Preparation and Properties of Cerium Conversion Coatings on the Surface of Aluminum Alloy LY12

2012 ◽  
Vol 182-183 ◽  
pp. 241-244
Author(s):  
Cheng Bao Xia ◽  
Wen Jun Ge ◽  
Hou Chuan Yang

In order to improve the repairing quality of aircraft envelope of the aluminum alloy LY12, the cerium conversion coating technology was studied by using the surface modification technique. Principle experiment was on the basis of aviation repair technological requirement, refers to the related technique, through examination of corrosion resistance and wear resistance performance of cerium conversion coating, the principal composition of the formula for making cerium conversion coating:Ce(NO3)3 + KMnO4+ Ce-1 (chemical additive), In order to determine each composition of the formula and the technology parameters scientifically, L9(34) orthogonal testing method was adopted, and the formula of surface modification solution was optimized, the technological conditions for making cerium conversion coating on the surface of aircraft envelope were determined. Results of corrosion resistance and wear resistance of the cerium conversion coating on the surface of the aluminum alloy LY12 aircraft envelope obtained by the new technology showed: 1. On the given test conditions, the best content of each chemical composition in the formula of modification solution for making cerium conversion coating on the surface were: l.Ce(NO3)3:14g/L,KMnO4:1g/L,addictive Ce-1:0.3g/L;Main technology parameters were :pH=1.5~2.7;temperature:20°C;time:15~25 min.;2. Under the same test condition, the corrosion resistance of surface of the cerium conversion coating obtained in test modification solution was better than Alodine 1001 obtained from Bombardier Corporation of Canada, and can meet the repairing demands of Aircraft Envelope.

Coatings ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 397 ◽  
Author(s):  
Hehong Zhang ◽  
Xiaofeng Zhang ◽  
Xuhui Zhao ◽  
Yuming Tang ◽  
Yu Zuo

A chemical conversion coating on 5052 aluminum alloy was prepared by using K2ZrF6 and K2TiF6 as the main salts, KMnO4 as the oxidant and NaF as the accelerant. The surface morphology, structure and composition were analyzed by SEM, EDS, FT–IR and XPS. The corrosion resistance of the conversion coating was studied by salt water immersion and polarization curve analysis. The influence of fluorosilane (FAS-17) surface modification on its antifouling property was also discussed. The results showed that the prepared conversion coating mainly consisted of AlF3·3H2O, Al2O3, MnO2 and TiO2, and exhibited good corrosion resistance. Its corrosion potential in 3.5 wt % NaCl solution was positively shifted about 590 mV and the corrosion current density was dropped from 1.10 to 0.48 μA cm−2. By sealing treatment in NiF2 solution, its corrosion resistance was further improved yielding a corrosion current density drop of 0.04 μA cm−2. By fluorosilane (FAS-17) surface modification, the conversion coating became hydrophobic due to low-surface-energy groups such as CF2 and CF3, and the contact angle reached 136.8°. Moreover, by FAS-17 modification, the corrosion resistance was enhanced significantly and its corrosion rate decreased by about 25 times.


2018 ◽  
Vol 207 ◽  
pp. 03023
Author(s):  
Masataka Ijiri ◽  
Toshihiko Yoshimura

In this study, to further improve current multifunction cavitation (MFC) techniques, the surface modification of Cr‒Mo steel was further investigated using 1200 W ultrasonic power. In MFC using 1200 W ultrasonic power, the corrosion resistance, and compressive residual stress of the specimens were improved when the processing time was 10 min; however, decarburization occurred at longer processing times, causing these characteristics to worsen. The decarburization that occurs at high ultrasonic outputs may be caused by an increase in the water temperature, and of the heating of the specimen surface.


Coatings ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 578 ◽  
Author(s):  
Guodong Zhu ◽  
Shouren Wang ◽  
Wei Cheng ◽  
Gaoqi Wang ◽  
Wentao Liu ◽  
...  

The surface of the aluminum alloy is prone to oxidation, which in turn affects the quality of the weld. The 5A12 aluminum alloy was cleaned by acousto-optic Q-switched diode-pumped Nd:YAG laser and the effects of different laser powers and different cleaning speeds on the surface roughness, microstructure, element content, microhardness, residual stress and corrosion resistance of aluminum alloy were investigated. The results show that when the power is 98W and the cleaning speed is 4.1 mm/s, the effect of Nd: YAG laser on the removal of oxide film on 5A12 aluminum alloy surface is the most effective. After laser cleaning, the smoothness and strength of aluminum alloy surface can be effectively improved. However, as a major element in 5A12 aluminum alloy, the content of magnesium decreased. At the same time, the residual tensile stress was generated on the surface of the aluminum alloy after cleaning, and the corrosion resistance slightly decreased.


2018 ◽  
Vol 6 (43) ◽  
pp. 6936-6949 ◽  
Author(s):  
Hao Zhang ◽  
Lingxia Xie ◽  
Xiaolong Shen ◽  
Tengda Shang ◽  
Rifang Luo ◽  
...  

A catechol/polyethyleneimine conversion coating on a MgZnMn alloy possessed good corrosion resistance. Heparin was further grafted on it and this showed the potential for surface modification of magnesium-based vascular implants.


Coatings ◽  
2020 ◽  
Vol 10 (3) ◽  
pp. 249
Author(s):  
Wanying Liu ◽  
Yi Pu ◽  
Hongcheng Liao ◽  
Yuanhua Lin ◽  
Wanying He

The effect of added graphene concentration on the microstructure, phase composition, corrosion- and wear- resistance of plasma electrolyte oxidation (PEO) coatings formed on D16T aluminum alloy in silicate electrolyte with different concentrations of graphene were investigated. The results show that the morphologies of the coatings with graphene were obviously different ascribed to the mode of graphene incorporated into the coating. The coatings consisted of mainly α-Al2O3, γ-Al2O3, and Al, which were divided into an outer porous layer and a dense inner layer. The thickness of the coatings increased non-linearly with graphene concentration. The corrosion resistance of the coatings with graphene was significantly improved. The wear resistance of the coatings was also greatly improved apart from the coating with 3 g/L graphene. The coating produced in the electrolyte with 2 g/L graphene exhibited the optimal comprehensive properties because graphene successfully incorporated into the coating via the pores and spread on the surface of the coating.


2012 ◽  
Vol 500 ◽  
pp. 117-122
Author(s):  
Xiu Li Fu ◽  
Xiao Qin Wang ◽  
Yong Zhi Pan ◽  
Yang Qiao

The wear-resistance performance of machined surface is an important factor in the evaluation of surface quality and precision in aerospace manufacturing industry. By using high-speed Ring-Block friction and wear machine (MRH-3), the influence of cutting parameters in milling aluminum alloy 7050-T7451 on wear-resistance of machined surface including friction coefficient and wear quantity are experimentally investigated. The wear-resistance is particularly sensitive to cutting speed and feed rate. The friction coefficient has marked drop trends as cutting speed increases. The influence of cutting speed on wear quantity is more complicated and the tendency of wear quantity was ascend in first and descend at last (v>900/min). The results show that the influence of cutting parameters on wear-resistance was also positively correlated with surface roughness and work-hardening of machined surface. The high work-hardening and surface quality had the promoting effecting on wear-resistance. The experiment and analysis results show that the machined surface by high speed cutting and lower feed rate has more superior in surface quality and wear-resistance performance comparing with conventional cutting speed.


2014 ◽  
Vol 881-883 ◽  
pp. 1385-1390
Author(s):  
Xian Fang Yang ◽  
Tian Quan Liang ◽  
Wei Wei ◽  
Dong Hui Deng ◽  
Guang Qiao Xu ◽  
...  

Preparation and the characteristics of environment-friendly Ce-Ti-Mn conversion coating on aluminum alloy 6061 were investigated by XRD, FESEM, EDS, TEM and AFM in this paper. It is indicated that coating characteristics such as the surface morphologies, microstructure and corrosion resistance, are greatly influenced by the formation technology at room temperature. The constituents and their concentration, and pH value of the conversion solution have an important role on the feature of Ce-Ti-Mn conversion film, which will significantly influence on the continuity, compactness and the crystalline structure of particles of the film. The concentrations of the main salt K2TiF6and oxidizer KMnO4have significant effect on the characteristics of the conversion coating. The Ce-Ti-Mn film grows in a lamellar way, composing of oxide and/ or hydroxide phases of Ce, Ti and Mn, some of which are amorphous. The formation mechanism of the Ce-Ti-Mn conversion coating is discussed in detail.


Author(s):  
Xu zheng Qian ◽  
Wen Zhan ◽  
Jing jing Pan ◽  
Yi ting Liu ◽  
Feng Huang ◽  
...  

2019 ◽  
Vol 71 (3) ◽  
pp. 419-429 ◽  
Author(s):  
Wen Zhan ◽  
Xuzheng Qian ◽  
Boyi Gui ◽  
Lian Liu ◽  
Xiaohui Liu ◽  
...  

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