Zinc Anodizing: The Ultimate FAQ Guide

I know you are probably looking for more information about zinc anodizing.

That’s why this guide explores everything about anodizing zinc.

So, if you want to learn more, read this guide.

What Is Zinc Anodizing?

Zinc anodizing is a finishing method that you will use on metallic materials.

It entails an electrochemical technique that will transform and enhance the outer surface of metal parts.

This enhancement will protect the metal from corrosion and scratches and will offer decorative properties to the metal.

Anodizing

What Are The Benefits Of Zinc Anodizing?

Here are some of the advantages of conducting zinc anodizing:

Enhance Aesthetics

Here, you can apply zinc anodizing either naturally or with a color tint making them stand out and appealing.

Abrasion Resistance

Zinc anodizing forms powerful bonds on the metal surface thereby making them withstand abrasion forces.

Coloring

Zinc anodizing allows you to select a tint or color you can apply during the anodizing procedure.

Easy Maintenance

Here, you can use a mild detergent to clean zinc anodizing surfaces.

Besides, the application and frequency of use will determine how often you will conduct the maintenance practices.

Electrical Insulation

The layer that forms due to zinc anodizing will act as insulators.

Environmentally Responsible

It is possible to recycle the metals that you will use for zinc anodizing.

Graffiti Resistant

Zinc anodizing results in a firm and smooth surface thus reducing recoating or repainting when you use graffiti.

Erosion Resistant

Zinc anodizing is erosion resistant thus making it suitable for industrial application.

Paint or coating can still experience breakdown when you subject them to extreme industrial applications.

Corrosion-resistant

Zinc anodizing will enhance the material making them corrosion resistant, making them useful for industrial applications.

Natural Beauty

Zinc anodizing will provide an appealing clean sheen that is beautiful.

Fade-resistant

Zinc anodizing embeds itself on the metal surface making it resistant to fading.

This is beneficial since you will save costs when it comes to maintenance and recoating.

Prime Base

It is possible to use zinc anodizing as a base when you need to paint the metal for a specific purpose.

Increased Durability

The lifespan of zinc anodizing relies on its thickness.

For this reason, a thicker coat increases the lifespan of the product.

Zinc anodizing will increase the lifespan of the product to up to 30 years.

What Are The Environmental Aspects Of Zinc Anodizing?

Zinc anodizing is water-based and applies no volatile organic compounds.

Besides, it does not use vehicle solvents or resin carriers and uses controlled pigmentation.

Also, zinc anodizing uses no toxic substances or halogenated hydrocarbons.

Neutralization processes will lower zinc anodizing chemicals to suitable dissolved minerals, and the process produces no hazardous by-products.

What Are The Types Of Zinc Anodizing?

Here are some types of zinc anodizing available:

Zinz anodizing

Type I Zinc Anodizing

This type uses chromic acid and is useful when you need a thin coat of zinc with suitable corrosion-resistant properties.

Besides, you will accomplish type I zinc anodizing by chemical conversion technique.

This technique entails the immersion of zinc components in a batch of chromic acid.

Type I anodizing is suitable for applications that will experience high stress, for instance, aerospace industries.

Also, you can use it as a base when you need to apply adhesives or paint.

Besides, you can use type I anodizing as a mask when you plan to perform type III anodizing

Type II Zinc Anodizing

This type will use sulfuric acid and it is a popular choice.

Besides, it is also known as color or decorative anodizing as it forms porous surfaces that will easily accept dyes.

Type II zinc anodizing accelerates the natural oxidation of zinc since you will place the object in a solution of sulfuric acid.

Afterward, you will pass an electric current through the sulfuric acid bath solution.

Besides, you will seal dyed anodizing to stop the dye from bleeding out.

Type II anodizing is common in several industries that conduct general and commercial zinc anodizing.

Also, this type of zinc anodizing relies on ML-A-8625 military specification.

Type III Zinc Anodizing

This is also known as hardcoat anodizing as it will form a dense, thick, and hard coat on the object.

Besides, type III zinc anodizing is similar to type II zinc anodizing.

However, the zinc oxide layer forms at higher voltage levels and cooler temperatures.

Type III zinc anodizing will not undergo any coloring or dyeing.

Besides, you can form some versions of grey to black shades by changing the chemical properties, voltage, or temperature levels of the bath solution.

How Does Batch Anodizing And Continuous Coil Anodizing Compare In Zinc Anodizing?

Batch anodizing entails racking and immersing components in several treatment tanks.

Continuous coil anodizing entails continuously unwinding pre-rolled coils via several tanks that perform anodizing, etching, and cleaning.

Afterward, you will rewind the process for shipment and fabrication.

What Is The Process Of Zinc Anodizing?

Here are the steps you will undertake when performing zinc anodizing:

Step 1

This entails cleaning the zinc components before conducting zinc anodizing.

Besides, this process is vital as it eliminates impurities and debris that may negatively affect the process.

Step 2

Here, you will place the object in an electrolytic bath solution then apply direct current.

This will form a positive electric charge within the zinc and a negative charge within the plates of the electrolyte solution.

The result will be an electrochemical reaction that forms pores on the surface of the zinc object.

This enables the zinc substrate and oxygen ions with a negative charge to form a bond within the solution to form zinc oxide.

Which Type Of Zinc Anodizing Is Suitable For Your Application?

Since there are different types of zinc anodizing, it is important to understand which one is suitable for your application.

Here are the properties of the anodizing types and how they compare:

Type I

This version is for decorative applications and has a coating thickness ranging between 0.08 μm and 0.25 μm.

It has poor weather resistance, low porosity, suitable corrosion-resistant, and is not environmentally friendly.

Besides, it is suitable for making parts requiring corrosion-resistant properties, such as airplane components.

Type II

This version also offers good decorative and corrosion resistance properties.

It forms a thickness value ranging between 2.54 μm and 25 μm with moderate weather resistance.

Besides, it is environmentally friendly and has moderate to high levels of porosity.

Also, you can achieve a clear or dyed appearance with it and is suitable for consumer products.

Type III

This version is suitable for applications that require high corrosion resistance levels.

The thickness value ranges between 12.7 μm and 80 μm, with excellent weather resistance.

It features high porosity traits, is environmentally friendly, and the appearance is either hard black or hard clear.

Die cast zinc parts

What Are Some Of The Applications Of Zinc Anodizing?

Zinc anodizing can find its application in the following areas:

• Automotive industries
• Architecture
• Consumer goods like kitchen equipment
• Telecommunication equipment like radios and photo tools
• Light fixtures
• Duct covers
• Electronic casings
• Military equipment

How Much Does It Cost To Perform Zinc Anodizing?

One reason why zinc anodizing is common is that it is cost-effective.

However, the cost of performing zinc anodizing relies on different factors such as:

• Configuration of the part
• Quantity
• Type of anodizing
• Color

This means anodizing complex components cost more than simple components which need no color finish.

What Color Options Can You Obtain From Zinc Anodizing?

There are various color options you can achieve through the process of zinc anodizing.

This is because the zinc anodizing process allows you to obtain different colors for your application needs.

Some of the color options you can obtain through zinc anodizing include the following:

Zinc Anodizing

• Clear
• Black
• Grey
• Bronze
• Red
• Pink
• Yellow
• Violet
• Blue
• Green
• Gold
• Brown

What Process Will You Undertake When Coloring Zinc Products Using The Zinc Anodizing Process?

The steps entail the following:

Cleaning And Etching

Begin by cleaning the zinc products, then etch them to achieve a shiny and polished surface.

Etching is vital as it eliminates metals that can cause errors during the coloring process.

Building Film Layers

In this step, you will conduct the anodizing process of your choice.

Factors to consider in this process entail:

1. Metal alloy will control the shape and size of the pores.
2. The depth of the pores depends on the concentration of the solution, the temperature of the tank, and voltage.

Adding Color

The methods you will perform when adding color entails the following:

1. Integral coloring

This process will combine coloring and anodizing to color the zinc product in black or bronze shades.

2. Electrolytic coloring

Here, you will immerse zinc components in a bath solution containing metallic salts.

After the solution fills the pore, they offer a strong coating that withstands UV rays.

However, there is a limitation to the colors you can apply.

3. Interference coloring

This process will enlarge the pore structure of the zinc product.

Depositing metals in the pores form light-fast colors such as red, yellow, green, or blue.

The color form is due to the effects of optical interference.

4. Dip coloring

Here, you will place the product in a tank that has a dye, which will fill up the pores.

Afterward, you will boil the surface in deionized water to stop the reaction.

This option offers several colors but is not resistant to UV.

Sealing

Here, you will trap the dye molecules within the pores to prevent the absorption of other unwanted molecules.

The sealing happens in hot water as the crystal formation of hydrates zinc oxide seals the pores.

What Are The Design Tips Worth Considering For Zinc Anodizing?

Some of the tips include:

Watching Out For Tolerances

Zinc anodizing will add to the thickness of the component and this can affect the tolerance.

Select type I or type II zinc anodizing if you need to maintain tight tolerance levels.

Extremes

The workspace corners and edges need to have a minimum radius of 0.5 mm and the part designs should not contain burrs.

These considerations prevent overheating of the work piece that may happen due to increased levels of electric current.

Alternative Finishing Steps

When a zinc part undergoes anodizing, it may have machine marks on its surface.

For this reason, if you need complete uniformity, you can use other finishing processes like bead blasting or polishing.

The anodizing process will achieve a smoother surface than before.

Operate With Batches

When coloring zinc components, it is suitable to anodize them in small quantities.

This will ensure you achieve a high level of uniformity since it is difficult to match the colors between the batches.

What Is Color Matching In Zinc Anodizing?

Color matching is a subtractive and not additive process.

The anodized film will allow light enter to the base, then filter the light as it reflects from the zinc base.

How Durable Is Zinc Anodizing?

Zinc anodizing can last up to 30 years.

Can You Remove Color From A Part Of The Product If It Does Not Match After Zinc Anodizing?

Yes, you can use the phosphoric or chromic solution as they ensure the zinc remains intact.

Alkaline etch can remove the color but will cause some degradation.

Metal anodized structure

What Are Some Testing Methods You Can Employ To Evaluate Zinc Anodizing?

These entails:

Film Thickness Measurement

Here, you will use Eddy Current Method to measure the thickness of the film.

Conductive Measurement

This process is vital as it measures the hardness and strength of the materials you treat using heat.

Evaluation Of Seal Quality Of The Anodic Coating

This will measure the weather resistance of the finish.

How Will You Know If The Zinc Anodizing Process Is A Success?

Some methods to conduct include:

• Checking for the matte finish
• Using simple scratch tests as anodized surfaces are scratch-resistant
• A good zinc anodizing process produces even color dispersal

What Is The Difference Between Zinc Anodizing And Zinc Plating?

Zinc anodizing is an electrochemical process that changes the surfaces of metals without altering their composition.

Zinc plating entails applying a coat of metal of other metallic materials, for instance, plating silver with copper.

What Other Metals Besides Zinc Can You Anodize?

These include:

• Aluminum
• Magnesium
• Titanium
• Stainless steel

For all your anodized zinc parts, we offer high quality and cost effective solution – contact us now for inquiries or questions.