I Protective Coatings

摘要

It is always humbling to discover that some technical explanation that always seemed sensible and was never questioned, is later found to be wrong. Those of you of my era should remember learning at school about the gaps that were necessary in railway rails, to allow for expansion during hot weather. We knew metals expanded when heated so this made sense. However, they discovered more recently that the rails were quite capable of absorbing this expansion, and rails are now laid in continuous lengths. The 'clicketty-click' of rail travel has been consigned to history. It is not that our text-books nor teachers set out to deceive us, it is just that what seemed like a reasonable explanation did not stand up to scrutiny.