As we know, the resistance of a padlock to break-in attempts is as important as the potential lifetime of the product (i.e. rust-proof), but which factors make a padlock ready to best deal with these circumstances? 

> Nickel plating / chrome plating = longer life. Is this always true?

It depends. 

Chemical treatments generally contribute towards making the padlock shackle (and also the body, in “marine” models) more resistant to oxidation and rust. 

In particular, copper plating (which is the most “hidden” treatment as it is the first to be carried out) is fundamental, as it improves the fixing of the subsequent nickel plating and chrome plating treatments which protect the padlock from corrosion and rust. Precisely because it is invisible to the naked eye, many cheaper productions avoid copper plating, nickel plating and/or chrome plating treatment directly. 

This saves production costs, but does not offer a good service to users, since it significantly increases the possibility that the surface nickel plating and/or chrome plating will tend, even in a short time, to flake or swell into small bubbles. 

In these cases the corrosion protection is quickly lost and the cause can be found in the imperfect cleaning of the metal surfaces before chemical treatments and/or the lack of copper plating treatment. 

The video shows the steps for copper plating, nickel plating and chrome plating of the armour of the padlocks (up to min. 4): 

Precisely in order to avoid these risks, Viro not only perfectly degreases and cleans the components which will be subjected to chemical treatments, but always starts them with a double pass of copper plating. In light of these points, hearing that a padlock, or part of it, is nickel plated and/or chrome plated is not in itself synonymous with durability and rust-proof. 

The anti-corrosion chemical treatments become really useful, however, only if the internal mechanism has also been designed and built with good quality components, so that in addition to being an aesthetically “clean” padlock its operation is also able to withstand both the normal atmospheric agents to which it would be subjected if placed in an outdoor environment and extreme climatic conditions.