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).
The effectiveness of a corrosion inhibitor and strategies for managing corrosion in water systems with mixed iron and aluminium parts.
| Identifier | ExFiles\Box 150\3\ scan0364 | |
| Date | 21th February 1938 | |
| -5- (5) Corrosion Inhibitor - We are not satisfied yet that this corrosion inhibitor "No-Co-Ro{C. C. Rose - Export Manager}" really gives any advantage, particularly in an engine which is chiefly composed of aluminium. We shall be able to decide whether it has materially affected matters on a cast iron engine when 6.B.IV and 26.G.VI cars return from France, but at the moment we are not decided as to its value. Attached N.P.L. report on this inhibitor indicates that it does reduce iron corrosion but increases aluminium corrosion. The Laboratory, therefore, are endeavouring to check up on this increase of aluminium corrosion. SUMMARY. If possible, aluminium and iron in the same water system are to be avoided from the standpoint of corrosion; where their joint presence is inevitable it is essential to have no water loss and consequent replenishment, and if possible seal the system with a steam valve. Further, anodic oxidation is a valuable help in reducing corrosion and again should be used where iron and aluminium are both used in the water system. In the case of the project B.III engine where cast iron cylinder block will be used with an aluminium cylinder head, it will probably be desirable to use both anodic oxidation of the head and other aluminium parts and also a steam valve. We are accordingly going to endeavour to develop a cheap and effective simple steam valve. We think that anodic oxidation of the aluminium parts of the Ph.III water system should be standardised as soon as possible in order to obtain the benefit and experience of same on this car. The plant and solution will be needed later on B.50 so that the actual cost for Ph.III chassis will only be in the neighbourhood of 5/- per chassis when B.50 is in production. A corrosion inhibitor should be used in the cooling system, if and when we find an effective one. Rm{William Robotham - Chief Engineer}/Std. | ||