Further examinations of carbon/polyesterimide thick-film resistors

Formulation of composite resistive pastes for fabrication of micro-heaters

“…Based on this first set of values, we decided that a 20% volume concentration in conductive filler was an adequate compromise between low resistivity and processability. Finally, we note the critical volume fraction for percolation is quite low < 4%, but wide critical fractions are found in the literature, even for graphite of low geometric anisotropy [4,5,7,10,12,13], which can be due to various processing factors such as aggregation, or even small debris [17].…”

“…Thermal cycling between 30 and 140°C of test resistors demonstrated that this final composite is more stable with temperature, although significant change is still observed in the 1 st cycle. Stability could be further improved by substituting part of the graphite with carbon black [12][13][14]. The presence of both fillers also in principle allows a lower resistivity at high loadings [7,13].…”

Tunneling-percolation origin of nonuniversality: Theory and experiments

“…This is illustrated in Fig. 1, where we have collected 99 different values of the critical exponent t and the critical threshold x c measured in various composites including carbon-black-polymer systems, oxide-based thick film resistors ͑TFRs͒, [27][28][29][30][31][32][33][34][35][36][37][38] and other metal-inorganic and -organic insulator composites. 26,[39][40][41][42][43][44][45][46][47][48] It is clear that, despite that many of the t-values reported in Fig.…”

Carbon/polyesterimide thick-film resistive composites – Experimental characterization and theoretical analysis of physicochemical, electrical and stability properties

“…The high structure Ketjen Black EC-DJ 600 (specific surface area 1270 m 2 /g, 4.8 ml/g oil absorption, spherical shape with 6 nm mean diameter), SAKAP-6 medium structure conductive carbon black (specific surface area 200 m 2 /g, 1.2 ml/g oil absorption, spherical shape with 30-40 nm mean diameter) and flaky-shaped graphite (0.2-0.7 lm thickness and the other two dimensions of about one order larger) have been used as the active phase [7][8][9]. Polyesterimide resin dissolved in N-methyl-2-pyrrolidone and a suitable catalytic agent served as the remaining component of the inks.…”