Pyrolytic process for producing a band-shaped metal layer on a substrate

A pyrolytic method for the production on a cylindrical carrier member of resistors having a band-shaped resistance layer and a contact area at the ends thereof, comprising:

• surrounding a surface of the carrier member to be coated with a first fluid mixture of at least one thermally decomposable metal compound and a carrier therefor;
• substantially simultaneously heating only precise surface areas of said carrier member by a laser beam or an electron beam to a temperature slightly above the decomposition temperature of said metal compound, rotating said carrier member about a vertical axis thereof and axially moving said carrier member along the vertical axis thereof whereby a band-shaped helical metal deposit forms only on said precise surface areas of the carrier member;
• removing said first fluid mixture from about the carrier member and stopping said axial movement of the carrier member while maintaining the rotational movement thereof;
• surrounding the surface of such carrier member with a second fluid mixture of at least one thermally decomposable metal compound and a carrier therefor;
• heating only precise surface areas of the carrier member by a laser beam or an electron beam to a temperature substantially above the decomposition temperature of the metal compound in the second fluid mixture whereby a band-shaped cylindrical metal deposit forms only on said precise surface areas of the carrier member so as to define spaced metal contact areas on said helical metal deposit;
• and
• relatively quickly cooling the resultant carrier member with metal deposits thereon so as to form discontinuities in the carrier member for separating the helical metal deposits with the spaced contact areas thereon into individual resistors having contacts at opposite ends thereof.