Ford Motor Company Limited

Leonard G Cordone

John R Morgan

William A Donakowski

Yeshwant P Telang

A method is disclosed for fabricating a rotor housing for a rotary internal combustion engine. A conductive mandrel is prepared having an outer surface complimentary to the resultant rotor housing inner wall, the mandrel is provided with an exterior surface smoothness in the range of 4-12 r.m.s. A functional coating of a composite particle wear-resistant material is electrolytically deposited onto the mandrel (acting as a cathode) to form an assembly, the exposed surface of the assembly is controlled to have a roughness characterized by projections no less than 0.030 inches and concentrated in a number no less than 5/cm.sup.2. The assembly is placed in a die-casting machine where a molten metallic medium is cast thereabout forming a casting which is substantially mechanically locked to the assembly. The mandrel is then stripped from the coating to leave the resultant rotor housing. The resultant rotor housing is characterized by wear-resistant inner surface which is almost totally non-porous, its as-deposited surface roughness is at least 24 r.m.s., has a high heat transfer coefficient, is non-brittle and experiences no micro-cracking due to heat checking in service. The composite is economically fabricated and is strongly adherent.

Composite rotor housing with wear-resistant coating

A method is disclosed for preparing a coated rotor housing useful in a rotary internal combustion engine. A first mandrel is defined from conductive material such as a chrome-bearing steel. The outer surface of the first mandrel is shaped to be the mirror image of the resultant internal surface of the rotor housing; the first mandrel material is passivated preferably by the use of boiling water to form a chrome oxide material on the outer surface to prevent adhesion of surrounding coated materials. A thin, composite-particle wear-resistant coating is electrolytically deposited on to the first mandrel to form an assembly. The wear-resistant coating is preferably comprised of nickel carrying embedded silicon carbide particles. The first mandrel is stripped from the deposited thin coating leaving a self-supporting liner or sleeve, the liner may be used in its unitary form or may be sliced into smaller liner bands for separate processing. The liner is placed about a brother mandrel (identical in shape to the first mandrel, but previously preheated by use in the die-cast machine) and together they are inserted into a die-cast machine. Molten aluminum is supplied to the machine for casting about said liner to define a complete housing construction, the liner offering high wear-resistance.

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Allen Park, MI, United States of America

Leonard G Cordone