METHOD FOR PREPARATION OF THE SOLDERABLE CONTACTING METALLIC LAYERS SN-PB-AG ON THE CERAMIC EDGES OF LAMELLAR STRUCTURE RESISRORS FOR SURFACE ASSEMBLING

摘要

The method for producing solderable contactant metallic Sn-Pb-Ag films on ceramic edges of film structured resistors, in particular used for surface mounting, consisting in immersing resistor edges in Ag or Pd-Ag contactant polymer paste, consisting in that the paste includes 0.09-0.12 parts by weight of epoxy resin, preferably on the basis of phenolphthalein with the molecular mass of 400-1200 and the epoxy number 0.15-0.60 : 0.03-0.04 parts by weight of melamine resin being a 90 per cent terpineol solution of bismuth and lead resinates at the ratio of 1-5 parts by weight of lead resinate per 1 part by weight of bismuth resinate; 0.72-084 pert by weight of silver flakes or silver with an addition of 5-10 per cent of palladium with granulation below 40 microns, the paste being diluted with terpineol in the quantity of 0.1-0.4 part by weight of terpineol per 1 part by weight of the paste, and then the resistor edges are immersed in the contact paste for 10-30 seconds at temperature of 18-25 degrees C, and then the contact paste layer is baked in a tunnel kiln for 30-60 minutes, the paste baking process being conducted by raising the baking temperature at the rate of 20-40 degrees/minute for 10-20 minutes, and the maximum baking temperature of 420-480 degrees C is maintained for 10-30 minutes, and then the obtained Ag or Pd-Ag contact layer is subject to the process of manufacturing the solderable layer by immersing it in hot solder consisting of 62 per cent Sn; 36 per cent Pb; 2 per cent Ag at temperature of 270 degrees C for 10 seconds.