Net-shape ceramic processing as a route to ultrafine scale 1-3 connectivity piezoelectric ceramic-polymer composite transducers

Abstract

In this paper, we report on a new "net-shape" processing method for the fabrication of ultrafine scale 1-3 ceramic structures. We have used Viscous Polymer Processing (VPP), combined with a modified "lost mould" method to obtain lead zirconium titanate (PZT) bristle-blocks with feature sizes of 12 µm -100 µm and aspect ratios of the order of 3-10. Experimental, 1-3 piezo-composite transducer elements have been assembled and we report on their electrical impedance and pulse-echo behavior and demonstrate a close correlation with computer modeling. We conclude that the processing route we have developed has the potential to extend upwards the frequency range of piezo-composite material beyond existing limits.

1–3 piezocomposite design optimised for high frequency kerfless transducer arrays

“…Viscous polymer processing (VPP), in which high shear mixing is used to form a paste from ceramic powder, binders and solvent, has been developed to produce high density ceramic [6]. The ceramic paste is pressed into a mould and dried, ready for de-moulding and sintering.…”

1-3 Piezocomposites realised from small feature size, high aspect ratio, hot embossed moulds. Part II: piezocomposite fabrication

“…The k t was found to be 0.61, which is consistent with the typical values, of 0.60-0.75, for 1-3 piezocomposites (Smith 1991). This is improved over the k t of 0.52 for the previous work by Cochran et al (2004) and Abrar et al (2004) but is not as high as the 0.68 presented by Park et al (2003). The k t is dependent upon several factors including the volume fraction, material and composition.…”

“…The width of the pillars can be compared to the piezocomposite presented by Abrar et al (2004) and Cochran et al (2004). It can be seen that the pillars presented here are slightly larger, measuring 68.7 lm compared to the long axis of 65 lm and a short axis of 50 lm.…”

“…To avoid this, a mould replication step is necessary so that many moulds can be made cost effectively from a single master. Previous researchers have used CNC machining (Su et al 2002), X-ray lithography, hot embossing (Abrar et al 2004;Cochran et al 2004) and injection moulding (Park et al 2003) to fabricate their moulds. But only injection moulding and hot embossing can be considered as replication processes, and therefore candidates for a cost effective processing route.…”

“…Hot embossing has previously been discussed by Abrar et al (2004) and Cochran et al (2004). They produced a wide range of bristle blocks using moulds made by hot embossing and X-ray lithography.…”