He tried adding a variety of other metals to create a steel alloy that had better resistance and knew of the effect that adding chromium to steels had – this was already being used in the manufacture of aeroplane engines and Brearley found one ‘alloy that was difficult to examine microscopically because the etching processes used to prepare the samples for examination were far less effective than usual – …. surely an alloy with better corrosion resistance !. Stainless steel now has around 12% of Chromium added – so how does this make a difference ?