Nickel is a great metal to cover other metals in. If it were at all possible it would be a great idea to make all metal things out of Nickel as it doesn’t tarnish or rust as easily as steel and iron. Sadly, the mining of Nickel is expensive and it is hard to find places where it is. The three largest Nickel mining sites are in Russia, Australia and Canada. All are in hard to reach areas.
The alternative that we have is to cover or plate the material we want to protect in a tin layer of Nickel. These Nickel Composites, like the one available from https://www.poeton.co.uk/advanced-treatments/apticote-460-nickel-composites are melted and then either sprayed on to, or the subject is dipped, into the Nickel Composites.
There are many things that Nickel is used to cover. Locks and Hinges that have to be constantly opened and closed are subjected to a high degree of friction. Bolts are covered as the need to stay strong holding something in place. Radiator pipes are also covered as they pass hot water through a system and they are exposed to air. Air and water being the two main causes of rust and corrosion.