The formation of a hydrotalcite coating on the aluminium alloy 6060 using a spray system

Clay Minerals ◽  
2015 ◽  
Vol 50 (5) ◽  
pp. 583-592 ◽  
Author(s):  
Lingli Zhou ◽  
Henrik Friis ◽  
Melanie Roefzaad ◽  
Kasper Bondo Hansen ◽  
Sara Eisenhardt ◽  
...  

AbstractCoatings with the composition of Li-Al-NO3 hydrotalcite were formed on the Al alloy 6060 using a spray system. The coatings consist of crystals with a typical hydrotalcite structure. Dense, uniform and blade-like flakes cover completely the surface of the Al substrate. The coatings display a multi-layer structure with average thickness of ∼1000 nm. The hydrotalcite-coated samples performed better than those without coatings in salt-spray and filiform-corrosion tests, and further treatment involving sealing with a Mg acetate solution and dipping in a H2O2 + Ce-based solution improved the corrosion resistance ability.

Coatings ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 384
Author(s):  
Dariusz Ulbrich ◽  
Jakub Kowalczyk ◽  
Arkadiusz Stachowiak ◽  
Wojciech Sawczuk ◽  
Jaroslaw Selech

The article presents the influence of the applied method used for removing the varnish coat on the corrosion resistance of the car body sheet. The tests were carried out on samples prepared from factory-painted car body elements with pearlescent, metallized and acrylic varnish. Removal of the varnish coat was performed by sandpaper grinding, glass bead blasting, disc blaze rapid stripping, soda blasting and abrasive blasting with plastic granules. The average thickness of the factory-painted coating depending on the type of lacquer ranged from about 99 to 140 µm. On the other hand, after removing the varnish, the thickness of the protective zinc coating ranged from 2 to 12.7 µm. The highest values of the zinc coating were obtained for samples in which the varnish was removed by the method such as soda blasting and abrasive blasting with plastic granules. For these two methods of surface preparation, the damage to the zinc layer protecting the steel against corrosion is the smallest and the percentage of zinc in the surface layer ranges from 58% to 78%. The final stage of the research was to test the samples after removing the varnish coat in a two-hour exposure to the corrosive environment in a salt spray chamber. Samples with the surface prepared by grinding with sandpaper reached the level of surface rusting Ri 5, while in the case of soda blasting and the use of plastic granules, no corrosion centers were observed on the surface of the car body sheet.


Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 85
Author(s):  
Yuh-Chung Hu ◽  
Senthil Kumaran Selvaraj ◽  
Manivannan Subramanian ◽  
Kathiravan Srinivasan ◽  
Srinivasan Narayanan

A novel phenomenon known as Industry X.0 is becoming extremely popular for digitizing and reinventing business organizations through the adaption of rapid and dynamic technological, innovational, and organizational changes for attaining the profitable revenue. This work investigates the die-casted commercially pure aluminum alloyed with 9% silicon and 3% copper (AlSi9Cu3) that is produced through the gravity die casting process. Further, the degradation of surface coating on die-casted AlSi9Cu3 alloy was explored. The acrylic paint electrodeposition (ED) coat, 2-coat polyester without primer and 3-coat polyester with epoxy primer powder coatings were used in this study. Moreover, the 3.5 wt.% of sodium chloride (3.5 wt.% of NaCl) test solution was used for electrochemical and salt spray test and the tools used to assess electrochemical properties were electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and neutral salt spray test (NSS). The microstructure of AlSi9Cu3 after corrosion exposure was investigated; also, the microstructure of coated and uncoated AlSi9Cu3 samples was analyzed by SEM microscopy after corrosion exposure. Besides, the electrochemical studies were also carried out on the Al alloy die casting. It was found that acrylic paint ED coatings exhibited higher corrosion resistance than 2-coat polyester without primer & 3-coat polyester with epoxy primer powder coatings. Acrylic paint ED coating showed higher corrosion resistance in AC and a lower value in DC and 3-coat polyester with epoxy primer powder coating displayed higher corrosion resistance in DC and a lower value in AC.


2010 ◽  
Vol 105-106 ◽  
pp. 505-508 ◽  
Author(s):  
Zhen Dong Wu ◽  
Zhong Wen Yao ◽  
Fang Zhou Jia ◽  
Zhao Hua Jiang

The coatings containing zirconia were produced on LY12 Aluminium alloy by micro-arc oxidation in K2ZrF6 and NaH2PO2 solution. The composition, structure, hardness, friction and wear resistance and corrosion resistance of the coating were studied by XRD, SEM, EDS, ball-on-disk friction tester and electrochemical analyzer, respectively. The results show that coating was composed of m-ZrO2 and t-ZrO2. There were a large amount of Zr and O and a little Al, P and K in the coating. The thickness of coating prepared for 3h was 168μm and the maximum value of the hardness was up to 16.75GPa. The friction and wear resistance and corrosion resistance were improved, compared with the LY12 aluminium alloy substrate.


2011 ◽  
Vol 121-126 ◽  
pp. 100-104
Author(s):  
Jian Zhong Li ◽  
Yan Wen Tian ◽  
Ying Li ◽  
Yu Cheng Wang

Effect of black plate on growth action and corrosion resistance of Sn-Fe alloy film was investigated by means of metallurgical microscope, scanning electron microscopy (SEM), salt spray corrosion test and electrochemistry methods. The results show that the different modes of annealing and rolling have a remarkably effects on the surface morphology and grain size of Sn-Fe alloys. Crystalline grain of Sn-Fe alloy film for T4-CA or T2.5-BA is relatively continues, homogeneous and denser, but that for DR materials exists obviously surface inhomogeneity sizes and even void space of interweave. Rust spot easily generate on discontinuous alloy films or void space of interweave growth and gradually cover on the surface of Sn-Fe alloy films without corrosion damage. Corrosion resistance of BA materials is better than that of CA materials. Under the same annealing mode, corrosion resistance of DR materials is worse.


Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4037
Author(s):  
Zhenjun Peng ◽  
Hui Xu ◽  
Siqin Liu ◽  
Yuming Qi ◽  
Jun Liang

Phosphate and aluminate electrolytes were used to prepare plasma electrolytic oxidation (PEO) coatings on 6061 aluminum alloy. The surface and cross-section microstructure, element distribution, and phase composition of the PEO coatings were characterized by SEM, EDS, XPS, and XRD. The friction and wear properties were evaluated by pin-on-disk sliding tests under dry conditions. The corrosion resistance of PEO coatings was investigated by electrochemical corrosion and salt spray tests in acidic environments. It was found that the PEO coatings prepared from both phosphate and aluminate electrolytes were mainly composed of α-Al2O3 and γ-Al2O3. The results demonstrate that a bi-layer coating is formed in the phosphate electrolyte, and a single-layered dense alumina coating with a hardness of 1300 HV is realizable in the aluminate electrolyte. The aluminate PEO coating had a lower wear rate than the phosphate PEO coating. However, the phosphate PEO coating showed a better corrosion resistance in acidic environment, which is mainly attributed to the presence of an amorphous P element at the substrate/coating interface.


CORROSION ◽  
10.5006/3866 ◽  
2021 ◽  
Author(s):  
ruilin liu ◽  
Yunqi Liu ◽  
Zheng Lei ◽  
Hui Tang ◽  
Shaoxiong He ◽  
...  

Lightweight steel-aluminium structures have broad application prospects because of their lowering weight characteristics, however, the corrosion of welding-brazing joints in steel-aluminium structures is less concerned or studied. In this paper, the corrosion behaviour of the Laser-MIG hybrid welding-brazing joints of steel-aluminium is investigated through the tests and analysis of salt spray, immersion and electrochemistry. The salt spray and immersion tests show that obvious galvanic corrosion occurs at the welded joints, in which the aluminium side is seriously corroded while the steel side is not corroded. The OCP values of the aluminium alloy and the weld metal are similar (approximately -0.48 V), and the stainless steel has a higher OCP value of -0.33 V. The corrosion resistance of the weld metal is lower than aluminium- as well as steel-base materials. The corrosion resistance of the joints is controlled by the aluminium alloy part of the two metals based on the open-circuit potential and EIS analysis. A possible corrosion process schematic for the physical/chemical properties of a welding-brazing joint immersed in a sodium chloride solution is proposed according to electrochemical impedance spectroscopy.


2000 ◽  
Vol 628 ◽  
Author(s):  
Tammy L. Metrokeand ◽  
Edward T. Knobbe

ABSTRACTSpray-coated, R-Si (OR')3 / TMOS (R = epoxide), thin films are being investigated as room temperature curing corrosion resistant coatings for 2024-T3 aluminum alloy. Solid state 1H-13C CP/MAS NMR indicates that primary aliphatic amines and super acids are effective crosslinkers for epoxide groups in aqueous ormosil systems. Incorporation of a crosslinking agent into the coating was found to reduce the cure time of the deposited film from >7 days to approximately 30 min. Accelerated salt spray and filiform corrosion resistance tests were conducted to determine the effects of crosslinking on the corrosion resistance behavior of ormosil thin films. The choice of curing agent was found to influence film structure and corrosion resistance properties. Amine cured thin films were hard and highly adherent to the aluminum alloy substrates, exhibiting excellent bare and filiform corrosion resistance, in addition to good compatibility with organic polymer paint systems. In contrast, the adhesion and corrosion resistance of super acid cured thin films to aluminum alloy substrates was significantly less, producing films which readily delaminated from the substrate. These observations can be related to the film structure.


2011 ◽  
Vol 418-420 ◽  
pp. 1368-1374
Author(s):  
Ye Ruan ◽  
Xiao Ming Qiu ◽  
Wen Biao Gong

Corrosion behavior and mechanism of 6082-T6 Al-alloy twin wire MIG welded joint under salt spray corrosion in 5 wt.% NaCl solution were investigated via laser scan confocal microscope, scanning electron microscope spectrometer and infrared spectroscope. Pitting was seen on both weld seam and the base metal resulted from Cl-. Uniform corrosion was also seen on the weld seam, grain boundaries had been corroded and approximate circular corrosion channels were observed, while evident pitting corrosion was seen in the base metal. Corrosion resistance of the base metal was better than that of the weld seam. The main corrosion products were composed of Al2O3, Al(OH)3and AlCl3•6H2O. Corrosion had a slight effect on the test sample's tensile strength, and serious results on the plasticity of the joints. In addition, transition from prior corrosion ductile to after corrosion hybrid brittle and ductile morphology was also found on the fracture surface.


2013 ◽  
Vol 750-752 ◽  
pp. 2052-2056 ◽  
Author(s):  
Lu Miao ◽  
Ya Nan Wang ◽  
Yan Hui Li

By vacuum fusion sintering technique made different CeO2 addition Ni-WC composite coatings on 45 steel. Hardness, wear resistance property and corrosion resistance property of the Rare-earth Ni-WC composite coatings were measured and analyzed by Rockwell hardness tester,micro-hardness tester, friction wear testing machine and Salt spray corrosion box. The results showed that:The CeO2 content comes up to 0.75% of the coatings` hardness, wear resistance and corrosion resistance property better than those of other coatings.


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