The first nickel/silicon carbide coatings in the automotive industry were applied on the cylinders of Wankel motors (rotary motors) in 1966. The Japanese industry (Suzuki) adopted the coating on motorcycles in 1978. Around 1980, the French automotive industry (Peugeot Citroën) used the coating for certain specific applications. Nowadays, use of the process has spread to all motor sports, including the F1, karting, and motorcycles.
A few words concerning the process :
The nickel/silicon carbide compound coating (commonly known as Nikasil, with a number of different spellings) is prepared through electrolysis. It consists of an electrolytic nickel matrix and minute particles of very hard silicon carbide (3,000 Vickers) spread throughout this matrix. These particles give the coating exceptional resistance to wear and an extremely low friction coefficient.
After many years of research, Revaltec improved the original process and designed its own coating, Revasil. The improvement of the process is first about the reliability of the ranges of surface preparations permitting perfect adhesion on such supports as aluminium alloys, cast iron, etc. This phase is essential, for “of what worth is the best coating if it won’t stick to the surface?” Research then focused on the coating itself. Consisting of an electrolytic nickel matrix (the binder) and minute particles of very hard silicon carbide, its optimal characteristics are obtained under the following conditions :
Elevated hardness of the nickel matrix, avoiding decohesion of the carbide grains, homogeneous distribution and exact size of the particles, degree of purity of the powders used to avoid parasitic inclusions, significant silicon-carbide proportion in the matrix (volume greater than 13%), as this proportion directly determines the material’s resistance to wear. Revaltec has conducted in-depth research on these crucial points to give offer state-of-the-art technique : Revasil. This technique, which has been used successfully on competition motors, can also be applied elsewhere : Cylinders used in ULM’s, speedboats, jet skis, compressors, and other parts requiring high mechanical characteristics.