An Improvement in Tarnish and Corrosion Resistance of 94Ag-4Zn-Cu Alloys with Sn Addition

2014 ◽  
Vol 894 ◽  
pp. 138-142 ◽  
Author(s):  
Jirutthitikalpongsri Hirunyagird ◽  
Gobboon Lothongkum ◽  
Ekasit Nisaratanaporn
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Test ◽  
Single Phase ◽  
Corrosion Current ◽  
Eutectic Structure ◽  
Test Results ◽  
High Solubility ◽  
Cu Alloys ◽  
The Matrix ◽  
Tin Content

The tarnish and corrosion resistance of 94Ag-4Zn-Cu-Sn alloys and Ag-5.89Sn alloy compared with Ag-5.95Cu alloy were investigated. The tarnish results show that the DE* value of Ag-5.95Cu alloy is higher than those of 94Ag-4Zn-Cu-Sn alloys and Ag-5.89Sn alloy due to the sulfide formations such as Ag2S, Cu2S and CuS. The DE* value significantly decreases with increasing tin content. This is attributed to the matrix enrichment of tin which protects the sulfur reaction on surface. From corrosion test results, 94Ag-4Zn-Cu-Sn alloys and Ag-5.89Sn alloy provide the noble shift in the corrosion potentials and pitting potentials but the negative shift in the corrosion current density compared with Ag-5.95Cu alloy. Corrosion rate of 94Ag-4Zn-Cu-Sn alloys and Ag-5.89Sn alloy decrease markedly compared with Ag-5.95Cu alloy because it depends on the alloying elements and the microstructural changes. Due to high solubility of zinc and tin, the microstructures of tin-rich alloys consist of the higher portion of single phase and less eutectic structure than that of Ag-5.95Cu alloy.

scholarly journals Effect of Ca Element on Microstructure and Corrosion Behavior of Single-Phase Mg–Sc Alloy

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 93
Author(s):  
Cheng Zhang ◽  
Cheng Peng ◽  
Jin Huang ◽  
Yanchun Zhao ◽  
Tingzhuang Han ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Corrosion Test ◽  
Single Phase ◽  
Phase Particle ◽  
Test Results ◽  
Corrosion Product Film ◽  
Product Film ◽  
Protective Performance ◽  
Scanning Electron

The effect of Ca on the microstructure and corrosion behavior of a single-phase Mg–Sc alloy was investigated. The microstructure was characterized by optical microscopy and scanning electron microscopy. Corrosion behavior was measured by hydrogen evolution tests and electrochemical measurements. With the addition of microalloyed Ca, the grain size of Mg-0.3Sc alloy is refined and the Mg2Ca phase particle is precipitated. The corrosion test results reveal that the addition of microalloyed Ca is beneficial to the corrosion resistance of Mg-0.3Sc single-phase alloy, which is related to the grain refinement and the protective performance of the corrosion product film. As the content of Ca increases, the corrosion resistance of the alloy first increases and then decreases, which is mainly related to the microstructure of the alloy.

Effect of ECAP Pass on Corrosion Behavior of High-Al Content Magnesium Alloys

2013 ◽  
Vol 747-748 ◽  
pp. 270-275
Author(s):  
Qiang Fan ◽  
Wei Liang ◽  
Li Ping Bian ◽  
Man Qing Cheng
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Behavior ◽  
Performance Test ◽  
Corrosion Current ◽  
Second Phase ◽  
Al Content ◽  
Microstructure Observation ◽  
Angular Pressing ◽  
The Matrix ◽  
High Al Content

In view of low strength and poor corrosion resistance of Mg alloys, a Mg-12Al-0.7Si alloy was designed, fabricated and subjected to equal channel angular pressing (ECAP) in order to refine the microstructure. Microstructure observation and electrochemical performance test were conducted to investigate the influence of the microstructural variation subjected to multi-pass ECAP processing on the corrosion behavior of the alloy. The results showed that both α-Mg matrix and β-Mg17Al12of the alloy were significantly refined after processing for different passes (2,4,6,8) through route BC, and the 4-pass ECAPed alloy in 3.5% NaCl solution presents the lowest weight loss, lower corrosion current and higher corrosion potential in the polarization curves. The reason for high corrosion resistance of 4-pass ECAPed alloy and the effects of grain size of the matrix and the particle size, distribution of second phase and dynamic precipitates on corrosion behavior of the alloy were discussed.

Effects of Heat Treatment and Alloying of Spheroidal Graphite Cast Iron on Corrosion Resistance in Aqueous Environment

2004 ◽  
Vol 449-452 ◽  
pp. 533-536
Author(s):  
M. Aoyama ◽  
K. Tahashi ◽  
K. Matsuno
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Cast Iron ◽  
Current Density ◽  
Electrode Potential ◽  
Corrosion Current ◽  
Spheroidal Graphite ◽  
Spheroidal Graphite Cast Iron ◽  
Graphite Cast Iron ◽  
The Matrix

The present study examined the effects of heat treatment and the addition of Cu-Ni alloy on the corrosion resistance of the matrix of spheroidal graphite cast iron in aqueous environments. Test materials of white cast iron and carbon steel were used for comparison with spheroidal graphite cast iron. The alloy spheroidal graphite cast iron that added Cu and Ni was prepared. The spheroidal graphite cast iron was subjected to three kinds of heat treatment to adjust the matrix: annealing, oil quenching, and austemper heat treatment. In electrochemical tests, measurements of corrosion electrode potential and cathode and anode polarization were used. The following was clarified from the relationship between the electrode potential and current density of each of the materials in each of the solution. The alloy spheroidal graphite cast iron had a high corrosion electrode potential owing to the addition of Cu-Ni, and tended to have a low corrosion current density. This demonstrates that in any of the materials having a matrix adjusted by heat treatment, the addition of Cu-Ni increased the corrosion resistance. The corrosion current density was highest in a sulfuric acid environment.

Fast Electroless Ni-P Coating on AM60 Magnesium Alloy at Low Bath Temperature

2011 ◽  
Vol 418-420 ◽  
pp. 756-759 ◽  
Author(s):  
Guo Bing Mao
Keyword(s):  
Growth Rate ◽  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Electroless Plating ◽  
Corrosion Test ◽  
Bath Temperature ◽  
Test Results ◽  
Electroless Ni

The Ni-P coatings were deposited on AM60 magnesium alloy by electroless plating process without or with accelerators. Without accelerators, the deposition rate is slow and required high bath temperature to obtain compact coating. There have many defects on the surface of the Ni-P coatings which deposited at high bath temperature. The composite accelerators were introduced into the bath for improving the growth rate and the quality of the Ni-P coating. Uniform, with no pores or cracks, “cauliflower-like” structure and complete Ni-P coatings were deposited only taken 20 min with additives at low bath temperature. The XRD result indicates that the structure of the Ni-P coating is amorphous nickel. The corrosion test results indicated that the corrosion resistance of this coated AM60 magnesium alloys increases distinctly as compared to bare alloys.

Effects of Destabilisation Heat Treatment on Microstructure, Hardness and Corrosion Behaviour of 18wt.%Cr and 25wt.%Cr Cast Irons

2015 ◽  
Vol 658 ◽  
pp. 76-80 ◽  
Author(s):  
Amporn Wiengmoon ◽  
Torranin Chairuangsri ◽  
John T.H. Pearce
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Corrosion Behaviour ◽  
Eutectic Structure ◽  
Air Cooling ◽  
Cast Irons ◽  
Eutectic Carbides ◽  
The Matrix ◽  
Superior Corrosion Resistance ◽  
Dendritic Austenite

Effects of destabilisation heat treatment on microstructure, hardness and corrosion resistance of 18wt.%Cr and 25wt.%Cr irons have been investigated. The as-cast samples were heat-treated by destabilisation at 1000°C for 4 hour and then air cooling. The microstructure was investigated by light microscopy and scanning electron microscopy. The results show that the as-cast microstructure in 18wt.%Cr iron consists of pearlite, formed by decomposition of primary dendritic austenite, plus eutectic structure. In the 25wt.%Cr iron with lower hardness, the microstructure consists of primary dendritic austenite plus eutectic structure. The austenite had partly transformed to martensite, especially at areas adjacent to eutectic carbides. After destabilisation, the microstructure of both irons consists of eutectic and secondary carbides in a martensite matrix giving increased hardness. It was found that corrosion resistance of the irons was improved after destabilisation. The 25wt.%Cr showed superior corrosion resistance than the 18wt.%Cr iron due to greater residual Cr in the matrix to encourage passivity.

Influence of Triethylamine Inhibitor Addition on the Sealing Process of 6063 Al Alloy

2012 ◽  
Vol 538-541 ◽  
pp. 230-234
Author(s):  
Hui Cheng Yu ◽  
Xiao Xiao Huang ◽  
Yan Yan Han ◽  
Dong Ping Wei
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Potential ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Al Alloy ◽  
Test Results ◽  
Electrochemical Test ◽  
Tafel Polarization ◽  
Electrochemical Parameters ◽  
6063 Al Alloy

To improve the corrosion resistance of Al alloy, triethylamine (TEN) was added into the sealing solutions. Tafel polarization and electrochemical impedance spectroscopy(EIS) techniques were used to investigate the electrochemical behavior of sealing coatings formed in different concentrations of triethylamine(TEN). Compared with the coatings with D. I. water and the bare aluminum alloy, the polarization curves show that the sealing coatings formed in 5.0 – 7 .0 g.L-1 triethylamine (TEN) solutions have more positive corrosion potential (Ecorr) and pitting corrosion potential (Epit), and lower corrosion current density (icorr). Electrochemical parameters of EIS indicate that the sealing coatings have higher corrosion resistance. The electrochemical test results show the prepared sealing coatings have better corrosion resistance.

Accelerating Corrosion Test Study on Galvanized Q345 Steel

2010 ◽  
Vol 139-141 ◽  
pp. 314-320 ◽  
Author(s):  
Xiao Hua Yang ◽  
Ding Zhang ◽  
Yong Zhang
Keyword(s):  
Corrosion Resistance ◽  
Pitting Corrosion ◽  
Corrosion Test ◽  
Turning Point ◽  
Zinc Coating ◽  
Uniform Corrosion ◽  
Matrix Metal ◽  
Test Study ◽  
The Matrix ◽  
Better Than

Galvanized Q345 steel specimens were accelerating corroded with accelerating environment spectrum for equivalent 1, 3, 4 and 5 years, and then its corrosion behavior was studied based on macro corrosion appearances, micro corrosion appearances, weight loss, pits depth and fatigue strength. The results show that, i because the zinc coating can protect the matrix metal from corroding, the corrosion resistance of galvanized Q345 is much better than Q345; ii between the 1st year and the 4th year, pitting corrosion is dominative, and after the 4th year, the corrosion form transforms from pitting corrosion to uniform corrosion; iii after corrosion for 5 years, the zinc coating was not destroyed completely, and with the turning point of the 4th year, the corrosion rate of the zinc coating becomes higher firstly and then gets lower, which agrees with previous study.

Mechanical Properties of Hypo/Hyper-Eutectic Al-Si Bi-Metal Composite Parts Prepared by Thixo-Forging

2012 ◽  
Vol 192-193 ◽  
pp. 95-100
Author(s):  
Tian Bao Li ◽  
Zhao Yang ◽  
Bing Li ◽  
Yu Long Ye
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Tensile Test ◽  
Eutectic Structure ◽  
Metal Composite ◽  
Test Results ◽  
Metal Composites ◽  
Average Hardness ◽  
Composite Interface ◽  
The Matrix

Hypo/hyper-eutectic Al-Si bi-metal composite parts were prepared by the strain-induced melt activated (SIMA) thixo-forging. The interfaces of the bi-metal composites were observed using OM, and SEM. The tensile strength and hardness of the matrix alloys and the bonding strength at the interface were assessed by tensile test and micro-indent test. Results show that the eutectic structure joined together on the interface under the pressure. However, there are some defects such as holes and impurities were found near the interface. The tensile test samples were broken in Al-20 wt. % Si matrix. The bonding strengths at the interfaces were higher than 80 MPa. Results show that the hardness gradually increasing from 55 HV in Al-7 wt. % Si alloy to 180 HV in Al-20 wt. % Si alloy, which demonstrate the composite interface transited smoothly. The composite interface has an average hardness of 80 HV.

Effects of SnCl4 Concentration on the Properties of Electroless Deposited Ni-Sn-P Coatings

2014 ◽  
Vol 989-994 ◽  
pp. 403-406
Author(s):  
Xi Ran Wang ◽  
Wen Tao Wang ◽  
Bin Yang
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Deposition Rate ◽  
Corrosion Current ◽  
Polarization Curves ◽  
Surface Appearance ◽  
Positive Direction ◽  
Before And After ◽  
Tin Content

In this paper, the influence of SnCl4concentration on deposition rate, tin content, corrosion resistance and surface appearance of the coating are researched respectively. The results show that SnCl4concentration is increased, deposition rate is increased, then reduced. Tin content in the Ni–Sn–P coatings is increased with increasing SnCl4concentration in the solutions. However, Ni and P contents in the coating is decreased slightly. The microhardness of plating before and after heat treatment is above 500HV. The hardness will be improved a little after heat treatment. With increasing SnCl4concentration, the polarization curves slightly move to positive direction and decrease corrosion current, which shows that the introduction of tin tends to enhance resistance corrosion of the coating. When SnCl4concentration is up to 30g/L, resistant corrosion of the films presents a drop various degrees. The deposits is smooth and uniformity, smooth by SEM and the content of tin is 2.5 to 4.1 percent by EDS.

Effect of Sn Addition on the Corrosion Performance of Cast X-52 in H2S-Containing Environment at 60°C

2013 ◽  
Vol 743-744 ◽  
pp. 607-612 ◽  
Author(s):  
Hong Liang Lin ◽  
Jian Qiu Wang ◽  
En Hou Han
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Rate ◽  
Electrochemical Impedance ◽  
Corrosion Current ◽  
Corrosion Performance ◽  
Positive Role ◽  
Surface Corrosion ◽  
The Matrix ◽  
The Relationship ◽  
Small Content

The electrochemical behavior of cast X-52 with different Sn content ranging from 0 to 1 wt. % was investigated using the methods of potentiodynamic test, electrochemical impedance spectroscopy (EIS). The immersion tests involved to examine the relationship between Sn addition and corrosion performance of cast X-52. In addition, the morphology and the compositions of surface corrosion products were analyzed using scanning electron microscope (SEM)/ energy dispersive spectroscopy (EDS). Potentiodynamic polarization curves showed that the presence of Sn decreased the corrosion current density. EIS indicated that Sn-containing steels had higher polarization resistances. These results confirmed that Sn played a positive role in reducing corrosion rate in H2S-containing environment. However, the corrosion resistance decreased with increasing Sn addition. It was proved that Sn improved the corrosion resistance with only a small content and large amount of Sn might lead to an advance of the pit due to occurrence of more acidification. Moreover, a continuous inner O-rich layer adherent to the matrix was found for Sn-addition samples, which lead to a decrease of corrosion rate due to its compact characteristic, compared with porous sulfide formed on the outer surface.

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