Manufacture of microporous metallic tubes consisting mainly of nickel

Claim 1

THE METHOD OF MAKING A THIN-WALLED MICROPOROUS TUBE WHICH COMPRISES STARTING FROM A POWDER OBTAINED BY REDUCTION OF A NICKEL SALT OF THE GROUP CONSISTING OF NICKEL FORMIATE AND NICKEL OXALATE AT A TEMPERATURE RANGING FROM 150 TO 750*C. AT ATMOSPHERIC PRESSURE IN A REDUCING ATMOSPHERE, ADDING WATER TO THE POWDER THUS OBTAINED TO FORM A PASTE AND CRUSHING PASTE UNTIL THE NICKEL PARTICLE AGGLOMERATES HAVE BEEN DESTROYED, LEAVING ONLY GRAINS THE MEANS DIAMETER OF WHICH IS OF AN ORDER OF MAGNITUDE NOT HIGHER THAN 0.1 MICRON, MIXING WITH THIS PASTE A BINDER OF THE GROUP CONSISTING OF GUM TRAGACANTH AND ALGINATES SO THAT SAID GRAINS ARE COATED INDIVIDUALLY WITH SAID BINDER, EXTRUDING THE PASTE THUS OBTAINED THROUGH FINE NOZZLES TO FORM VERMICULAR THREADS, SAID THREADS BEING REAGGLOMERATED INTO A PASTE AND THIS LAST MENTIONED PASTE BEING AGAIN PASSED THROUGH SAID NOZZLES, THIS LAST OPERATION BEING REPEATED A PLURALITY OF TIMES, ADDING TO SAID VERMICULAR THREADS, BETWEEN AT LEAST SOME OF THESE REPEATED EXTRUSION OPERATIONS, A BINDER OF THE GROUP CONSISTING OF GUM TRAGACANTH AND ALGINATES SO AS TO FORM A PASTE, EXTRUDING THE LAST MENTIONED PASTE TO GIVE IT THE FORM OF A TUBE, THIS LAST MENTIONED EXTRUSION BEING EFFECTED UNDER A PRESSURE RANGING FROM 600 TO 1000 KGS. PER SQ. MM. OF EXTRUSION AREA, DEHYDRATING AND DRYING SAID TUBE, PLACING SAID TUBE ON A SMOOTH CYLINDRICAL SUPPORT OF A DIAMETER CORRESPONDING TO THE DESIRED INNER DIAMETER OF THE FINISHED TUBE, AND SUBJECTING THE DRIED TUBE TO A SINTERING TREATMENT, PERFORMED AT A TEMPERATURE RANGING FROM 500 TO 900* C. FOR A TIME RANGING FROM 30 TO 90 MINUTES.

Claim 2

THE METHOD OF MAKING A THIN-WALLED MICROPOROUS TUBE WHICH COMPRISES STARTING FROM A POWDER OBTAINED BY REDUCTION OF A NICKEL SALT OF THE GROUP CONSISTING OF NICKEL FORMIATE AND NICKEL OXALATE AT A TEMPERATURE RANGING FROM 150 TO 750*C. AT ATMOSPHERIC PRESSURE IN A REDUCING ATMOSPHERE, ADDING WATER TO THE POWDER THUS OBTAINED TO FORM A PASTE AND CRUSHING PASTE UNTIL THE NICKEL PARTICLE AGGLOMERATES HAVE BEEN DESTROYED, LEAVING ONLY GRAINS THE MEANS DIAMETER OF WHICH IS OF AN ORDER OF MAGNITUDE NOT HIGHER THAN 0.1 MICRON, MIXING WITH THIS PASTE A BINDER OF THE GROUP CONSISTING OF GUM TRAGACANTH AND ALGINATES SO THAT SAID GRAINS ARE COATED INDIVIDUALLY WITH SAID BINDER, EXTRUDING THE PASTE THUS OBTAINED THROUGH FINE NOZZLES TO FORM VERMICULAR THREADS, SAID THREADS BEING REAGGLOMERATED INTO A PASTE AND THIS LAST MENTIONED PASTE BEING AGAIN PASSED THROUGH SAID NOZZLES, THIS LAST OPERATION BEING REPEATED A PLURALITY OF TIMES, ADDING TO SAID VERMICULAR THREADS, BETWEEN AT LEAST SOME OF THESE REPEATED EXTRUSION OPERATIONS, A BINDER OF THE GROUP CONSISTING OF GUM TRAGACANTH AND ALGINATES SO AS TO FORM A PASTE, EXTRUDING THE LAST MENTIONED PASTE TO GIVE IT THE FORM OF A TUBE, THIS LAST MENTIONED EXTRUSION BEING EFFECTED UNDER A PRESSURE RANGING FROM 600 TO 1000 KGS. PER SQ. MM. OF EXTRUSION AREA, DEHYDRATING AND DRYING SAID TUBE, PLACING SAID TUBE ON A SMOOTH CYLINDRICAL SUPPORT OF A DIAMETER CORRESPONDING TO THE DESIRED INNER DIAMETER OF THE FINISHED TUBE, AND SUBJECTING THE DRIED TUBE TO A SINTERING TREATMENT, PERFORMED AT A TEMPERATURE RANGING FROM 500 TO 900* C. FOR A TIME RANGING FROM 30 TO 90 MINUTES.