Hard Chrome Plating & Decorative Chrome: What’s the difference?

Have you ever wondered what’s the difference between decorative chrome or hard chrome plating?

Chromium is about the same hardness in both decorative chrome and hard chrome plating, about 800 to 1000 VHN (which is incredibly heavy). The main difference is found in the thickness of the deposit.

For the decorative purpose of chrome, it is seated best on nickel, which adheres incredibly well to copper – the combination of all three offers possibly the best corrosion protection resistance available. Decorative chrome thickness can vary from anywhere between a few hundredths of a mil to one mil. The mirror finish will effectively only be as good as the finish that is on the surface before the chrome, so it’s all a very difficult process at times.

Mould Tool Polishing
An example of chrome plating

For the purpose of being functional, or take either take advantage of the extremely low friction that chrome holds or for building surfaces and pistons, hard chrome will be plated with a thickness anywhere between 1 to 50 mills.

When used as a bearing surface, chrome simply must be micro-finished, something which will then provide a level of friction much lower than any other metal when used against the likes of steel, iron, brass, bronze or aluminium alloys. There’s something that you mustn’t do; Do not use chrome against chrome. Chrome is much harder than casehardened steel, so we are then left with a perfect set-up for longwearing working surfaces. Chrome will resist pretty much all organic and inorganic compounds and acids, except hydrochloric acid.

For more on hard chrome plating, surface finishing & polishing, please visit our website.

The Top 10 Facts about Chrome (Metal)

 

Here are some facts about the almost mirror like metal.. Chrome as well as what you need to know If you want something coated in it.

First things first, what is Chrome?

The full name of Chrome is Chromium which is a Metal material, in most cases things are never usually made of solid chrome so when you hear of something which is chrome, what it is really is a thin layer of chrome (plating of chrome) on top of the object which in most cases is steel, aluminum, copper, brass, plastic or even stainless steel.

A top cause of occasional confusion is the fact that people tend to describe any shiny finish as “chrome” even when it really has nothing to do with chromium.

For example, brightly polished aluminum motorcycle parts are sometimes called ‘chrome’ by the lay person. This is because it’s not always easy to tell chrome plating from other finishes if the parts are not side by side.

 

Is all chrome plating almost the same, then?

Not always, as there are two different general applications for chrome plating which are hard chrome plating (called engineering chrome plating) and decorative chrome plating.

Hard Chrome Plating

Hard chrome plating or Industrial Chrome is chrome plating that has been applied as a  heavy coating (usually measured in thousandths of an inch) for wear resistance, lubricity, oil retention, and other ‘wear’ purposes.Some examples would be rollers, piston rings or motorcycle fork stanchions etc.

‘Hard chrome’ is not really harder than other chrome plating, it is called hard chromium because it is thick enough that a hardness measurement can be performed on it, whereas decorative chrome plating is only millionths of an inch thick and will break like an eggshell if a hardness test is conducted, so its hardness can’t really be measured directly.

 

Decorative Chrome Plating

Decorative chrome plating is often called nickel-chrome plating because it always involves electroplating nickel onto the object before plating the chrome (sometimes also involves electroplating copper onto the object before the nickel too). The chrome plating is exceptionally thin, measured in millionths of an inch rather than in thousandths.

When you look at a decorative chrome plated surface, for example a chrome plated wheel or even a car bumper, most of what you are seeing is actually the effects of the nickel plating. The chrome adds a bluish cast (compared to the somewhat yellowish cast of nickel), this then protects the nickel against tarnish, minimizes scratching, and symbiotically contributes to corrosion resistance. But the point is, without the brilliant leveled nickel undercoating, you would not have a reflective, decorative surface.
Restoration Work

When an item or object needs “rechroming”, this actually involves stripping the chrome, stripping the nickel (and the copper if applicable), then polishing out all scratches and blemishes, then plating with copper and mush buffing to squash copper into any tiny pits.

Where do you get your Hard Chrome plating? or Polishing in Birmingham? Polishcraft would be your best bet every time!