Growth behaviour of cerium-based conversion coating on Zn-5%Al alloy

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

Growth behaviour of cerium-based conversion coating on HF pre-treated Zn–5%Al alloy

2020 ◽  
pp. 1-9
Author(s):  
Ziwen Sun ◽  
Gang Kong ◽  
Shuanghong Zhang ◽  
Yanqi Wang ◽  
Chunshan Che
Keyword(s):  
Conversion Coating ◽  
Al Alloy ◽  
Growth Behaviour

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):  
Conversion Coating ◽  
Al Alloy

Growth of permanganate conversion coating on 2024-Al alloy

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):  
Conversion Coating ◽  
Al Alloy

Solidification Behaviour of 357 Al-Alloy under Intensive Forced Convection

2006 ◽  
Vol 519-521 ◽  
pp. 1747-1752 ◽  
Author(s):  
Michael Hitchcock ◽  
Zhong Yun Fan
Keyword(s):  
Forced Convection ◽  
Ostwald Ripening ◽  
Particle Growth ◽  
Primary Phase ◽  
Al Alloy ◽  
Growth Behaviour ◽  
Entire Volume ◽  
Solidification Behaviour ◽  
Primary Particles ◽  
Fast Growth Rate

Solidification behaviour of 357 Al-alloy under intensive forced convection in the rheo-die-casting (RDC) process, was investigated experimentally to understand the effects of the intensity of forced convection and shearing time on the nucleation and growth behaviour. It was found that under intensive forced convection, heterogeneous nucleation occurred continuously throughout the entire volume of the solidifying melt. All the nuclei could survive due to the uniform temperature and composition fields created by the forced convection. This has been named as ‘effective and continuous nucleation’. It is also found that the nuclei grow spherically with an extremely fast growth rate. This makes the primary solidification essentially a slow coarsening process, in which Ostwald ripening takes place by dissolution of the smaller particles. In addition, it was found that intensive forced convection suppresses partially the formation of the primary phase, promote nucleation of the primary particles, and hinders the particle growth.

Characteristics of Fluoride Based Conversion Coating Film on Al-Alloy for Metal Forming Applications

2014 ◽  
Vol 622-623 ◽  
pp. 37-44
Author(s):  
Varunee Premanond ◽  
Pongpan Niyomrit
Keyword(s):  
Friction Coefficient ◽  
Soap Film ◽  
Conversion Coating ◽  
Cold Forging ◽  
Al Alloy ◽  
Coating Film ◽  
Compression Tests ◽  
Metal Soap ◽  
Cold Forming ◽  
Ring Compression

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.

OS2610 Effect of Humidity on Growth Behaviour of a Fatigue Crack of Age-hardened Al Alloy

2011 ◽  
Vol 2011 (0) ◽  
pp. _OS2610-1_-_OS2610-3_
Author(s):  
Kohji KARIYA ◽  
Norio KAWAGOISHI ◽  
Masahiro GOTO
Keyword(s):  
Fatigue Crack ◽  
Al Alloy ◽  
Growth Behaviour

Self-healing Li-Al layered double hydroxide conversion coating modified with aspartic acid for 6N01 Al alloy

2017 ◽  
Vol 394 ◽  
pp. 275-281 ◽  
Author(s):  
Caixia Zhang ◽  
Xiaohu Luo ◽  
Xinyu Pan ◽  
Liying Liao ◽  
Xiaosong Wu ◽  
...  
Keyword(s):  
Aspartic Acid ◽  
Layered Double Hydroxide ◽  
Conversion Coating ◽  
Al Alloy ◽  
Self Healing ◽  
Double Hydroxide

Conversion coating growth on 2024-T3 Al alloy. The effect of pre-treatments

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

Zirconate Conversion Coatings on Al Alloy by Electrochemical Method

2012 ◽  
Vol 460 ◽  
pp. 86-89
Author(s):  
Qi Zhou ◽  
Hong Yan Liu ◽  
Xiu Lian Cheng ◽  
Guang Sen Zhang
Keyword(s):  
Corrosion Resistance ◽  
Paint Film ◽  
Chemical Conversion ◽  
First Grade ◽  
Conversion Coating ◽  
Complexing Agents ◽  
Complexing Agent ◽  
Al Alloy ◽  
Conversion Coatings ◽  
Electrochemical Conversion

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.

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