A Zr- and Cr(III)-containing conversion coating on Al alloy 2024-T3 and its self-repairing behavior

2016 ◽  
Vol 68 (3) ◽  
pp. 338-346 ◽  
Author(s):  
C. Cai ◽  
X.-Q. Liu ◽  
X. Tan ◽  
G.-D. Li ◽  
H. Wang ◽  
...  
Keyword(s):  
2007 ◽  
Vol 515 (23) ◽  
pp. 8386-8392 ◽  
Author(s):  
S.A. Kulinich ◽  
A.S. Akhtar ◽  
P.C. Wong ◽  
K.C. Wong ◽  
K.A.R. Mitchell
Keyword(s):  

2014 ◽  
Vol 622-623 ◽  
pp. 37-44
Author(s):  
Varunee Premanond ◽  
Pongpan Niyomrit

During the process of cold forming of aluminum, the high pressure which is introduced on the die can result in high adhesion between the aluminum and the die surface. Therefore, it is necessary for the aluminum billet to be coated with a lubricant prior to forming, to reduce adhesion and to ease the flow of material in the die. There are several popular types of lubricant systems used in cold forging of aluminum. For severe deformation, conversion coating in conjunction with soap lubricant are commonly used. The conversion coatings include soap phosphates (PO4-soap), as well as soap aluminum fluoride (AlF-soap). Therefore, this work studied the performance of the AlF-soap system and compared it to the conventional PO4-soap system as tested on AA6063 aluminum. Ring compression tests and ball on disc tests were conducted to explore friction conditions and the thinning of the lubricant under several forming conditions. It was found that the quantity of metal soap layer of AlF-soap used affected the friction coefficient and the lubricant thinning under forming operation. The suitable coating weight of metal soap layer of AlF-soap for this experiment was found to be 2 g/m2. The friction coefficient of the PO4-soap system was 16.26% lower than the AlF-soap system. However, the amount of thinning of the AlF-soap film after ring compression tests was lower than that of PO4-soap film.


2017 ◽  
Vol 394 ◽  
pp. 275-281 ◽  
Author(s):  
Caixia Zhang ◽  
Xiaohu Luo ◽  
Xinyu Pan ◽  
Liying Liao ◽  
Xiaosong Wu ◽  
...  

2008 ◽  
Vol 202 (14) ◽  
pp. 3396-3402 ◽  
Author(s):  
C.M. Rangel ◽  
T.I. Paiva ◽  
P.P da Luz

2012 ◽  
Vol 460 ◽  
pp. 86-89
Author(s):  
Qi Zhou ◽  
Hong Yan Liu ◽  
Xiu Lian Cheng ◽  
Guang Sen Zhang

Chromium-free conversion coatings were generated to replace chromate chemical process by electrolysis treatment LY12 aluminum alloy in zirconate solution. Film thickness, dropping test, the adhesion between aluminum and paint film were tested for single-factor experiments and orthogonal to seek better electrolysis process. The paint adhesion is the first grade for electrochemical conversion solution containing complexing agents, or it is the second grade without complexing agents. When DNS complexing agent is 2 ~ 5g/L, film corrosion resistance rises with the increasing content of complexing agent. If voltage is too low, corrosion resistance of conversion coating is poor; voltage is too high, the films form powders. Better formulations for zirconate conversion coating are: 5g/L DNS complexing agent, 10V voltage, treatment temperature is 40°C. Electrochemical conversion coating is thinner than chemical conversion, but the corrosion resistance is better because the electrochemical conversion coatings are smoother and compacter than the chemical conversion coating. The paint films on electrochemical conversion coating are smoother than the chemical one. Two kinds of conversion coatings have very good adhesion with paint film up to the first level. Electrochemical conversion coatings thickness is 2.5 μm, bubble time of NaOH-glycerine solution on them is up to 92s.


2018 ◽  
Vol 51 (4) ◽  
pp. 465-474 ◽  
Author(s):  
Zi-Wen Sun ◽  
Gang Kong ◽  
Chun-Shan Che ◽  
Yan-Qi Wang ◽  
Xin-Rui Miao

2020 ◽  
pp. 1-9
Author(s):  
Ziwen Sun ◽  
Gang Kong ◽  
Shuanghong Zhang ◽  
Yanqi Wang ◽  
Chunshan Che

2009 ◽  
Vol 19 (4) ◽  
pp. 892-897 ◽  
Author(s):  
Masazumi OKIDO ◽  
Ryoichi ICHINO ◽  
Seong-Jong KIM ◽  
Seok-Ki JANG

2008 ◽  
Vol 373-374 ◽  
pp. 224-227 ◽  
Author(s):  
Dong Chu Chen ◽  
Gui Xiang Wu ◽  
Wen Fang Li ◽  
Wen Hui Gong ◽  
Yi Qing Liang

In order to develop an environment-benignly chemical conversion process to substitute the toxic hexavalent chromium treatment on Al alloy surface, a new surface treatment technology based on rare-earth element, which is to form chemical conversion coating on 6063 Al alloy was presented. In this process, Ce(NO3)3 was adopted in the chrome-free preparing solution, and KMnO4 was used as oxidant to accelerate the coating formation on 6063 Al alloy. Furthermore, an L16(43) orthogonal experiment was carried out to examine the effect of Ce(NO3)3, KMnO4 and solution temperature on the coating growth on 6063 Al alloy. Accelerants of SrCl2 and NH4VO3 were added to the preparing solution to improve the coating performance. XRD, SEM and EDS were used to analyse the coating surface structure, morphology and composition. It was found that a good anti-corrosion coating which is mainly composed of the elements of Al, Ce, O, Mn, Mg could be formed in the optimal preparing solution of 5g/L Ce(NO3)3 , 4g/L KMnO4, 1.4g/L SrCl2 at the temperature of 20°C.


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