Verwendung eines ferroelektrischen keramischen Werkstoffs für die Informationsspeicherung bei elektrostatischen Druckverfahren

A novel ferroelectric ceramic material comprises a ceramic perovskite solid soln. contg. one or more group 1 and 2 components, the group 1 components being: PbTiO3 (PT), BaTiO3 (BT), Pb(Fe1/2Nb1/2)O3 (PFN) and Pb(Zn1/3Nb2/3)O3 (PZN); and the group 2 components being: Pb(Mg1/3Nb2/3)O3 (PMN), Pb(Ni1/3Nb2/3)O3 (PNN), Pb(Fe2/3W1/3)O3 (PFW) and Pb(Mn1/2Nb1/2)O3 (PMnN). The amounts of the components of the two groups in the solid soln. are given by the mathematical equation: ((j) sigma (i = 1)) xi multiplied by Tci = TcM; where Xi = molar fraction of the 'i'th component; Tci = Curie point of the 'i'th component; and TcM = Curie point of the solid soln. (50 - 100 deg.C). USE - E.g. as a printing roller surface layer for information storage in electrostatic printing processes. ADVANTAGE - The material has high remanent polarisation combined with appearance of surface charges, easy polarisability esp. at 50 Hz (Pr is greater than 13muC / cm2 at 50 Hz), an almost rectangular hysteresis loop, a h igh insulation resistance of more than 1010 ohm cm, low variation of coupling factor and a coercive field strength of less than 200 V / mm.