Experimental investigations have been carried out to study the variations of Microstructure and Temperature Coefficient Resistance occurring in Fe-clay based composite resistors. The resistors were produced from natural materials taken from Ibadan , and fabricated by a compaction method. The pressure of the mould = 1.00 ± 0.02 x 107 N / m2. The resistors have a constant thickness of 3.5 mm and varying lengths ranging from 3.00 mm to 10.00 mm. The resistors of composition 60 wt%Fe to 90 wt%Fe were subjected to varying annealing schedules, (i.e. varying peak firing temperatures ranging from 100 ^oC to 1000 ^oC and firing times from 5 mins to 240 mins. Most of the resistors fabricated with the Ibadan clays have negative TCR values. Their values are as low as ± 2 x 10 ppm / ^oC which are comparable with thermistors and other standard resistors. Scanning electron microscope model 1990 at IITA Ibadan was use to do the analyses. From the micrographs, it could be suggested that relevant interactions of both conductive and resistive films took place, which in turn control the value of the resistance of the resistors.

Keyword: Temperature Coefficient Resistance, Microstructure, composite resistors, Conductive and Resistive films

• Full Text: PDF(200Kb)
• Full Text: HTML