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.

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.

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.

Corrosion Resistance of Mg Alloy with High Zn Concentration Including Impurity Cu

2021 ◽  
Vol 1016 ◽  
pp. 592-597
Author(s):  
Masato Ikoma ◽  
Taiki Morishige ◽  
Tetsuo Kikuchi ◽  
Ryuichi Yoshida ◽  
Toshihide Takenaka
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Mg Alloys ◽  
Mg Alloy ◽  
Second Phase ◽  
Transportation Industry ◽  
Primary Metal ◽  
Cu Content ◽  
Zn Concentration ◽  
Lower Corrosion Rate

Mg alloys are very attractive materials for transportation industry due to their toughness and lightness. Recycling Mg alloys is desired for energy saving that otherwise would be required to produce its primary metal. However, secondary produced Mg tends to contain a few impurity elements that deteriorate its corrosion resistance. For example, contamination of Mg alloy by Cu induces second phase of Mg2Cu and it works as strong cathode, resulting in the corrosion rate rapidly increasing. It was previously reported that the corrosion resistance of Mg with impurity Cu was remarkably improved by addition of alloying element Zn. Addition of Zn into Mg formed MgZn2 phase and incorporated Cu into MgZn2 phase instead of Mg2Cu formation. In this way, since Zn serves to improve the corrosion resistance of Mg, Mg alloy with high Zn concentration may form a lot of MgZn2 and may have better corrosion resistance even with high Cu concentration. In this work, the corrosion behavior of Mg-6mass%-1mass%Al (ZA61) with different Cu content up to 1mass% was investigated. As a result, ZA61-1.0Cu had much lower corrosion rate compared to Mg-0.2%Cu and the corrosion rate was almost the same as that of pure Mg.

Wear Properties of Y-TZP Ceramics Dispersed with Second Phase Particles

2008 ◽  
Vol 368-372 ◽  
pp. 744-747
Author(s):  
Xiao Ping Liang ◽  
Shao Bo Xin ◽  
Xiao Hui Wang ◽  
Zheng Fang Yang
Keyword(s):  
Mechanical Properties ◽  
Wear Resistance ◽  
Mass Fraction ◽  
Normal Load ◽  
Roller Bearing ◽  
Second Phase ◽  
Wear Properties ◽  
Wear Rates ◽  
Second Phase Particles ◽  
Better Than

The wear properties of ADZ (alumina dispersed in Y-TZP) and MDZ (mullite dispersed in Y-TZP) were investigated by using a ring-on-block tribometer. The results showed that for Y-TZP ceramic, the addition of alumina phase (with 10-20% in mass fraction) leads to an improved wear resistance. With the increase of the normal load, the wear rates of ADZ ceramics increase. Under low and medium normal load (100N and 300N), the wear resistance is controlled by the hardness of ceramics, and under high normal load (500N) the fracture toughness is obviously contributed to the wear resistance of the ceramics. For MDZ ceramic, the wear resistance of 15MDZ (15wt% mullite dispersed in Y-TZP) is better than that of 20 MDZ (20wt% mullite) under the normal load from 100 N to 500 N. The mechanical properties of 15MDZ are worse than that of Y-TZP ceramic, but the wear resistance is enhanced due to the action of “needle roller bearing” of the fractured rod-like mullite particles.

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.

Cavity of Al-Cu-Mg Alloy during Superplastic Deformation

2007 ◽  
Vol 551-552 ◽  
pp. 645-650
Author(s):  
Min Wang ◽  
Hong Zhen Guo ◽  
Y.J. Liu
Keyword(s):  
Strain Rate ◽  
Grain Boundaries ◽  
Superplastic Deformation ◽  
Room Temperature ◽  
Mg Alloy ◽  
Deformation Condition ◽  
Second Phase ◽  
Rate Condition ◽  
Second Phase Particles ◽  
Strain Rate Condition

According to the characteristic of appearing cavitation in the metals during superplastic deformation, the influence of strain rate on cavity evolvement, the influence of cavity on superplastic deformation capability, and the formation, development process of cavity were investigated for Al-Cu-Mg alloy (i.e. coarse–grained LY12). The results show that: ①The pore nucleation occurs not only at triangle grain boundaries, but also along nearby the second phase particles, and even within grains. The cavities at the triangle grain boundaries are present in V-shape, others near the second phase particles and within grains are present in O-shape. These cavities may result from disharmony slippage of grain boundaries. ②The tendency of cavity development decreases with increasing of strain-rate. In lower strain-rate condition, though Al-Cu-Mg alloy has better superplasticity, many big cavities in the specimen may reduce the room temperature properties of the alloy. In higher strain-rate condition, Al-Cu-Mg alloy has certain superplasticity and room temperature properties as well as few cavities forming. By analyzing, viscous layer on grain boundaries is very thin and grain sizes can be refined during their extruding and rotating each other in higher strain-rate superplastic deformation condition. ③Growth and coalescence of cavity are the main reason of the superplastic fracture of Al-Cu-Mg alloy. And small and a certain amount of cavities with dispersion and independence state are very useful to crystal boundary slippage.

Corrosion resistance of layer-by-layer assembled polyvinylpyrrolidone/polyacrylic acid and amorphous silica films on AZ31 magnesium alloys

RSC Advances ◽  
2016 ◽  
Vol 6 (68) ◽  
pp. 63107-63116 ◽  
Author(s):  
Lan-Yue Cui ◽  
Rong-Chang Zeng ◽  
Shuo-Qi Li ◽  
Fen Zhang ◽  
En-Hou Han
Keyword(s):  
Corrosion Resistance ◽  
Composite Coating ◽  
Magnesium Alloys ◽  
Amorphous Silica ◽  
Polyacrylic Acid ◽  
Dip Coating ◽  
Mg Alloy ◽  
Layer By Layer ◽  
Silica Films ◽  
Az31 Mg Alloy

A layer-by-layer (LbL)-assembled composite coating containing SiO2 and a biocompatible polyvinylpyrrolidone (PVP) and polyacrylic acid (PAA) multi-layer, designated as SiO2/(PVP/PAA)5, was prepared on AZ31 Mg alloy via dip-coating.

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