From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Laboratory examination of two chromium-plated parts for deposit thickness and porosity.
| Identifier | ExFiles\Box 88\5\ scan0063 | |
| Date | 21th June 1938 | |
| Rm{William Robotham - Chief Engineer}/Gry.{Shadwell Grylls} 256. H1/EA.2/SK.21.6.38. Laboratory. Re : Two Chromium Plated parts Submitted for examination. The Bentley wheel nut was examined for thickness of deposit and for porosity, with the following results. Deposits Copper - Flash deposit. Nickel - 0.00175". Chromium - Not measured. The steel from which the cap was made contained a considerable amount of slag. On the main surface of the cap, porosity was evident only at the edges of some of the letters. As previously pointed out, it is doubtful whether such a job would ever be entirely satisfactory, since burrs on the letters and small pieces of forging or heat-treatment scale, persist where the surface cannot easily be polished. The tubular specimen was found to have only 0.00075" thickness of nickel under the chromium. Rather extensive porosity was evident on this specimen, and it appeared to be associated with surface defects in the base material and the very poor finish applied to the steel before plating. The pores were very small and not easily visible on short term corrosion test. H1/EA. | ||