Optimization of Environmentally Friendly Anodic Oxide Film for Magnesium Alloys

Hara, Masaaki; Matsuda, Kenji; Yamauchi, Wataru; Sakaguchi, Masaaki; Yoshikata, Toshiyuki; Takigawa, Yorinobu; Higashi, Kenji

doi:10.2320/matertrans.47.1013

Cited by 11 publications

(4 citation statements)

References 10 publications

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“…[20][21][22][23][24] Figure 8 shows the thickness of the oxide film on the fresh surface of magnesium alloy and the dependency of the corrosion rate on the concentration of aluminum. 26,31) The film thickness decreases as the concentration of aluminum in the magnesium alloy increases, and the corrosion resistance is improved.…”

Section: Corrosion Resistance and Properties Of The Filmmentioning

confidence: 99%

Surface Treatment to Provide a Metallic Luster to AZ31 Magnesium Alloy

Ohara¹,

Higashi

2011

Mater. Trans.

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To form a metallic luster on AZ31 magnesium alloy, it is necessary to optimize the surface morphology since the surface roughness affects the specular reflection of visible light, and the surface structure such as the film thickness and properties must be optimized so that light is not absorbed. We conducted experiments to analyze the relationship between surface roughness and specular reflection, and determined the range required to produce metallic luster. The ratio of the root mean square roughness ' to the wavelength of incident light ! was 0-0.067, and the ratio of the specular reflectivity R of the specimens to the specular reflectivity of a smooth surface R 0 was 0.54-1.0. The thickness of film to form a metallic luster was theoretically analyzed and found to be about 100 nm or less. The authors developed an optimum acid aqueous solution for treating the surface to form a metallic luster on the surface of AZ31 magnesium alloy. This treatment satisfied the range required to form a metallic luster identified theoretically, and formed a film with a stable structure that maintained its metallic luster. The treatment maintained the geometrical patterns such as the hair-line and blast finishing of several hundred nm or more. A sufficiently high-quality surface for exterior parts was obtained by improving the process, and the process was industrialized.

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Section: Corrosion Resistance and Properties Of The Filmmentioning

confidence: 99%

Surface Treatment to Provide a Metallic Luster to AZ31 Magnesium Alloy

Ohara¹,

Higashi

2011

Mater. Trans.

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“…However, traditional production method of chassis produces a problem with surface treatment. The chassis surface is characterized by its luster, but if conventional surface treatment using chemicals and anodization [2][3][4][5][6] is applied to magnesium alloys, the surface luster is usually lost. Another problem is surface scorches and flaws that occur during press forming [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Development of Surface Treatment in Industrial Scale for Components with Metallic Luster on AZ31 Sheets

Ohara¹,

Takigawa

Higashi

2009

MSF

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We have developed a new surface treatment, Mgbright, which produces a luster on AZ31 magnesium alloy surfaces. The treatment consists of a chemical process and a coating process, and the primary characteristics are that of developing a luster on AZ31 magnesium alloy and imparting a high resistance to corrosion. When Mgbright was applied, the value of surface roughness, Ra, required for developing luster was 1.5 µm. As the target Ra value of press-formed articles was set to less than 1.5 µm, mass-production press-forming was tested by means of the 100,000 times square-cup drawing method, and the target was achieved. We applied the Mgbright treatment techniques and the square-cup drawing test, and produced a laptop computer chassis.

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“…Therefore, we consider the optimum treatment method to be the composite treatment of anodizing for over 10 mm of economical passive film, in place of conventional thin film chemical conversion as a substrate treatment, and on it, apply electrodeposition coating which is economical and has good covering power. [7][8][9][10] In our previous paper, 11) as an environmental measure, we reported an environmentally friendly and excellent corrosion resistant SAF which did not contain any hazardous substances, unlike DAF and CCF containing hexavalent chromium as well as fluorine and phosphorus compounds.…”

Section: Introductionmentioning

confidence: 99%

Environmentally Friendly Composite Film of Anodizing and Electrodeposition Coating Having a High Corrosion Resistance on Magnesium Alloy AZ91D

et al. 2007

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In this study, we compared and examined the corrosion resistance of the magnesium alloy with the composite film of 2 kinds of coating on 3 kinds of surface treated film as the substrate treatment. 3 kinds of surface treated film stands for conventional DOW17 anodized film (DAF), chemical conversion treatment JISA3-type MX3 film (CCF), which contain hexavalent chromium, fluorine and phosphorus compounds, and environmentally friendly silicate anodized film (SAF) containing no hazardous substances and 2 kinds of coating stands for organic coating and electrodeposion coating. As a result of the analysis, we could observe that it was extremely effective for magnesium alloy AZ91D to apply the composite film of environmentally friendly SAF with cationic electrodeposition coatings to obtain superior corrosion resistance to that of the composite film of conventional DAF or CCF with organic spray coating. At the same time we could take an action for the environment countermeasure by using the environmentally friendly SAF with the water base cationic electrodeposition coatings as a countermeasure for VOC (Volatile Organic Compound) regulations.

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Optimization of Environmentally Friendly Anodic Oxide Film for Magnesium Alloys

Cited by 11 publications

References 10 publications

Surface Treatment to Provide a Metallic Luster to AZ31 Magnesium Alloy

Surface Treatment to Provide a Metallic Luster to AZ31 Magnesium Alloy

Development of Surface Treatment in Industrial Scale for Components with Metallic Luster on AZ31 Sheets

Environmentally Friendly Composite Film of Anodizing and Electrodeposition Coating Having a High Corrosion Resistance on Magnesium Alloy AZ91D

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