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Aluminum Extrusion Profile Anodizing Treatment Process

Aluminum Extrusion Profile Anodizing Treatment Process

There are two types of Anodizing treatment for Aluminum Extrusion Profile Anodizing Treatment Process: chemical Anodizing and electrochemical Anodizing. The oxide film obtained by chemical Anodizing is thin, soft, not wear-resistant, and has poor corrosion resistance. It is generally not used alone and should be used as a good bottom layer for paint.

Electrochemical Anodizing treatment can obtain a thick and high hardness oxide film, which has better heat resistance, insulation, and corrosion resistance than chemical oxide film. It can also be dyed.

Chemical Anodizing treatment

Acidic chemical Anodizing

formula

Component dosage Component g/L

85% H3PO4 50-60ml/L (NH4) 2HPO4 2-2.5

CrO3 20-25g/L H3BO3 1-1.2

NH4HF2 3~3.5g/L

The temperature is 30-36 ℃; The time is 3-6 minutes.

Description: Colorless to reddish green, 3-4 μ m. The size of the parts remains unchanged after Anodizing, suitable for various aluminum and aluminum alloys.

Formula 2

Component g/L Component g/L

85% H3PO4 45 NaF 3

CrO3 6

The temperature is 20-35 ℃; The time is 10-15 minutes.

It indicates that the film is thin, with good toughness and strong corrosion resistance. After Anodizing, it does not require sealing treatment and is suitable for aluminum and its alloys that require deformation after Anodizing.

Alkaline chemical Anodizing

formula

Component g/L Component g/L

Na2CO3 50 NaOH 2-2.5

Na2CrO3 15

The temperature is 80-100 ℃; The time is 10-20 minutes.

After passivation, the film turns golden yellow with a thickness of 0.5-1, suitable for Anodizing of aluminum, aluminum magnesium, and aluminum manganese alloys, and can be used as a paint substrate.

Filling treatment after chemical Anodizing

Acid Anodizing post-treatment

formula

K2Cr2O730-50g/L; The temperature is between 90 and 95 ℃; The time is 5-10 minutes.

The baking temperature should not exceed 70 ℃ and is suitable for acidic Anodizing with a pH value of 6-6.7.

Passivation treatment after alkaline Anodizing

formula

The temperature is room temperature; The time is 5-15 seconds.

The baking temperature should not exceed 50 ℃.

Sulfuric acid anodizing

Direct current Anodizing

formula

98% H2SO4 180-200g/L; The temperature is 15-26 ℃; The anode current density is 0.8-1.5A/dm2; The voltage is 13-22V; The time is 20-40 minutes; The cathode material is aluminum plate.

Used for protecting aluminum and aluminum alloys from Anodizing.

AC anodizing

formula

98% H2SO4 130-150g/L; The temperature is 13-26 ℃; The Anodizing time is 40-50 minutes; The voltage is 18-28V; The current density is 1.5-2.0A/dm2.

Sulfuric acid anodizing with additives

formula

Component g/L Component g/L

98% H2SO4 150-200 H2C2O4 · 2H2O 5-6

The temperature is 15-25 ℃; The voltage is between 18 and 24V; The current density is 0.8-1A/dm2.

Chromic acid anodizing

The chromate oxide film is relatively thin, only 2-5 μ m. Soft and elastic, it can maintain part accuracy and surface smoothness, but its wear resistance is not as good as sulfuric acid anodizing film.

Formula 1

CrO3 30-40g/L; The temperature is between 32 and 40 ℃; Time is 60 minutes; The anode current density is 0.2-0.6A/dm2; The pH value is 0.65-0.8; The voltage is 0-40V; The area ratio of cathode to anode is 3:1; The cathode material is lead or graphite plate.

Instructions are applicable to polished parts with small dimensional tolerances.

Formula 2

CrO3 50-55g/L; The temperature is between 37 and 41 ℃; Time is 60 minutes; PH value < 0.8; The anode current density is 0.3-0.7A/dm2; The voltage is 0-40V; The cathode material is lead plate or graphite.

The instructions are applicable to general machined parts and sheet metal parts.

Oxalic acid anodizing

The thickness of oxalic acid anodizing film is generally 8-20 μ m. Up to 60 thick μ m. Good elasticity, good electrical insulation, corrosion resistance, and hardness, no less than sulfuric acid anodizing film.

Oxalic acid anodizing consumes a large amount of electricity and requires a cooling device, resulting in higher costs.

Formula 1

H2C2O4 · 2H2O 50-75g/L; The temperature is between 25 and 35 ℃; The current density is 1-2A/dm2; The voltage is 50-60V; The Anodizing time is 30-40 minutes; The anode material is blunt aluminum or lead plate; The power supply is DC.

Explanation: Suitable for protective and decorative anodizing of pure aluminum and aluminum magnesium alloy parts.

Formula 2

H2C2O4 · 2H2O 40-60g/L; The temperature is 15-18 ℃; The time is between 90 and 150 minutes; The current density is 2-2.5A/dm2; The anode material is carbon rod; The voltage is 110-120V; The power supply is DC.

Sulfuric acid hard anodizing

The thickness of the hard anodized film can reach 250-300 μ m. The hardness (HV) can reach 2452-4903MPa on aluminum alloys and 11768-14710MPa on pure aluminum; The resistance coefficient is relatively high, and the breakdown voltage can reach 2000V. Mainly used for Anodizing of wear-resistant, heat-resistant, and insulated aluminum alloy parts.

Sulfuric acid hard Anodizing solution has simple composition, good stability, convenient operation, low cost, and can be used for various aluminum materials.

Formula 1

98% H2SO4 200-300g/L; The temperature is -8-10 ℃; The time is 120-150 minutes; The current density is 0.5-5A/dm2; The voltage is 40-90V.

The instructions apply to deformed aluminum alloys.

Formula 2

98% H2SO4 130-180g/L; The temperature is 10-15 ℃; The time is 60-180 minutes; The current density is 2A/dm2; The voltage is 5-100V.

Formula 3

98% H2SO4 270g/L; The temperature is -3~3 ℃; The time is 120-150 minutes; The current density is 2-2.5A/dm2; The voltage is 40-60V; The cathode material is lead plate.

Porcelain anodizing

Porcelain anodizing is the process of obtaining a uniform, smooth, glossy, and opaque oxide film on polished aluminum alloys and hard aluminum surfaces, similar in appearance to enamel and enamel. This type of ceramic film has high hardness, wear resistance, thermal insulation, electrical insulation, and corrosion resistance. Suitable for protecting the surface of high-precision parts on various instruments and electronic instruments, or decorating the surface of daily necessities and food utensils.

Formula 1

Component g/L Component g/L

K2TiO2 (C2O4) 2 35-45 H3C6H5O7 · H2O 1-1.5

H3BO3 8-10 H2C2O4 · 2H2O 2-5

The temperature is 24-28 ℃; The time is 30-40 minutes; The current density starts at 2-3A/dm2 and ends at 0.6-1.2A/dm2; The voltage is between 90 and 110V; The cathode material is silicon carbon rod and pure aluminum plate.

Instructions are applicable to high-precision wear-resistant parts.

Formula 2

Component g/L Component g/L

CrO3 30-40 H3BO3 1-3

The temperature is 40-50 ℃; The time is 40-60 minutes; Current density 2-4A/dm2; The voltage is 40-50V; The cathode material is lead plate or pure aluminum plate.

Instructions apply to anodizing of protective and decorative aluminum parts.

Other anodizing

High efficiency anodizing

formula

Component g/L Component g/L

98% H2SO4 150-180 glycerol 10-12

1631-Br 0.2-0.3 Lactic acid 10-12

The temperature is 18-22 ℃; Time is 10 minutes; Current density 0.8-1A/dm2; The voltage is 10-12V; The mixing method is compressed air.

Wide temperature range anodizing

formula

Component g/L Component g/L

98% H2SO4 140-160 H2C4H4O6 20-60

The temperature is 10-50 ℃; The time is 30-40 minutes; The current density is 1-2A/dm2.

It can be continuously produced without refrigeration equipment and has a long solution life.

Phosphoric acid anodizing

formula

Component g/L Component g/L

85% H3PO4 200 K12 0.1

H2C2O4 · 2H2O 5

The temperature is 20-25 ℃; The time is 18-20 minutes; Current density 2A/dm2. The voltage is 25V.

Sealing treatment of anodic oxide film

Chelate blocking

formula

K2Cr2O7 40-70g/L; The temperature is 80-95 ℃; The time is 10-20 minutes.

Hydrolyzed salt blocking

Formula 1

Component g/L Component g/L

Ni (Ac) 2 4-5 98% H2SO4 0.4-2

The pH value is between 5.5 and 6; The temperature is between 93 and 100 ℃; The time is 20 minutes.

Formula 2

Component g/L Component g/L

NiSO4 · 7H2O 3-5 H3BO3 1-3

NaAc · 3H2O 3-5

The pH value is 5-6; The temperature is 70-90 ℃; The time is 10-15 minutes.