 mol/L LiOH aqueous solution. The microstructure of the samples before and after corrosion were analyzed by EBSD, TEM and SEM. The results showed that the corrosion weight gains of the three SZA-6 alloy samples were lower than that of Zr-4 alloy after 500 days corrosion in both hydrochemical mediums. After long-term corrosion, the corrosion weight gains of SZA-6 alloy in pure water and LiOH aqueous solution increased obviously with the final annealing temperature, while the corrosion weight gain of unstressed Zr-4 alloy was higher than that of recrystallized under the same condition. With the increase of the final annealing temperature, the high-angle grain boundaries in the alloy larger than 15° became more and recrystallization degree also increased. The Second Phase Precipitates (SPPs) were fine, uniform, and dispersively distributed with an average diameter of about 120 nm. Although the size and distribution of the SPPs were similar, the Nb/Fe ratio in the SPPs increased. The long-term corrosion weight gain of zirconium alloy was related to the number of parallel cracks in the oxide film and the uneven growth degree of the oxide film on the interface of the oxide film/matrix. The corrosion resistance of the alloy in two hydrochemical mediums was related to the degree of recrystallization and the content of Nb in the SPPs. Increasing the final annealing temperature would promote the formation of fine and uniform recrystallized grains, which was benefit to the corrosion resistance, but at the same time it would reduce the content of solid solution Nb in the αZr matrix, which in turn would be detrimental to the corrosion resistance.

Corrosion Inhibition of a Gas Sparged Copper Cylinder in a Solution of NaCl and Na2S by Using 4-Amino-4H-1,2,4-triazole as Corrosion Inhibitor

2016 ◽  
Vol 19 (3) ◽  
pp. 163-167
Author(s):  
Saad Said Al-Shahrani
Keyword(s):  
Activation Energy ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Corrosion Inhibition ◽  
Gas Flow ◽  
Inhibitor Concentration ◽  
Gas Velocity ◽  
Gas Flow Rate ◽  
Triazole Derivatives ◽  
Copper Cylinder

Most of previous investigations for corrosion inhibition of copper using triazole derivatives were carried out in stagnant conditions and mainly in presence either NaCl or Na2S. The main aim of this work is to investigate the performance of one of triazole derivatives namely, 4-Amino-4H-1,2,4-triazole (AHT) on improving the corrosion resistance of gas sparged copper parts in a solution comprised of NaCl and Na2S with different propotions. The potentiodynamic technique was used for investigating the effect of different variables on the corrosion rate of gas sparged copper such as gas velocity, initial S-2 concentration, gas sparged copper cylinder diameter, and initial AHT inhibitor concentration. The results show that the %improvement in corrosion resistance depends mainly on two main parameters, gas flow rate and amount of AHT inhibitor added. For lower gas velocities 0.07 cm/s the %improvement ranges from 6 to 22%, while for higher gas rate 0.35 cm/s it ranges from 2 to 7% depending on the amount of inhibitor added. The activation energy of the reaction was found to increase by approximately 20% by addition of the inhibitor up to 10ppm.

COOPER ALLOY 22W

Alloy Digest ◽  
1963 ◽  
Vol 12 (8) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Creep Rate ◽  
Corrosion Rate ◽  
Physical Properties ◽  
High Strength ◽  
Heat Treating ◽  
Casting Alloy ◽  
Hot Gas ◽  
Gas Corrosion ◽  
Very High

Abstract Cooper Alloy 22W is a high strength, heat resistant casting alloy with a low creep rate. It is recommended for heat applications where stress and hot gas corrosion rate are very high. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on corrosion resistance as well as casting, heat treating, machining, joining, and surface treatment. Filing Code: SS-146. Producer or source: Cooper Alloy Corporation.

scholarly journals The Hybrid Process of Low-Pressure Carburizing and Metallization (Cr + LPC, Al + LPC) of 17CrNiMo7-6 and 10NiCrMo13-5 Steels

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 567
Author(s):  
Paulina Kowalczyk ◽  
Konrad Dybowski ◽  
Bartłomiej Januszewicz ◽  
Radomir Atraszkiewicz ◽  
Marcin Makówka
Keyword(s):  
Corrosion Resistance ◽  
Surface Layer ◽  
Physicochemical Properties ◽  
Surface Treatment ◽  
Retained Austenite ◽  
Treatment Process ◽  
Active Surface ◽  
Low Pressure ◽  
Low Alloy Steel ◽  
Chromium Plating

This paper presents the concept of modification of physicochemical properties of steels by simultaneous diffusion saturation with carbon and chromium or aluminum. The application of a hybrid surface treatment process consisting of a combination of aluminizing and low-pressure carburizing (Al + LPC) resulted in a reduction in the amount of retained austenite in the surface layer of the steel. While the use of chromium plating and low-pressure carburizing (Cr + LPC) induced an improvement in the corrosion resistance of the carburized steels. It is of particular importance in case of vacuum processes after the application of which the active surface corrodes easily, as well as in case of carburizing of low-alloy steel with nickel, where an increased content of retained austenite in the surface layer is found after carburizing.

Doping Effect in Nickel Oxide

2009 ◽  
Vol 289-292 ◽  
pp. 775-782 ◽  
Author(s):  
Zbigniew Jurasz ◽  
Krzysztof Adamaszek ◽  
Romuald Janik ◽  
Zbigniew Grzesik ◽  
Stanisław Mrowec
Keyword(s):  
Activation Energy ◽  
Nickel Oxide ◽  
High Temperatures ◽  
Oxygen Pressure ◽  
Pressure Dependence ◽  
Oxidation Rate ◽  
Doping Effect ◽  
Self Diffusion ◽  
Electron Holes ◽  
Influence Of Impurities

Detailed investigations of nonstoichiometry as well as chemical and self-diffusion in nickel oxide have shown that doubly ionised cation vacancies and electron holes are the predominant defects in this material. The present work is an attempt to demonstrate that aliovalent impurities (Cr, Al, Na and Li) may considerably influence the concentration of these defects and, consequently, the oxidation rate of nickel at high temperatures. It has been shown that small amounts of tri-valent impurities (Cr, Al) bring about an increase of the oxidation rate, while mono-valent ones (Li, Na) decrease the rate of oxidation. These phenomena may satisfactorily be explained in terms of a doping effect. All experiments have been carried out as a function of temperature (1373-1673 K) and oxygen pressure (1-105 Pa) and consequently, it was possible to determine the influence of impurities not only on the oxidation rate but also on the activation energy of reaction and its pressure dependence. The results of these investigations could again be elucidated in terms of doping effect.

Effect of Electrolyte Composition on Corrosion Resistance in Nickel Plating Process for Coating Bonded Magnet PrFeB

2014 ◽  
Vol 896 ◽  
pp. 245-248 ◽  
Author(s):  
Candra Kurniawan ◽  
Hayati M.A. Sholihat ◽  
Kemas Ahmad Zaini Thosin ◽  
Muljadi ◽  
Prijo Sardjono
Keyword(s):  
Magnetic Properties ◽  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Nickel Coating ◽  
Electrolyte Composition ◽  
Nickel Metal ◽  
Sem Images ◽  
Average Value ◽  
Immersion Corrosion ◽  
Bonded Magnet

Despite of its excellence magnetic quality, one of the critical properties of PrFeB based permanent magnet is a low corrosion resistance so it can be oxidized easily which can reduce its magnetic properties. In this study, Nickel coating has been performed for bonded PrFeB magnet by the electroplating method using Nickel-Watts bath-type as the electrolyte to improve the corrosion resistance. The varying amount of the electrolyte compounds used to have the optimized composition indicated by the corrosion resistance measurement. The solution composition used was NiSO4 (230-380 g/L), NiCl2 (30-60 g/L), and H3BO3 (30 and 45 g/L) with a fixed value of other parameters. Characterization used including the immersion corrosion test, microstructure analysis, and magnetic properties. Based on the corrosion rate measurement, the highest corrosion resistant of Nickel coated PrFeB magnet achieved from the electrolyte composition of NiSO4: NiCl2: H3BO3 = 380: 60: 30 g/L with a plating time and current density (J) of 60 minutes and 40 mA/cm2 respectively. The corrosion rate data showed that the Nickel metal coating can improve the corrosion resistance of bonded PrFeB magnet up to 29 times than of the substrate. The SEM images showed that the thickness of the Nickel coating on the optimum electrolyte composition was in average value of 35.1 µm. The overall samples has a magnetic remanence value (Br) reached ≥ 6 kG, so it has enough properties to be applied in devices such as generators and electric motors.

About the Electrical Activation of 1×1020 cm-3 Ion Implanted Al in 4H-SiC at Annealing Temperatures in the Range 1500 - 1950°C

2018 ◽  
Vol 924 ◽  
pp. 333-338 ◽  
Author(s):  
Roberta Nipoti ◽  
Alberto Carnera ◽  
Giovanni Alfieri ◽  
Lukas Kranz
Keyword(s):  
Activation Energy ◽  
Sheet Resistance ◽  
Annealing Time ◽  
Thermal Activation ◽  
Room Temperature ◽  
Annealing Temperature ◽  
Thermal Activation Energy ◽  
Electrical Activation ◽  
Temperature Range ◽  
Annealing Temperatures

The electrical activation of 1×1020cm-3implanted Al in 4H-SiC has been studied in the temperature range 1500 - 1950 °C by the analysis of the sheet resistance of the Al implanted layers, as measured at room temperature. The minimum annealing time for reaching stationary electrical at fixed annealing temperature has been found. The samples with stationary electrical activation have been used to estimate the thermal activation energy for the electrical activation of the implanted Al.

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