“…Temperatures below 1000°C would also enable the use of cheaper Ag contacts instead of the much more expensive Pd-or Ptcontaining ones [9][10][11][12][13][14][15]. Different approaches have been reported in order to prepare dense varistor ceramics with good I-U characteristics at temperatures below 1000°C, such as the use of fine starting powders with a high sinterability prepared by a polymerized complex method [16], a two-stage, low-temperature thermal processing [17,18], hot pressing [19] or the addition of low-melting glass frit [10,20]. They resulted in a high density of varistor ceramics; however, the breakdown voltages of the ceramics were still above 1000 V·mm -1 , which is much too high for most applications.…”