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).
Page from a journal discussing metallic and chemical coatings for engine parts, and new automotive developments.
| Identifier | ExFiles\Box 142\2\ scan0432 | |
| Date | 15th April 1939 | |
| METALLIC AND CHEMICAL COATINGS 495 to the surface coatings on rings, pistons, valve guides, rocker arm supports, etc. According to a statement by the Acheson Colloids Corp., the chief advantages in using colloidal graphite for this purpose are as follows: 1. Satisfactory dry lubricant in place ready to function on initial movement. 2. An agent which sets up resistance to oxidation by virtue of being impregnated in the pores adjacent to the non-oxidized metal immediately below the coating. 3. Lubricating properties which increase the life of the porous coating by reducing the friction which otherwise exists. 4. Combined treatment has the ability to hold an appreciable amount of oil. The graphite is held in place by the pores and in turn it is capable of holding a film of oil from two to four times the thickness of a film of oil held by untreated metal. So far as the future use of this treatment is concerned, there is evidence that colloidal graphite may be applied not only in treating the parts that go into the mechanism but also in the treatment of the equipment and tools used in producing automotive parts of various kinds. To round out this discussion we give below the trade names and descriptions of the coatings used by some of the leading piston ring manufacturers: “ALTINIZING”—electrolytic deposition of a tin-base alloy on rings by McQuay-Norris. “FERROX”—not strictly a surface coating, but a change in the structure of the surface metal by treatment in an electric surface at temperatures approximating 1,000 deg. F.{Mr Friese}, depending upon the material. This process was developed by Perfect Circle for piston rings, adaptation of the process being expedited by licensing its use for other applications. “SILCOAT”—an outgrowth of the black iron-oxide coating which results from the Heat-Shaping process by which tension is imparted to Pedrick piston rings. “Silcoat” is a still further conversion, by chemical process, of this black iron-oxide surface into a coating of silicon and carbon, said to be many times more effective in resisting wear than the oxide coating. It is applicable, however, only where parts have been subjected first to a heat treatment which brings the iron-oxide to the surface. “FERITEX”—a chemical sulfidizing procedure which imparts E-P characteristics to the contact surfaces has been adopted by American Hammered Piston Ring Div., Koppers Co. The process is licensed for use by the Standard Oil Co. of California. “GRAFOTOX”—a special Bonderized coating with Acheson colloidal graphite treatment, which is used by the American Hammered Piston Ring Division of The Koppers Company. It is of interest to note that this producer uses both Feritex and Grafotox processes. “GRANOSEAL”—a phosphatic surface treatment characteristic of Sealed Power piston rings. “GRAPHITOX”—special Bonderite coating with Acheson colloidal graphite treatment is featured on rings made by Muskegon Piston Ring Co. Finally, we may say that many manufacturers in the automotive industry are giving serious consideration to the adoption of surface coatings for wear-resistance and/or corrosion-resistance. In fact, during the course of this brief investigation, we contacted a number of organizations where experimental work to this end is in progress. It seems evident that the new technique will find still wider application during the course of the next few months. NEW DEVELOPMENTS film on the individual fibers, thus the pores of the fabric are not clogged and the free circulation of air is permitted. The finish makes Flexine fabrics smooth, more comfortable, and is said to nearly double their durability. New Solvent for “Piston Varnish” Discovery of an aromatic solvent compound which is said to quickly dissolve “piston varnish” has been announced by the chemical department of the Curran Corp., Malden, Mass. The new solvent is vaporizable at combustion temperatures and the saturated vapor, upon cooling and reaching the dew point, precipitates copious quantities of the hot tar solvent. Dissolved “piston varnish” and/or carbonaceous tars may be removed from the engine by draining the engine oil. According to the manufacturer, a normal dose of 32 ounces should be administered just before oil change time, then any residual film or deposits will be removed. (Turn to page 506, please) Resists Abrasion Discussing the high abrasion resistance of magnesium alloys, Leslie Brown of Magnesium Fabricators Division of Bohn Aluminum & Brass Corp., told recently of the experience of one prominent motor car company which uses magnesium alloys for its crankcase core box. “From one of these core boxes,” he said, “they have taken over 2,400,000 cores. This record is all the more remarkable because all of these cores are blown under an air pressure of from 100 to 125 lb. Thus, although there is literally a sand blasting action on the core box, the material is apparently impervious to wear.” Automotive Industries April 15, 1939 | ||