Bell Telephone Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

Western Electric Inc.

Richard Lewis Cohen

Ronald Lee Meek

Kenneth William West

A large number of applications exists for measuring the resistivity or other properties of ferrous and nonferrous metals, including matching alloys to ensure weld compatibility and measuring weld size to estimate weld strength. In the present invention, a DC current-reversal technique allows for accurate electrical measurement with a 4-point probe, alleviating problems due to surface potentials, thermal effects, and eddy currents that previously rendered such measurements inaccurate. Estimates of thermal conductivity, flaw size and location, among others, can also be obtained.

Precision nondestructive testing of metals

A gold plating process is described in which gold concentration is monitored by a radioactive excitation procedure. This procedure for measuring gold concentration requires no chemical manipulation and yields immediate results. The procedure can be adapted to continuous concentration measurement for use in automatic control of gold concentration in a gold plating procedure.

Gold monitoring procedure

A process is described for the electroless deposition of metals on nonmetallic surfaces. After pretreatment of the nonmetallic surface so as to obtain a finish suitable for deposition of sensitizers and activators, the nonmetallic surface is exposed to a sensitizing solution and thereafter in a separate step to an activation solution. The surface is then washed with an aqueous alkaline solution prior to immersion in the electroless plating solution. The separate sensitization and activation steps are particularly suitable where the sensitizing step is also used for pattern generation. The inclusion of the aqueous alkaline wash after the activation step both protects the electroless plating bath from contamination with sensitizer and activator, and also insures a short initition time. Short initiation times are highly desirable especially in the production of electronic circuits because highly uniform metal platings are insured, manufacturing time is considerably reduced and reliability is increased.

Process for electroless plating using separate sensitization and

A process is described for the electroless deposition of metals on nonmetallic surfaces. The process involves pretreatment of the nonmetallic surface so as to obtain a surface finish suitable for deposition of colloidal sensitizers which catalyze electroless metallic deposition. The nonmetallic surface is then exposed to a colloidal catalyst solution (typically SnCl.sub.2 /PdCl.sub.2) followed by an acid rinse. On completion of this surface activation procedure, the surface is exposed to a bath for the electroless deposition of metal. This procedure, which differs from that traditionally used, insures more reliable catalysis for electroless deposition of metals with shorter initiation times and is simpler in procedure and lower in cost.

Growing community of inventors

Berkeley Heights, NJ, United States of America

Richard Lewis Cohen