Screen printing is a standard procedure for applying metallic electrodes
to piezo ceramic. Various silver pastes are used in this process. After the
screen printing, these pastes are baked at temperatures above 500 °C and
adhesion of the electrodes is obtained by the burning on of the glass frit
contained. The typical electrode thickness is around 10 µm. With thin
ceramic plates, the effect of the glass frit must be taken into account. The
nature of these thick-film electrodes generally leads to a reduction of the
Electrode adhesion is around 5 Mpa.
Thin-film electrodes are applied by the the latest sputtering techniques. The
typical thickness of the metallization is in the range of 1 µm.
Shear elements, which are metallized in the polarized state, are always manufactured with thin-film electrodes.
PI Ceramic has highproductivity sputtering equipment which facilitates the application of electrodes made of metal alloys, preferably CuNi composites and noble metals such as gold. The achievable bondstrength values of the electrodes are similar to those of the thick-film electrodes.
Soldering is the usual way of making electrical contact with piezoceramic components. All of our standard metallizations are compatible with the use of lead-free solders. We recommend, for example, the use of a solder with the composition Sn 95.5% Ag 3.8% Cu 0.7%. All soldered contacts must be point contacts, and the specified soldering temperatures must be respected. The soldering time must be as brief as possible. Quick, punctual soldering at temperatures above the Curie temperature does not result in significant depolarization losses or degradation of the piezoelectric parameters.
The positive electrode is the one that is labelled (marked). This is done with a dot or a cross on the surface of the electrode or by a (reddish) coloring of the electrode itself.