scholarly journals THE EFFECTS OF TERNARY ALLOYING ADDITIONS ON THE CORROSION RESISTANCE OF EPSILON-PHASE URANIUM-ZIRCONIUM ALLOYS

1956 ◽  
Author(s):  
J.E. Reynolds ◽  
W.E. Berry ◽  
H.R. Ogden ◽  
R.S. Peoples ◽  
R.I. Jaffee
Keyword(s):  
Corrosion Resistance ◽  
Zirconium Alloys ◽  
Alloying Additions ◽  
Ternary Alloying

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.

Effect of Platinum Elements Additions on the Active Dissolution of Plastic Chromium in Sulfuric Acid

CORROSION ◽  
1984 ◽  
Vol 40 (3) ◽  
pp. 134-138 ◽  
Author(s):  
N. D. Tomashov ◽  
G. P. Chernova ◽  
E. N. Ustinsky
Keyword(s):  
Corrosion Resistance ◽  
Sulfuric Acid ◽  
Anodic Dissolution ◽  
Cathodic Polarization ◽  
Active State ◽  
Alloying Elements ◽  
Active Dissolution ◽  
Alloying Additions ◽  
Blocking Mechanism

Abstract Alloys based on plastic chromium with 0.1 to 0.4 mass % Ru, Pd, Ir, or Pt were investigated in 40% sulfuric acid in active state under cathodic polarization (−0.175 V). All of the studied additions of alloying elements are responsible for the reduced anodic dissolution of chromium. The corrosion resistance of alloys depends on the concentration and nature of the alloying additions. Two mechanisms decelerating the active dissolution of the cathode-modified chromium have been established, i.e., blocking mechanism (cathodic component atoms block the active points in the lattice) and screening mechanism (cathodic component, while getting crystallized on the surface, partly screens the latter).

scholarly journals Impact of Bi and Sn on Microstructure and Corrosion Resistance of Zinc Coatings Obtained in Zn-AlNi Bath

Materials ◽  
2020 ◽  
Vol 13 (17) ◽  
pp. 3788
Author(s):  
Henryk Kania ◽  
Mariola Saternus ◽  
Jan Kudláček
Keyword(s):  
Corrosion Resistance ◽  
Salt Spray ◽  
Neutral Salt ◽  
Energy Dispersion Spectroscopy ◽  
Humid Atmosphere ◽  
Alloying Additions ◽  
Electrochemical Parameters ◽  
Zinc Coatings ◽  
Structural Research ◽  
The Impact

The paper presents results of studies on the impact of bismuth and tin additions to the Zn-AlNi bath on microstructure and corrosion resistance of hot dip galvanizig coatings. The structure at high magnifications on the top surface and cross-section of coatings received in the Zn-AlNiBiSn bath was revealed and the microanalysis EDS (energy dispersion spectroscopy) of chemical composition was determined. The corrosion resistance of the coatings was tested relatively in a neutral salt spray test (NSS), and tests in a humid atmosphere containing SO2. Electrochemical parameters of coatings corrosion were determined. It was found that Zn-AlNiBiSn coatings show lower corrosion resistance in comparison with the coatings received in the Zn-AlNi bath without Sn and Bi alloying additions. Structural research has shown the existence of precipitations of Sn-Bi alloy in the coating. It was found that Sn-Bi precipitations have more electropositive potential in relation to zinc, which promotes the formation of additional corrosion cells.

Simultaneous Reduction of Wear and Corrosion of Titanium, Magnesium and Zirconium Alloys by Surface Plasma Electrolytic Oxidation Treatment

2008 ◽  
Vol 38 ◽  
pp. 27-35 ◽  
Author(s):  
H.M. Nykyforchyn ◽  
V.S. Agarwala ◽  
M.D. Klapkiv ◽  
V.M. Posuvailo
Keyword(s):  
Corrosion Resistance ◽  
Plasma Electrolytic Oxidation ◽  
Synthesis Method ◽  
Zirconium Alloys ◽  
Ceramic Coatings ◽  
Oxide Ceramic ◽  
Wear And Corrosion ◽  
Electrolytic Oxidation ◽  
Wear And Corrosion Resistance ◽  
Plasma Electrolytic

Titanium, magnesium and zirconium alloys are widely used in industrial applications, which require high wear and corrosion resistance. However current methods of improving these properties often do not satisfy the requirements of service and functional properties. An alternative approach is the application of oxide-ceramic coatings using high temperature process. The coatings are applied by spark discharge plasma in the metal-electrolyte system at high voltages - PEO (plasma electrolytic oxidation) as an oxide synthesis method. This method has shown good results for aluminium alloys and with good prospects to be used for titanium, magnesium and zirconium alloys. Development of PEO technology to improve the wear and corrosion resistance of titanium, magnesium and zirconium alloys is discussed in this paper. It describes the methods for obtaining the required layer-thickness for a specified hardness, porosity, wear and corrosion resistance, sets up the optimal process parameters (voltage/current) by taking the relation of anodic to cathodic currents into account, and establishing the electrolyte content of different dopants.

Site Occupancy Determination by ALCHEMI of Nb and Cr in γ-TiAl and Their Effects on the a to γ Massive Phase Transformation

1999 ◽  
Vol 589 ◽  
Author(s):  
T.M. Miller ◽  
L. Wang ◽  
W.H. Hofmeister ◽  
J.E. Wittig ◽  
I.M. Anderson
Keyword(s):  
Solid State ◽  
Rapid Solidification ◽  
Titanium Aluminides ◽  
Site Occupancy ◽  
Solidification Structure ◽  
Two Phase ◽  
Alloying Additions ◽  
Massive Phase ◽  
Ternary Alloying ◽  
Solid State Cooling

AbstractAtom location by channeling enhanced microanalysis (ALCHEMI) has been used to characterize the site distributions of Nb and Cr alloying additions in the L10-ordered γ phase of ternary titanium aluminides. Two alloys, Ti50Al48Cr2 and Ti50A148Nb2, were processed by furnace cooling from 1300°C (within the α-γ two phase field) as well as by rapid solidification using twin-anvil splat quenching of electromagnetically levitated and undercooled samples. ALCHEMI studies of furnace cooled samples yield results generally consistent with those in the published literature. Nb alloying additions are found to partition exclusively to the ‘Ti’ sublattice, while Cr alloying additions exhibit an ‘Al‘ sublattice preference. However, a higher degree of disorder can be achieved with rapid solidification and high solid state cooling rates (105-106 K/s). Significant distribution of the ternary elements between the ‘Ti’ and ‘Al‘ sublattices has been measured in the splat quenched samples, with up to 12% of the Nb atoms occupying the ‘Al‘ sublattice and the fraction of Cr atoms on the ‘Ti’ sublattice doubling to ∼30%. Rapid solidification of TiAl produces an equiaxed hexagonal α phase solidification structure that transforms in a massive fashion to the tetragonal γ phase. Although the amount of massively transformed γ is dependent upon the solid state cooling rate, ternary alloying additions can more strongly influence the transformation kinetics. The Nb-modified alloy exhibits significant amounts of the massively tranformed γ, similar to the Ti52Al48 binary alloy, whereas little massively transformed γ is observed in the Cr-modified alloy. These results can be correlated with the relative atomic size, lattice distortion, and sublattice site occupancy of Nb and Cr in the L10 unit cell.

Evaluation of Coefficient of Thermal Expansion of Zirconium by Using Dilatometer & Ansys

2018 ◽  
Vol 1148 ◽  
pp. 128-135
Author(s):  
Repalle Jithendra Kumar ◽  
B.V.S. Raghu Vamsi ◽  
T. Siva Krishna ◽  
D. Tarun ◽  
M. Kamal Tej
Keyword(s):  
Thermal Expansion ◽  
Corrosion Resistance ◽  
Thermal Properties ◽  
Nuclear Reactors ◽  
Coefficient Of Thermal Expansion ◽  
Zirconium Alloys ◽  
Nuclear Technology ◽  
High Corrosion Resistance ◽  
Weight Percentage ◽  
Water Reactors

Zirconium alloys are solid solutions of zirconium or other metals. Zirconium has very low absorption cross-section of thermal neutrons. Zirconium has high corrosion resistance, ductility and hardness. Zirconium is mainly used as a good refractory metal. Zirconium can be manufactured by using standard fabrication techniques. In the present scenario zirconium alloys are used in water reactors for the cladding of fuel rods in nuclear reactors in nuclear technology. We use the composition of zirconium alloys as more than 94.5 weight percentage of zirconium and less than 2.45 weight percentage of copper which are added to improve mechanical, thermal properties and corrosion resistance. This paper first focuses on the study of thermal properties of Zirconium. And this particularly concentrated on variation of Coefficient of Thermal Expansion by varying temperatures by using Dilatometer and as well as ANSYS

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