THIN FILMS OF RHODIUM/IRON ALLOYS FOR WIDE RANGE THERMOMETRY

RESISTANCE THERMOMETERS WOUND OF WIRE MADE FROM DILUTE SOLUTIONS OF IRON IN RHODIUM HAVE PROVEN TO BE SUPERIOR IN SEVERAL WAYS TO EXISTING GERMANIUM AND PLATINUM RESISTANCE THERMOMETERS IN THE RANGE FROM BELOW 1K TO 800K, INCLUDING RANGE, STABILITY AND MAGNETIC FIELD EFFECTS. THE POTENTIAL FOR A SMALL, THERMALLY FAST AND PHYSICALLY ROBUST THIN FILM RESISTANCE THERMOMETER OF THE SAME MATERIAL IS EXAMINED. SIZE EFFECTS AND IMPURITY SCATTERING FROM THE IRON ARE CONSIDERED IN DETERMINING THE POSSIBILITY FOR MAINTAINING ANADEQUATE TEMPERATURE COEFFICIENT OF RESISTANCE TO MUCH LOWERTEMPERATURES THAN OBTAINED WITH THIN FILMS OF PURE PLATINUM.AN EXPERIMENTAL EFFORT IS PROPOSED TO SPUTTER SEVERAL ALLOY COMPOSITIONS AND THICKNESSES AND PERFORM RESISTANCE MEASUREMENTS AS A FUNCTION OF TEMPERATURE IN THE RANGE 1.4K TO 550K. THE SAME TYPE OF THERMAL SHOCK TESTING AS PERFORMED ON PLATINUM, GERMANIUM AND OTHER TYPES OF PRODUCTION THERMOMETERS IS PROPOSED AS A TEST OF FILM ADHERENCE AND STABILITY.