Application of the pyroelectric sensor for study of porosity effect on thermal diffusivity
of nickel copper zink ferrite
An investigation was carried out to study the effect of the porosity on thermal diffusivity of
Nickel Copper Zinc Ferrite. The experimental technique employed to measure thermal
diffusivity was the photoflash technique, and the measurements were carried out at room
temperature. The heating source consists of camera flash having approximately 5ms pulse
duration and a thin film of polyvinylidene difluoride (PVDF) attached to the back of the
samples was used as detector. Six different porosity levels were obtained by varying the
grinding time following the presintering process and preceding the sintering process at
1350°C. The porosity range obtained for the Ni0.3Cu0.1Zn0.6Fe2O4 samples was 1.8-7%.
The thermal diffusivity was determined from the experimental thermal transient signal. For
the fitting of the experimental results, the analytical model used was based on the
approximation that the pulse duration of the camera flash can be considered as Dirac-δ
function. Thermal diffusivity values for Ni0.3Cu0.1Zn0.6Fe2O4 samples were in the range
(7.8-8.7) × 10-7 m2/s.
Keyword: Porosity; Nickel; Copper; Zinc; Ferrite; Thermal diffusivity; Cameras;