Influence of second phase particles on corrosion resistance of N36 alloy in superheated steam

2016 ◽  
Vol 93 ◽  
pp. 84-88
Author(s):  
Liang Chen ◽  
Xiaoming Song ◽  
Hua Pang ◽  
Lili Liu
Keyword(s):  
Corrosion Resistance ◽  
Superheated Steam ◽  
Second Phase ◽  
Second Phase Particles

Effect of Bi Addition on the Corrosion Behavior of Zirconium Alloys

2013 ◽  
Author(s):  
M. Y. Yao ◽  
B. X. Zhou ◽  
Q. Li ◽  
W. P. Zhang ◽  
L. Zhu ◽  
...  
Keyword(s):  
Solid Solution ◽  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Mass Fraction ◽  
Zirconium Alloys ◽  
Deionized Water ◽  
Second Phase ◽  
Micro Structure ◽  
Second Phase Particles ◽  
Structure Observation

In order to investigate systematically the effect of Bi addition on the corrosion resistance of zirconium alloys, different zirconium-based alloys, including Zr-4 (Zr-1.5Sn-0.2Fe-0.1Cr), S5 (Zr-0.8Sn-0.35Nb-0.4Fe-0.1Cr), T5 (Zr-0.7Sn-1.0Nb-0.3Fe-0.1Cr) and Zr-1Nb, were adopted to prepare the zirconium alloys containing Bi of 0∼0.5% in mass fraction. These alloys were denoted as Zr-4+xBi, S5+xBi, T5+xBi and Zr-1Nb+xBi, respectively. The corrosion behavior of these specimens was investigated by autoclave testing in lithiated water with 0.01 M LiOH or deionized water at 360°C/18.6 MPa and in superheated steam at 400 °C/10.3 MPa. The micro structure of the alloys was examined by TEM and the second phase particles (SPPs) were analyzed by EDS. Micro structure observation shows that the addition of Bi promotes the precipitation of Sn as second phase particles (SPPs) because Sn is in solid solution in α-Zr matrix in Zr-4, S5 and T5 alloys. The concentration of Bi dissolved in α-Zr matrix increase with the increase of Nb in the alloys, and the excess Bi precipitates as Bi-containing SPPs. The corrosion results show that the effect of Bi addition on the corrosion behavior of different zirconium-based alloys is very complicated, depending on their compositions and corrosion conditions. In the case of higher Bi concentration in α-Zr, the zirconium alloys exhibit better corrosion resistance. However, in the case of precipitation of Bi-containing SPPs, the corrosion resistance gets worse. This indicates that the solid solution of Bi in α-Zr matrix can improve the corrosion resistance, while the precipitation of the Bi-containing SPPs is harmful to the corrosion resistance.

Effects of Heat Treatment on Corrosion of Zr-1.0Nb-1.0Sn-0.1Fe

2005 ◽  
Vol 475-479 ◽  
pp. 1401-1404
Author(s):  
J.H. Baek ◽  
Yong Hwan Jeong
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Annealing Time ◽  
Tetragonal Phase ◽  
Second Phase ◽  
Tetragonal Zro2 ◽  
Monotectoid Reaction ◽  
Second Phase Particles ◽  
Mean Size ◽  
The Mean

The effects of annealing at 570oC and 640oC on the microstructural and corrosion characteristics for Zr-1.0Nb-1.0Sn-0.1Fe alloy were elucidated. After annealing at 570oC below the temperature of a monotectoid reaction in the Zr-Nb system, both orthorhombic Zr3Fe and the bcc b-Nb particles were uniformly found and the mean size of the second phase particles was increased with an increasing of the annealing time. In the case of an annealing at 640oC for 2 h above the monotectoid reaction temperature, the Zr3Fe was observed intermittently and after a longer annealing of 1000 h the b-Zr particles were well developed. The corrosion resistance after the 570oC anneal was improved as the annealing time increased, while that after the 640oC anneal decreased as the annealing time increased. The fraction of the tetragonal phase within the ZrO2 oxide increased as the corrosion resistance was improved. It was concluded that the equilibrium Nb concentration and the formation of the tetragonal ZrO2 due to the b-Nb phase would lead to improving the corrosion resistance of the alloy.

Corrosion Product Films Formed on Aluminum In High Temperature Wester

CORROSION ◽  
1961 ◽  
Vol 17 (4) ◽  
pp. 181t-184t ◽  
Author(s):  
D. F. MacLENNAN
Keyword(s):  
Electron Microscopy ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Aluminum Alloys ◽  
Corrosion Product ◽  
High Purity ◽  
Second Phase ◽  
Corrosion Product Film ◽  
Second Phase Particles ◽  
Product Film

Abstract A study was made of the behavior of aluminum alloys exposed to 300 G high purity water for short periods of time. The corrosion products formed were examined by means of optical and electron microscopy. Results show that corrosion resistance is associated with the distribution of second phase particles in the alloys. The alloy, which had the best corrosion resistance, contained the most uniform distribution of cathodic second phase particles; the corrosion product film of this alloy contained a corresponding distribution of irregularities. It is suggested that the second phase particles modify the film in such a way as to increase its protective qualities. 6.4.2, 4.6.5, 3.2.3

scholarly journals Influence of heat treatment on corrosion resistance of Mg-Al-Zn alloy processed by severe plastic deformation

2018 ◽  
Vol 8 (1) ◽  
pp. 391-394 ◽  
Author(s):  
Mária Zemková ◽  
Róbert Král ◽  
Jakub Čížek ◽  
Jana Šmilauerová ◽  
Peter Minárik
Keyword(s):  
Corrosion Resistance ◽  
Dislocation Density ◽  
Electrochemical Properties ◽  
Polarization Resistance ◽  
Electron Backscatter Diffraction ◽  
Positron Annihilation Spectroscopy ◽  
Second Phase ◽  
Angular Pressing ◽  
Second Phase Particles ◽  
Backscatter Diffraction

Abstract The effect of subsequent annealing on the electrochemical properties of an AZ31 magnesium alloy processed by extrusion and equal channel angular pressing (ECAP) was investigated. The electrochemical properties were evaluated using potentiodynamic tests in corrosion solution of 0.1 M sodium chloride. The electrochemical changes after annealing were correlated with microstructure evolution. The microstructure was analyzed by scanning electron microscope (SEM) and electron backscatter diffraction (EBSD). The evolution of dislocation density was determined by positron annihilation spectroscopy (PAS). The annealing for 1h at temperatures ranging from 150∘C to 250∘C resulted in higher polarization resistance in all cases. The polarization resistance of sample annealed at 250∘C was ~17% higher compared to just ECAPed material. Combination of gradual decrease of dislocation density, grain growth and second phase particles dissolution played the crucial role in the corrosion resistance improvement.

Effects of Annealing on the Corrosion Property of CZ1 Alloy

2017 ◽  
Author(s):  
Liutao Chen ◽  
Jun Tan ◽  
Changyuan Gao ◽  
Dungu Wen ◽  
Hong Zou ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Nuclear Power ◽  
Underlying Mechanism ◽  
Corrosion Property ◽  
Second Phase ◽  
Pressurized Water Reactor ◽  
Corrosion Properties ◽  
Pressurized Water ◽  
Second Phase Particles ◽  
The Matrix

CZ alloys were developed by China General Nuclear Power Group (CGN) for pressurized water reactor. To improve the corrosion resistance, the impacts of annealing on corrosion of CZ1 alloy were studied. The fuel cladding tubes of CZ1 alloy was fabricated by different annealing processes, with intermediate annealing in the range of 560 °C to 700 °C. Then the corrosion properties of CZ1 alloy and low Tin Zr-4 specimens were investigated by autoclave tests. The matrix and second phase particles along with the oxide characteristics were analyzed. The experimental results showed that the corrosion resistance of CZ1 alloy is superior to that of low Tin Zr-4,. Besides, Lower corrosion weight gain is obtained in the cladding tubes with decreasing annealing temperature, which correlates well with the smaller size of second phase particles. The underlying mechanism was discussed. The results in this study will be used as a guide for the material processing design of CZ1 alloy.

Research on Nodular Corrosion Resistance of N36 Zirconium Alloy at 500°C

2013 ◽  
Author(s):  
Liang Chen ◽  
Zhongbo Yang ◽  
Zhi Miao ◽  
Xun Dai ◽  
Chao Sun
Keyword(s):  
Corrosion Resistance ◽  
Spectroscopic Analysis ◽  
Volume Fraction ◽  
Second Phase ◽  
Raman Spectroscopic ◽  
Laser Raman ◽  
Corrosion Kinetics ◽  
Second Phase Particles ◽  
Electronic Microscope ◽  
Better Than

The nodular corrosion tests of improved Zr-4 tubes and two types of N36 tubes were carried out in 500 °C, 10.3Mpa super-heated steam. The results shown corrosion resistance of N36 tubes was much better than Impr.Zr-4 tubes. Characteristics of the second-phase particles and the oxide layer formed on N36 tubes were analyzed by scanning electronic microscope. The volume fraction of t-ZrO2 in oxide was calculated by Laser-Raman spectroscopic analysis. In connection with corrosion kinetics, the effect of SPPs size and volume fraction of t-ZrO2 in oxide related to corrosion resistance was discussed. It was pointed out that nodular corrosion resistance of N36 tubes can be improved by SPPs.

Development of New Wrought Mg Alloys: Improving the Corrosion Resistance by Addition of Alloying Elements

2020 ◽  
Vol 27 ◽  
pp. 50-60
Author(s):  
Guy Ben Hamu ◽  
Polina Metalnikov
Keyword(s):  
Mechanical Properties ◽  
Corrosion Resistance ◽  
Oxide Layer ◽  
Weight Ratio ◽  
High Strength ◽  
Mg Alloys ◽  
Alloying Elements ◽  
Second Phase ◽  
Second Phase Particles ◽  
Superior Corrosion Resistance

Magnesium (Mg) alloys constitute an attractive structural material for transportation industries, due to their low density and high strength/weight ratio. However, high susceptibility to corrosion of Mg alloys limits their use. Therefore, there is a growing interest for development of new Mg alloys with good mechanical properties and superior corrosion resistance. Production of wrought Mg alloys results in enhancement of mechanical properties, whereas addition of alloying elements may result in improved corrosion behavior. In this study we distinguish the role of aluminum, zinc, tin and calcium additions on the corrosion performance of new wrought Mg alloys. Overall, addition of alloying elements resulted in precipitation of second phase particles with cathodic behavior (relatively to Mg matrix). This enhanced the micro-galvanic effects and the corrosion resistance in short periods of immersion was deteriorated. However, in longer periods of immersion the passive characteristics of the oxide layer played a significant role in improving the alloys' corrosion resistance. The contribution of each element to the oxide layer will be discussed in detail. In general, the quantities of alloying element should be sufficient to stabilize the corrosion products layer; yet as low as possible, in order to reduce the micro-galvanic effects.

Corrosion Resistance of the Eletrodeposition Nano-TiO2/Ni Composite Coating on AZ91HP Mg Alloy

2011 ◽  
Vol 306-307 ◽  
pp. 742-745
Author(s):  
Si Rong Yu ◽  
Yan Liu ◽  
Jia An Liu ◽  
Dong Sheng Yuan
Keyword(s):  
Corrosion Resistance ◽  
Composite Coating ◽  
Polarization Curve ◽  
Corrosion Test ◽  
Mg Alloy ◽  
Second Phase ◽  
Second Phase Particles ◽  
Plating Solution ◽  
Better Than

The eletrodeposition nano-TiO2/Ni composite coating on AZ91PH Mg alloy was prepared using the nano-TiO2 as the second phase particles. The corrosion resistance of the composite coating was measured by the static immerging corrosion test and the polarization curve test. The result shows that the corrosion resistance of the composite coating was better than that of Mg alloy. The corrosion resistance of the composite coating was optimal when the content of nano-TiO2 in the plating solution was 10g/l-15g/l.

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