MICROSTRUCTURAL CONTROL IN SILVER-TIN OXIDE CONTACTS

MATERIALS WITH MULTICOMPONENT ULTRAFINE MICROSTRUCTURES ARE OF INCREASING INTEREST FOR USE IN CERMETS AND METAL MATRIX COMPOSITES. THIS PROPOSAL SUGGESTS A NEW APPROACH TO ULTRAFINE MICROSTRUCTURES AND TO A NOVEL PROCESS FOR THEIR PREPARATION. THE PROCESS INVOLVES ELECTROLESS PLATING OF A METAL ON COLLOIDAL NUCLEI. SILVER-TIN OXIDE FOR USE IN ELECTRICAL CONTACTS IS AN EXAMPLE OF THE KIND OF PRODUCT WHICH MIGHT BE MADE BY THE NEW PROCESS. BROADLY, ELECTROLESS PLATING MIGHT BE USED TO COAT OXIDES, METALS, OR IN GENERAL, COLLOIDAL PARTICULATES WITH A SECOND METAL. THE ONLY LIMITS ON THE SECOND METAL ARE THAT ITS SALTS MUST BE SOLUBLE AND THAT THEY CAN BE REDUCED TO METAL FROM SOLUTION. MICROSTRUCTURAL CONTROL IN THE RANGE OF 5 TO100 NM SHOULD BE POSSIBLE. THIS CONTROL WILL BE DEMONSTRATED IN THE SILVER-TIN OXIDE SYSTEM. THE PRINCIPLES OF ACCRETION OF A DENSE COATING ON COLLOLIDALNUCLEI IS THE BASIS FOR THIS STUDY.