Chrome-plated aluminum

Steel and of course aluminum parts are often much more appealing when they are high glossy. There are different techniques available. One of these is the chrome plating of aluminum. In the following article we have summarized for you what is important in the chrome plating of aluminum.

Chrome plating exclusively by the specialist company

First of all, however, we must say that you yourself will hardly have the opportunity to chrome-plate aluminum and other metals. The effort is extremely high, in addition, acids and alkalis must be used in large basins. The laws are likely due to the toxicity of chrome, for example, make a dash through the bill.

The steps in chrome plating aluminum

Nevertheless, it is of course worth knowing how chromium plating works. But this process also reveals the question of whether it is actually necessary to chrome an aluminum part, because the steps are structured as follows:

  • Stain or strip aluminum
  • Metal rust if necessary (acid bath)
  • Polish aluminum
  • Copper aluminum
  • Polish aluminum
  • Nickel-plated aluminum
  • Polish aluminum
  • Chrome-plated aluminum

Polishing as an important step

As you can see, polishing aluminum is an important step in chrome plating. The polishing of aluminum is nothing more than a high-gloss compacting of the workpiece. Only by polishing, a gloss can be achieved, which comes in its intensity close to the gloss of aluminum. Incidentally, with stainless metal parts, if necessary, a hydrochloric acid bath is also added for rust removal after pickling.

The copper layer ensures better adhesion

After pickling the aluminum this is already intensively polished. The surface must literally be mirror-smooth, otherwise you will see every little scratch. Then the component is copper-plated in a galvanic bath (with current). The coppering of the aluminum is important because components of the aluminum alloy are not compatible with chromium and therefore the chromium would peel off very quickly.

After coppering and nickel-plating, polish again

Subsequently, the aluminum component is then polished again to a high gloss. Now, in a truly perfect execution, the nickel plating of the component follows. This step is based on electroplating. Now the aluminum workpiece is polished again. The surface must be absolutely flawless, otherwise in the chrome layer later every irregularity is clearly visible - like the famous dust grain in a paint job.

Finally, the aluminum comes into the galvanic chrome bath

The chrome is also applied by electroplating in a chrome bath. The chromium layer is thinnest at around 2 μm (0.002 mm). The copper layer can be up to 60 microns. After the chrome bath, the now shimmering yellow component is rinsed with clear water and now receives its typical chrome shine. The coppering or even gilding of aluminum is carried out according to the same procedure.

Tips & Tricks

If you want to chrome-plate components on vehicles, ie motorcycles and cars, you must observe the regulations. Not every component may be chrome plated. This concerns, for example, the frames of motorcycles or a trailer hitch on the car. In addition, the operating permit may expire if a weld seam is surface-compacted or polished to the rest of the surface, since the fracture strength can be influenced thereby.

Video Board: How to Polish Aluminum to Shine like Chrome-4yrs Later