Anodising vs. Electroplating: How to choose the right finish for your parts

By Protolabs

In the world of metal finishing, Anodising and Electroplating stand as formidable contenders, each wielding its own unique set of attributes to enhance the appearance, corrosion resistance, and durability of metal parts. To help you understand which finish is right for you, let's dive into these two surface treatment processes and uncover the secrets to choosing the perfect finish for your prized parts.

anodised parts

Understanding Anodising

Anodising is primarily known for its treatment of aluminium alloys, however, that doesn’t rule out other metals, such as titanium, which is also suitable for anodising.

The process combines part immersion and electrical currents and results in the creation of a protective oxide layer. To put it simply, imagine your aluminium part taking a tip in a bath. The bath is filled with electrolytes and with the support of an electrical current an oxide layer forms on the part. This oxide layer provides your part with reliable protection from corrosion.


How it works

  1. Part is cleaned and rid of contaminants.
  2. One end of the part connects to the positive terminal (making it an anode).
  3. Part is dipped into acidic electrolyte solution.
  4. A separate electrode takes on the role of the cathode.
  5. The electrical current is introduced.
  6. Metal ions interact with the oxygen ions.
  7. A protective oxide layer is formed on the metals surface.

Imagine your part emerges wearing a self-healing, corrosive resistant armour.

Benefits of Anodising

Anodising brings with it a multitude of advantages, from heightened corrosion resistance and durability to a variety of aesthetic options.
you want a part with increased resistance to abrasion? A lower coefficient of friction? And/or vibrant colours? Anodising might be an option for you.

Here is a breakdown of the key benefits anodising provides,

  • Corrosion Resistance of course right at the top of the list is corrosion resistance. The oxide layer that anodising produces shields the metal part from environmental factors.
  • Enhanced Durability Not only does the oxide layer provide wear-resistance but also improved hardness. Naturally extending the lifespan of metal parts.
  • Aesthetic Options make it perfect for decorative applications, allowing you to play with the colour of your part.
  • Lower Coefficient of Friction allowing for smoother sliding, reduced wear, and improved efficiency.
  • Electrical Insulation is ideal for electronic applications, anodising aluminium displays electrical insulating properties.
  • Lightweighting makes it perfect for weight-critical applications in industries such as aerospace.
  • Thermal Insulation is offered to a degree by anodised aluminium, thanks to its oxide layer.


Understanding Electroplaying

So now you know about anodising, what about electroplating?

Like anodising, electroplating is an electrochemical process and similarly involves a cathode, anode and electrolyte solution.
A surge of electricity introduced to the solution encourages the metal ions to move towards the cathode. It is at the cathode that they transform into a layer on the substrate’s surface. The thickness of the plated layer produced here is the result of the process’s duration.


How it works

  1. One end of the part is connected to the negative terminal (making it a cathode)
  2. Part is dipped into an electrolyte solution.
  3. The material used for plating takes on the role of the cathode.
  4. The electrical current is introduced.
  5. Metal ions from the cathode are attracted to the anode.
  6. A protective/ plated layer forms on the metal surface.

Benefits of Electroplating

Electroplating offers decorative finishes, corrosion resistance, and the ability to add conductivity to a previously non-conductive material. It also produces parts with smooth, shiny finishes and increases the part’s longevity.

Here is a breakdown of the key benefits anodising provides,

  • Decorative Finishes elevating the visual appeal of the part, offers smooth, shiny parts.
  • Corrosion Resistance to enhance the lifespan of the metal part by adding a protective layer (as anodising does).
  • Precision control coating thickness for consistent, reliable results.
  • Surface Hardness strengthens parts. Increased hardness means that they are strong against wear and damage.
  • Conductivity enables originally non-conductive materials to conduct.
  • Lubricity improves functionality by reducing friction in the electroplated parts.

Choosing the Perfect Finish: Anodising or Electroplating?

So now you’ve heard how they work and what they offer, hopefully you have a better idea of, which service might be best for you. When it comes down to deciding it is much an art as it is a science. Anodising is the go-to for aluminium, whilst electroplating offers versatility with a wider range of materials. Your choice should come down to your part and how you intend to use it.