Anodized Magnesium: The Ultimate FAQ Guide

Anodized magnesium refers to a type of magnesium part with a stable, thick oxide layer formed on the surface.

Ideally, this oxide layer is attained through an electrolytic process, which transforms the outer surface into durable, non-corrosive, and scratch-resistant.

This article discusses different aspects of anodized magnesium and touches on critical elements like advantages, design tips, features, applications, etc.

What Advantages Do Anodized Magnesium Offer?

Ordinarily, anodized magnesium provides a wide range of benefits when used in different applications.

Some of these advantages include the following;

Anodized magnesium part

Enhanced Material Properties

Anodized magnesium exhibits some of the best properties when used in a wide range of projects across different sectors.

For instance, it is immensely durable, corrosion-resistant, and scratch-resistant, making it ideal for numerous projects.

Improved Aesthetics

Oxide layer on the surface material produces enhance the overall appearance of the part.

You can also add color variations on anodized magnesium to give a better overall appealing appearance.

Of course, this is fundamental since it increases the value of the part of a project where it is used.

Cost-effective

Since anodization process improves the overall material property, you can be certain of cutting costs.

For instance, durability, scratch resistance, and corrosion resistance enhance the service lifespan on the part.

Hence, you will save on costs you’d otherwise spend on repairing or replacing the respective parts.

Moreover, magnesium is one of the leading materials available globally, making it easy to find at affordable rates.

Eco-friendly

Anodized magnesium is safe for the environment since it hardly emits any toxic substances.

Still, this material is 100% recyclable making it more eco-friendly since you will hardly find it in landfills.

Increased Tensile Strength

Typical anodized magnesium exhibits higher tensile strength, which makes it suitable for applications where constant vibration is a concern.

Ordinarily, it will absorb all the vibration and still guarantee efficiency in the specific application.

Which Type Of Anodizing Should You Consider For Magnesium?

The ideal anodizing type for magnesium usually varies depending on the specific application of the part.

In essence, types of anodizing processes for magnesium vary are designed for particular circumstances.

There are three major anodizing types you can use on magnesium, and they include the following;

Type I – Chromic Acid Anodizing

It uses chromic acid to form a thin layer on the surface of magnesium material.

You may consider it for applications where corrosion resistance is a significant concern, such as making aircraft parts.

Type II – Sulfuric Acid Anodizing

Type II anodized magnesium are bathed in sulfuric acid to produce a slightly thicker surface coating on the part.

Mostly, magnesium parts anodized through this process often have a thickness of 0.0002 to 0.001 inches.

They are primarily suitable for making dyeing parts.

Type III – Hard Coat Anodizing

This type of anodizing method also uses sulfuric acid but yields a thicker anodized layer than type II.

It is an ideal choice to consider for applications where abrasion resistance is a major concern.

Also, you may use it for applications that need wear resistance since it will outperform other anodizing types due to its thicker layer.

Moreover, it may reduce fatigue life, but it may not suit parts with immense tight tolerance.

What Are The Available Color Options For Anodized Magnesium?

Anodized magnesium are available in different color options depending on the specific anodization type used to coat it.

Ideally, the standard color of most anodized magnesium parts is silvery-white.

But you can find it in many other color variants, which include the following;

• Brown
• Violet
• Gold
• Yellow
• Black
• Red

What Are The Main Design Tips For Anodizing Magnesium?

Anodizing magnesium parts is usually a straightforward process.

However, to attain the best results, it is imperative to incorporate a few tips to make the process efficient such as the following;

Check Out The Tolerances

Always have it in mind that anodization adds some layer to the surface of the magnesium.

It is important since the process can easily affect part tolerance, albeit slightly.

If your applications must use tight tolerances, it is recommended to go for Type I or Type II anodizing types.

Besides, you may want to consider the additional layer during design stage.

Always Work With Batches

If you are painting magnesium parts, it is recommended to anodize them in relatively small batches.

It is important since it guarantees a significant color uniformity degree since it can be challenging to precisely match a color from different batches.

The suitable scenario for attaining color uniformity is thus by anodizing small batches of small parts at a time.

Consider Using Other Surface Finishing Techniques

Since anodizing is an electrochemical process, it hardly has same effect as polishing or bead blasting.

If you use magnesium part straight from anodizing, it will have a few scratches or machine marks on the surface.

Hence, for a completely even surface finish, it would be ideal for polishing, bead blast, or using any suitable mechanical finish.

Corners And Edges

It is advisable that edges and corners of magnesium workpiece have a radius of at least 0.5mm.

Moreover, the part designs should never integrate any burrs.

Essentially, these considerations are vital since they prevent workpieces from overheating or burning due to high electric current concentration.

How Does Anodizing Magnesium Work?

Anodizing magnesium

Magnesium is anodized by using an alkali-rich aqueous bath.

What happens is that the base material is cleaned thoroughly to remove any impurities before bathing it in the aqueous bath.

Then placing the material into the aqueous bath follows.

Technically, it entails applying a direct current, which is reversed incompletely in polarity.

This process creates a positive electrical charge on the magnesium part and a negative electric charge in alkali solution.

Alternatively, it can be turned off to allow formation of magnesium compounds proven to portray excellent corrosion resistance when tested with salt spray.

Electrochemical reaction between the magnesium component and alkali solutions forms a pore on the metal surface.

While at it, the magnesium’s substrate bonds with negatively charged ions in the aqueous bath.

It forms anodic oxide film on magnesium surface, and it becomes anodized.

What Is The Cost Of Anodized Magnesium?

The cost of anodized magnesium usually varies based on a wide range of factors.

For instance, the specific type of anodizing method you are using to attain the final product determines the cost.

Type I and Type II anodizing methods are often relatively cheaper than Type III anodizing technique.

Hence, Type I and Type II anodized magnesium parts are likely to be more affordable than Type III anodized components.

Another cost determinant factor of this material is the exact magnesium alloy you use.

Magnesium is generally available in different alloys, all with varying properties, albeit marginally.

Also, the actual dimensions of anodized magnesium part you are buying will determine the definite cost.

Anodized magnesium with a thicker oxide layer is more expensive than one with a relatively thin film.

Notably, the manufacturer you are buying anodized magnesium from also determines the specific cost depending on various factors.

In a nutshell, there is no definite cost of this part, and it often varies based on many factors, as mentioned above.

What Types Of Magnesium Alloy Can You Anodize?

Typically, magnesium alloy is quite abundant and mostly available in different alloys.

The common ones you can easily anodize include the following;

Magnesium alloy

• Wrought magnesium – It is a magnesium alloy that has undergone numerous mechanical workings like forging, extrusion, and rolling to obtain its shape.
• Cast magnesium – This magnesium is created by pouring melted metal into a mold to solidify into desired shape.
• WE43 – It is a magnesium alloy with a tensile strength of 250 Mpa and is usually anodized to suit different applications.
• AJ62A – This die castable magnesium alloy is usually anodized using different anodizing techniques depending on the specific application.
• AZ31B – It is a wrought magnesium alloy with reasonable tensile strength and immense corrosion resistance.

Is Anodized Magnesium Toxic?

No.

Of course, anodized magnesium consists of numerous compounds, including the different alloying substances.

Besides, this material in its raw form can be relatively explosive and somewhat toxic.

However, the anodizing process provides an additional layer on the surface of base material that inhibits any toxicity.

Hence, you can use anodized magnesium in different applications, but it will never emit harmful substances.

How Does Anodized Magnesium Compare With Anodized Aluminum?

Notably, anodized magnesium and anodized aluminum are the dominant materials in several applications.

They exhibit different chemical and structural substances that set them apart.

Here is how these two materials compare;

• Weight

Anodized aluminum is structurally lightweight and presents high malleability and ductility, thus suitable for precision machining.

On the other hand, anodized magnesium is more lightweight, making it the most suitable option in applications where weight is an issue.

• Anti-corrosive features

Anodized aluminum seemingly exhibits better anti-corrosive elements than anodized magnesium.

The former forms a natural layer that prevents corrosion, and anodization further augments the feature.

Anodized magnesium also has outstanding anti-corrosive features but is not as formidable as anodized aluminum.

• Melting point

Anodized magnesium has a relatively low melting point than anodized aluminum material.

How Do You Determine The Most Suitable Anodized Magnesium For Your Application?

When choosing the ideal anodized magnesium, it is fundamental to know the basic factors.

Such elements make it easy to select the most suitable material, and they include the following;

• Requirements for a specific application

Of course, different projects require different types of anodized magnesium.

Always make sure you look into the specifications of the applications to enable you to choose the most suitable material.

• Alloying element composition

Anodized magnesium is made from magnesium that contains different alloying materials.

Ideally, different alloying components are designed for specific applications, thus ensuring you pick the most suitable one.

• Anodizing method

Ensure you pick the anodized magnesium based on the particular anodizing method used for making it.

Essentially, different anodizing methods are used for making anodized magnesium suited for various projects based on the required properties.

• Cost

You should never overlook the price factor when determining the most suitable anodized magnesium for your needs.

Always go for what suits your budget as long as it presents the qualities ideal for your applications.

How Durable Is Anodized Magnesium?

Parts made from anodized magnesium alloy

Generally, the oxide layer, which forms on the surface of magnesium, gives the material relative durability.

It can last for many years, even when exposed to different mechanical conditions.

However, the specific durability is dependent on the layer thickness on the surface.

Thin layers, of course, based on conditions the part is exposed to, will have a shorter lifespan than one with a thicker layer.

Hence, it is advisable to ensure you choose the right anodizing method for your application that guarantees a relative service lifespan.

Can You Re-Coat Anodized Magnesium?

Yes.

You can always re-coat anodized magnesium, primarily through painting.

This material has excellent paint adhesion making it easy to re-coat.

Additionally, coloring increases the corrosion resistance and durability of anodized magnesium since it adds another layer to the surface.

How Do You Establish A Properly Anodized Magnesium?

You can use several ways to determine whether anodized magnesium is properly anodized.

However, the main practical methods you can easily use include the following;

• Check out the matte finish – A proper anodized magnesium always exhibits a unique matte finish. If your material doesn’t have such a finish, you may need to re-order another one.
• Conduct a scratch test – Use a coin or sharp object to scrape the surface material of anodized magnesium. If it creates scratch, then it implies the part is likely not fully anodized.
• Color spreading –perfectly anodized magnesium exhibits an even surface with consistent color dispersal.

Which Elements Should You Have In Mind When Designing Anodized Magnesium?

They are quite a few, but ideally fundamental to figure them out, and they include the following;

• Relatively thick anodic layers may reduce the fatigue life of parts, particularly if they incorporate Type III processes.
• It can be difficult to attain color matching, especially when dealing with multiple batches.
• To attain comprehensive corrosion protection, it would be ideal for sealing all the anodic layer pores.
• It is necessary to consider geometric changes for any magnesium parts to be anodized. This is vital, especially when using Type I and Type II processes.
• Various magnesium alloys may respond differently to anodizing processes; thus important to determine the most suitable process for each alloy.

What Are The Shortcomings Of Anodized Magnesium?

Some notable disadvantages of anodized magnesium include the following;

• In many instances, they require secondary sealing or treatment
• Usually costlier than other alternatives offering similar solutions
• The machinery cost for anodized magnesium can be a bit costly.

What Are The Main Applications Of Anodized Magnesium?

You can use anodized magnesium to do various projects in different industries, such as the following;

• Automotive industry for making wheels and seats among other components
• Power tools
• Consumer electronics such as laptops
• Cameras
• Aircraft parts
• Jewelry
• Consumer goods
• Light fixtures
• Medical devices

If you have any question on anodized magnesium, feel free to contact us.