Abstract: A method of heat-treating a metal film for use as a resistor and the resulting product. The method involves heating the film in an oxidizing atmosphere for forming a protective oxide film on the metal film, removing adsorbed foreign elements therefrom, and changing the crystal structure thereof, and for a time sufficient to change the initial temperature coefficient of resistance to a desired value. The temperature for the heating when the coefficient is to be changed in the positive direction is a temperature in the range between the first and second critical temperature for heat treating in and above the third critical temperature. When the coefficient is to be changed in the negative direction, the temperature is between the second and the third critical temperatures for heat treating in air.

Abstract: A pre-treatment method for electroless plating of metal film resistors is provided. Said method is characterized in that a stabilized and uniform activating film is formed on the base material to be plated by sequential treatment of said base material with a stannous chloride (SnCl.sub.2) solution, a silver salt solution, a second stannous chloride solution and a palladium, a palladium chloride (PdCl.sub.2) solution. The resultant alloy film has improved resistance to exfoliation.

Abstract: Method for producing a metal film resistor by (1) treating a base material with a stannous chloride solution, silver salt solution and palladium chloride solution, respectively, (2) subjecting the thus treated base material to electroless plating in a bath having a pH of 9.5-10.5 containing specified amounts of cobalt salts, nickel salts, sodium hypophosphite and specific acetifying agents, at a temperature of 20.degree.-50.degree.C, (3) heat treating the resultant metal film under specified conditions, which are also effective to prevent oxidation of the film and (4) subjecting the heattreated metal film to a surface treatment under specified conditions, which are also effective to cause oxidation of the film.