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).
Corrosion tests performed on carburetter floats made from different materials.
| Identifier | ExFiles\Box 74\2\ scan0011 | |
| Date | 22th March 1921 | |
| R.R.199 (250F) (SD676 19-7-17) MP180865 COPY. BY.{R.W. Bailey - Chief Engineer} H15/EB22.3.21. RE CORROSION OF CARBURETTER FLOATS. Tests have been made during fourteen days on arsenical copper containing 0.4% arsenic, copper containing 0.03% arsenic, and nickel plated arsenical copper. The pieces of float have been immersed in Shell Mex petrol containing 10.0% benzole. Traces of moisture were also present, and the mixture of spirits contained 0.045% sulphur. The effect of minute traces of chlorides, sulphates, hard water, soft water and alkalies indicate that chlorides are most active in causing corrosion, though in the case of the arsenical copper sulphates had nearly as much effect. To generalise, it appears that the nickel plating would give the best results from the corrosion point of view, so long as the coating was an adherent one and chlorides were absent. Pure copper runs it very closely however, and it appears likely that it would be practically as good in practice if sufficiently stiff. Arsenical copper appears to be much more rapidly acted upon than the other two, and develops surface markings similar to those seen on floats which have been corroded badly in service. The corrosion appears to be associated with the sulphur in the spirit, since with more benzole, corrosion is accelerated, but minute quantities of moisture and salts also have a marked influence even by themselves in the course of time. The latter statement is based on previous tests. Hl. | ||