INFLUENCE OF SURFACTANTS ON THE CORROSION PROPERTIES OF CHROMIUM-FREE ELECTROLESS NICKEL DEPOSIT ON MAGNESIUM ALLOY

2012 ◽  
Vol 19 (03) ◽  
pp. 1250025 ◽  
Author(s):  
JOTHI SUDAGAR ◽  
RUAN DEWEN ◽  
YAQIN LIANG ◽  
RASU ELANSEZHIAN ◽  
JIANSHE LIAN
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Electroless Nickel ◽  
Corrosion Current ◽  
Immersion Test ◽  
Electrochemical Polarization ◽  
Nickel Deposit ◽  
Corrosion Properties ◽  
Positive Direction ◽  
Polarization Test

Influence of surfactants on the corrosion properties of chromium-free electroless nickel deposit were investigated on AZ91D magnesium alloy. The corrosion tests were carried out by immersion test (1 M HCl) and electrochemical polarization test (3.5 wt% NaCl ). The surfactants in the electroless nickel bath increases the corrosion resistance properties of the deposit on the magnesium alloy. In addition, smoothness and amorphous plus nano-crystalline phase were increased and accounted for the significant corrosion resistance. As a consequence, the corrosion potential moved towards the positive direction and the corrosion current density decreased. The immersion tests also provided the same trend as that of electrochemical polarization test. On the whole, the study concluded that corrosion resistance was enhanced by including a surfactant in the electroless deposits on magnesium alloy.

Effect of Ti Addition on Corrosion Properties of As-Cast and Hot-Rolled AM60 Magnesium Alloys

2017 ◽  
Vol 750 ◽  
pp. 113-117
Author(s):  
Yavuz Sun ◽  
Nazif Ugur Aydın ◽  
Yunus Turen ◽  
Hayrettin Ahlatci ◽  
Huseyin Zengin
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Immersion Test ◽  
Electrochemical Analysis ◽  
Electrochemical Test ◽  
Corrosion Properties ◽  
Homogenization Treatment ◽  
Corrosion Behaviors ◽  
Hot Rolled ◽  
Ti Addition

This study investigates the effect of Ti addition (0, 0.2, 0.5, 1wt%) on corrosion resistance of as-cast and hot rolled AM60 magnesium alloy. Corrosion behaviors were investigated by immersion tests and electrochemical analysis. The results showed that Ti addition altered the microstructure of as-cast AM60 magnesium alloy by decreasing the amount of β-Mg17Al12 eutectic phase. Homogenization treatment resulted in the dissolution of the most of the β-Mg17Al12 phases. Homogenized samples exhibited the lowest corrosion rate in immersion test while the best corrosion resistance was found for hot-rolled samples in electrochemical test. In hot-rolled state, Ti addition led to a slight change in the corrosion resistance of AM60 magnesium alloy.

Influence of Current Density on Structure and Performance of Micro-Arc Oxidation Coatings on AZ31 Magnesium Alloy

2011 ◽  
Vol 189-193 ◽  
pp. 562-566 ◽  
Author(s):  
Mei Yang ◽  
Zheng Lei ◽  
Xiao Hong Wang ◽  
Ping Wang ◽  
Jun Yang
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Current Density ◽  
Adhesion Force ◽  
Water Solution ◽  
Corrosion Current ◽  
Az31 Magnesium Alloy ◽  
Positive Direction ◽  
Micro Arc Oxidation ◽  
And Performance

In the Na2SiO3-NaOH-C3H8O3electrolyte system,the micro-arc oxidation (MAO) coatings were prepared on AZ31 magnesium alloy when J=2A/dm2,4A/dm2,8A/dm2and 12A/dm2.The relations of current density with microstructure and performance of the MAO coatings on AZ31 were studied by means of SEM, XRD, HVS-1000 micro Vicker, MFT-4000 Scratch Tester and electro-chemical method. The results show that when current density increases,the thickness,growth rate,micro-hardness and the contents of MgO and Mg2SiO4of MAO coatings increase,but the adhesion force between MAO coating and substrate decreases, the millipores and the roughness become larger.The corrosion resistance of MAO coatings increases firstly and then decreases with the increasing current density.The corrosion resistance of MAO coating,which J=6 A/dm2,is the best in 4.5% NaCl water solution,whose corrosion current density reduces by 3 orders of magnitude, and corrosion potential increases 1078mV in positive direction.

A Study on the Electroless Ni–P Deposition of AM60B Magnesium Alloy without HF in Bath

2014 ◽  
Vol 633-634 ◽  
pp. 879-882 ◽  
Author(s):  
Jing Dong Qiu ◽  
Su Qiu Jia
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Current Density ◽  
Corrosion Current Density ◽  
Corrosion Potential ◽  
Electroless Nickel ◽  
Corrosion Current ◽  
Dense Structure ◽  
Electroless Ni

Based on the traditional direct electroless nickel methods, chemical baths are improved by removing HF. Examinations have been carried out on the Ni-P deposited on the interlayer for morphology, composition and corrosion-resistance by SEM, EDS, XRD and other instruments. A Ni-P film with fine and dense structure was obtained on the AM60B magnesium alloy. It exhibits lower corrosion current density and more positive corrosion potential than the substrate.

Research on Corrosion Resistance of AZ91D Magnesium Alloy Coated with Epoxy Resin

2011 ◽  
Vol 686 ◽  
pp. 292-299
Author(s):  
Yong Gang Li ◽  
Ying Hui Wei ◽  
Li Feng Hou ◽  
Yun Tian ◽  
Li Jing Yang
Keyword(s):  
Corrosion Resistance ◽  
Magnesium Alloy ◽  
Adhesion Force ◽  
Die Casting ◽  
Corrosion Current ◽  
Scratch Test ◽  
Organic Coating ◽  
Thin Wall ◽  
Scanning Method ◽  
Az91d Magnesium Alloy

The corrosion resistance of a 1~2mm thick AZ91D magnesium alloy die-casting coated with epoxy varnish after phosphatizing was tested. Zinc phosphating solution was used. In the experiment, uniform paint was obtained by dipping method. Scratch test showed that the adhesion force between the coating and matrix is excellent. Within the test range the optimal phosphating temperature and time are 50°C and 1 min tested by dynamic potential scanning method. With the organic coating the corrosion current density decreased 3 orders of magnitude, the polarization resistance increased 3 orders of magnitude. The coated specimens were immersed in10% H2SO4, 10% NaOH and acetone for 10 days, respectively. The results showed that blistering did not occur on the paint films. This work illustrated that the simple zinc phosphating process combined with simple organic coating can meet the corrosion resistance requirements of thin-wall die casting magnesium components that require higher quality appearance.

Structural Characterization and Corrosion Properties of BTESPT Silane Films on Surface of 2024-T6 Aluminium Alloy

2007 ◽  
Vol 546-549 ◽  
pp. 1111-1116 ◽  
Author(s):  
Ming An Chen ◽  
Xuan Xie ◽  
Guo Fu Xu ◽  
Hui Zhong Li ◽  
Xin Ming Zhang
Keyword(s):  
Structural Characterization ◽  
Water Solution ◽  
Corrosion Current ◽  
Immersion Test ◽  
Alloy Sheet ◽  
Al Alloy ◽  
Entire Surface ◽  
Corrosion Properties ◽  
The Matrix

2024-T6 Al alloy sheet s were modified by bis-[triethoxysilylpropyl] tetrasulfide (BTESPT) silane film to improve the corrosion resistance. Fourier-Transform Reflection Absorption (FTIR-RA) spectroscopy was used for structural characterization of BTESPT silane film formed on surface of the sheet. Potentiodynamic polarization and immersion test in 3.5% NaCl solution were used for evaluating the corrosion performances of the silane film. The results showed that the film formed after curing at 120 °C for 40 min was cross-linked through Si-O-Si and that it was covered on the entire surface of the sheet. The content of elements S and Si on the Al2CuMg particles is a little higher that of on the matrix. The strong peak at 1032 cm-1 indicated that the film was linked to the sheet by Si-O-Al. Compared to the untreated case, the corrosion current density of the sheet treated with the silane film was reduced by close to 2 orders. Treatment of BTESPT silane can provide about 670 h protection of corrosion for the sheet in 3.5% NaCl water solution.

Study of Hardness and Corrosion Resistance of Electroless Ni-P-TiO2 Composite Coatings

2017 ◽  
pp. 1303-1326
Author(s):  
Prasanna Gadhari ◽  
Prasanta Sahoo
Keyword(s):  
Corrosion Resistance ◽  
Annealing Temperature ◽  
Composite Coatings ◽  
Electroless Nickel ◽  
X Ray Diffraction ◽  
Corrosion Properties ◽  
Nickel Coatings ◽  
Nodular Structure ◽  
Grey Relational ◽  
Electroless Ni

Electroless nickel coatings are widely popular in various industrial sectors due to their excellent tribological properties. The present study considers optimization of coating parameters along with annealing temperature to improve microhardness and corrosion resistance of Ni-P-TiO2 composite coatings. Grey relational analysis is used to find out the optimal combination of coating parameters. From the analysis, it is confirmed that annealing temperature of the coating has the most significant effect and amount of titanium particles in the coating has some significant effect on corrosion properties of the coating. The same trend is observed in case of combined study of corrosion behavior and microhardness. The surface morphology, phase transformation and the chemical composition are examined using scanning electron microscopy, X-ray diffraction analysis and energy dispersive analysis respectively. The Ni-P-TiO2 composite coating revealed nodular structure with almost uniform distribution of titanium particles and it turns in to crystalline structure after heat treatment.

Electroless Multilayer Coatings Used in the Protection of Thermosyphon Economizer from Corrosion

2012 ◽  
Vol 512-515 ◽  
pp. 1607-1610
Author(s):  
Yang Xu ◽  
Yong Zou ◽  
Tao Luan
Keyword(s):  
Corrosion Resistance ◽  
Single Layer ◽  
Electroless Nickel ◽  
Corrosion Current ◽  
Multilayer Coatings ◽  
Electrochemical Tests ◽  
Exhaust Temperature ◽  
Electroless Copper ◽  
Save Energy ◽  
Better Than

Economizers are widely employed in the boiler system to increase efficiency and save energy. However one prominent problem is the severe corrosion of economizer due to the decrease of the exhaust temperature of boiler. Ni–P/Cu/Ni-P multilayer coatings, which could effectively improve the corrosion resistance of the facilities in economizer, are introduced in the present work. The three-layer coatings, whose composition is Ni–P/Cu/Ni-P from substrate to surface, were prepared using dual baths (acidic hypophosphite-reduced electroless nickel bath and acidic replacement electroless copper bath). The corrosion resistance of the coatings was evaluated by porosity and electrochemical tests. The results of porosity evaluation show that all the multilayer coatings performed better than the single-layer coatings of similar thickness. Similarly, The electrochemical tests showed lower corrosion current density for the multilayer coatings in 3.5 wt.% NaCl aqueous solutions.

scholarly journals Characterization of non-metallic inclusions in corrosion -resistance nickel - based EP718 and 718 alloys by using electrolytic extraction method

2019 ◽  
Vol 121 ◽  
pp. 04004 ◽  
Author(s):  
Andrey Karasev ◽  
Ekaterina Alekseeva ◽  
Aleksey Lukianov ◽  
Pär G. Jönsson
Keyword(s):  
Corrosion Resistance ◽  
Extraction Method ◽  
Oil And Gas ◽  
Three Dimensional ◽  
Steel Production ◽  
Immersion Test ◽  
Corrosion Properties ◽  
Electrolytic Extraction ◽  
Electrochemical Tests ◽  
Metallic Inclusions

It is known that non-metallic inclusions (NMI) that are formed during steel production and heat treatment can significantly affect the properties of final steel products. Therefore, it is very important to be able to determine the content of harmful NMI in steels. Nickel-based alloys are widely used in the oil and gas recovery industry, due to a good combination of strength and corrosion properties. Earlier studies have shown that the corrosion properties in immersion test and electrochemical tests for Ni-based EP718 alloys are slightly lower than that for 718 alloys. The focus in this study was the influence of different NMI on the corrosion resistance of these alloys. The characteristics of inclusions (such as size, morphology, and chemical composition) were analysed by using the electrolytic extraction method followed by three-dimensional investigations using SEM in combination with EDS. It was found that some non-metallic inclusions in EP718 alloys significantly reduce its corrosion resistance. It was also shown that a primary dissolution of the metal matrix occurs around certain inclusions during electrolytic extraction. Based on obtained results, the corrosion active non-metallic inclusions can be determined in these Nickel-base alloys and some recommendations for optimization of their production technology can be formulated.

Tribological and Corrosive Properties of Tin/AlN Multilayer Film

2012 ◽  
Vol 560-561 ◽  
pp. 837-841
Author(s):  
Pu Hong Tang ◽  
Jie Mao ◽  
Chong You Feng
Keyword(s):  
Corrosion Resistance ◽  
Coefficient Of Friction ◽  
Gas Flow ◽  
Multilayer Film ◽  
Corrosion Current ◽  
Multilayer Films ◽  
Nitrogen Gas ◽  
Corrosion Properties ◽  
Wear Rates ◽  
The Coefficient Of Friction

TiN/AlN nanoscale multilayer films were deposited by pulsed laser ablation on silicon, with different argon and nitrogen gas flow rates. The total thickness of the TiN/AlN multilayer film was approximately 1μm. The friction and corrosion properties were studied by tribological and corrosive tests. In tribological tests, ball-on-disc was used to determine coefficients of friction and wear rates. The coefficient of friction against a Si3N4 ball varied considerably between films, as does the wear rate. The lowest coefficient of friction μ=0.97 was shown at sample 1, whereas the other three multilayer films were ranged from 1.0 to 1.5. In corrosion test, the anodic polarization characteristics were measured in a 3.5% NaCl solution at room temperature to examine the corrosion resistance. The potentiodynamic polarization measurements showed that for all the multilayer films the corrosion potential shift to higher values, and the corrosion current density decreased with increasing of nitrogen gas flow rate, which indicate a higher nitrogen partial pressures lead to a better corrosion resistance.

scholarly journals Surface Modification of Mg0.8Ca Alloy via Wollastonite Micro-Arc Coatings: Significant Improvement in Corrosion Resistance

Metals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 754
Author(s):  
Mariya B. Sedelnikova ◽  
Anna V. Ugodchikova ◽  
Tatiana V. Tolkacheva ◽  
Valentina V. Chebodaeva ◽  
Ivan A. Cluklhov ◽  
...  
Keyword(s):  
Corrosion Resistance ◽  
Corrosion Current ◽  
Biological Properties ◽  
Mineralization Process ◽  
Corrosion Properties ◽  
Oxidation Method ◽  
Significant Difference ◽  
Structure Phase ◽  
Micro Arc Oxidation ◽  
Calcium Silicates

Biodegradable materials are currently attracting the attention of scientists as materials for implants in reconstructive medicine. At the same time, ceramics based on calcium silicates are promising materials for bone recovery, because Ca2+ and Si2+ ions are necessary for the mineralization process, and they take an active part in the formation of apatite. In the presented research, the protective silicate biocoatings on a Mg0.8Ca alloy were formed by means of the micro-arc oxidation method, and the study of their morphology, structure, phase composition, corrosion, and biological properties was carried out. Elongated crystals and pores were uniformly distributed over the surface of the coatings. The coated samples exhibited remarkable anti-corrosion properties in comparison with bare magnesium alloy because their corrosion current decreased 10 times, and their corrosion resistance increased almost 100 times. The coatings did not significantly affect the viability of the cells, even without the additional dilution of the extract, and were non-toxic according to ISO 10993-5: 2009. In this case, there was a significant difference in toxicity of the pure Mg0.8Ca alloy and the coated samples. Thus, the results demonstrated that the applied coatings significantly reduced the toxicity of the alloy.

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