PURPOSE: To prepare the titled paste which is inexpensive and provides an electrical connection not susceptible to changes with time, by treating base metal powder in a specified process for removal of surface oxides and mixing the powder with a resin in an inert gas atmosphere.
CONSTITUTION: Base metal powder (e.g. copper, nickel or iron in powder) is dipped in an organic solvent soln. of an organic acid (ester, oxime), e.g. fatty acid or phosphonic ester, for removal of metal oxides deposited on the surface. The powder is washed with a low-boiling organic solvent (e.g. hexane) so that pick-up of the organic solvent used above may be reduced to below about 1%. The powder is dried in an inert gas atmosphere and is mixed into an organic material (e.g. epoxy or xylene resin) to prepare the electrically conductive paste.
KUMAGAI MASASHI
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