Title :
Physics of zinc-oxide cryovaristors in high power switching applications
Author :
Thibodeaux, Rene J.
Author_Institution :
US Air Force Wright Aeronaut. Lab., Wright Patterson AFB, OH, USA
Abstract :
Recent work has shown that a ZnO ceramic used for a cryovaristor has a high thermal conductivity and enthalpy at liquid nitrogen temperatures (77 K), yet, unlike other varistor materials, retains the characteristic back-to-back Zener diode I-V relationship at 80 K. Measurements show that the thermal conductivity of the ZnO cryovaristor has a maximum value of 0.65 W/cm/K at 80 K and a value of 0.24 W/cm/K at 320 K. The enthalpy of the ZnO ceramic was determined to be 1186 J/cm3 at 80 K, with an upper adiabatic limit of 1215 J/cm3. Computational analysis shows that a variable-range-hopping model can explain the small temperature dependence of the prebreakdown
Keywords :
ceramics; enthalpy; semiconductor switches; thermal conductivity of solids; varistors; zinc compounds; ZnO cryovaristors; enthalpy; high power switching applications; thermal conductivity; upper adiabatic limit; variable-range-hopping model; Ceramics; Conducting materials; Conductivity measurement; Diodes; Nitrogen; Physics; Temperature; Thermal conductivity; Varistors; Zinc oxide;
Conference_Titel :
Power Modulator Symposium, 1988. IEEE Conference Record of the 1988 Eighteenth
Conference_Location :
Hilton Head, SC
DOI :
10.1109/MODSYM.1988.26285
