THERMAL CONDUCTIVITY, DIFFUSIVITY PROBE DEVELOPMENT

A NEW TYPE OF PROBE AND ASSOCIATED COMPUTING INSTRUMENT ARE PROPOSED FOR QUICKLY MEASURING THERMAL PROPERTIES OF SOLID MATERIALS. THE PROPOSED COMBINATION IS BASED ON A MINIATURE THIN FILM HEAT FLUX SENSOR RECENTLY DEVELOPED AT VIRGINIA TECH. THE NEW PROBE ENABLES THE THERMAL CONDUCTIVITY AND DIFFUSIVITY OF SOLID MATERIAL SPECIMENS TO BE MEASURED SIMPLY AND RAPIDLY. AT THE END OF THE PROBE WILL BE A HEAT FLUX SENSOR AND TWO THIN FILM THERMOCOUPLES, APPLIED TO IT BY A MASKED SPUTTERING PROCESS. TO MEASURE THE THERMAL PROPERTIES OF A MATERIAL SPECIMEN, THE PROBE AND SPECIMEN, INITIALLY AT DIFFERENT TEMPERATURES, WILL BE PLACED ABRUPTLY IN CLOSE THERMAL CONTACT BY A MECHANICAL REGISTRATION DEVICE. THE RESULTING FLOW OF HEAT AND THE RAPIDLY CHANGING SURFACE TEMPERATURES OF THE SPECIMEN WILL BE TRANSDUCED INTO TRANSIENT ELECTRICAL SIGNALS. THESEWILL BE MEASURED AND RECORDED AS FUNCTIONS OF TIME. A METHOD FOR COMPUTING THERMAL CONDUCTIVITY AND DIFFUSIVITY FROM THE SIGNALS WILL BE DEVELOPED. A PHASE II PLAN FOR DEVELOPING THE COMPUTING INSTRUMENT ITSELF IS OUTLINED.