| 摘要 |
<p>Piezo-ceramic articles, in particular small piezo-ceramic tubes, are metallised, in which the piezo-electric sintered material consists of lead zirconate/titanate and, to obtain a piezo effect, the small hollow-cylindrical tube must be coated on the inside and outside in the radial direction with conductive layers. Such small tubes have hitherto been individually provided manually with metallic layers. Currentless metallisation, though promising, has hitherto led to unsatisfactory results, since the metal layers were not resistant to stripping and, because of the increased contact resistance, higher voltages were required to obtain the piezo effect. According to the invention, the workpiece is subjected in a separate process step before the metal coating to an ultrasonic treatment in an alkaline solution containing a wetting agent, optionally preceded by ultrasonic treatment in water which likewise contains a wetting agent. An alkali metal carbonate or hydroxide and/or an alkali metal phosphate is preferably used for the alkaline solution.</p> |
