Analysis has been done using QPAC40® Polypropylene carbonate as a clean-burning binder for base metal electrodes in NKN and PZT Piezoelectrics.
The experiment was conducted by the Center for Dielectric and Piezoelectrics, Material Research Institute at Pennsylvania State University.
The QPAC40® allows a clean burnout at low temperature in N2 atmosphere. The QPAC40® allows the burnout to happen in a non-oxidizing environment at a low temperature.
The research at Penn State was conducted using the QPAC40® binder to create the tape. Traditionally, polyvinyl butyral, PVB has been used in both Ag/Pd and Ni co-fired multilayer actuators. This requires burnout to 400 °C. This temperature already surpasses the highest temperature of retaining the metallic state of both Cu and Ni.
To successfully prevent Ni and Cu form oxidation, clean burnout has to be accomplished at either in a low pO2 atmosphere or in a practically low temperature. With the conventional PVB system clean burnout cannot be attained. The high temperature needed for burnout and the high carbon residual levels caused poor results.
When the QPAC40® Polypropylene carbonate was used to create the tape, lower debind temperatures were possible and no detectable residue was left after burnout. The PVB system formed unwanted char while the QPAC®40 binder system developed propylene carbonate monomer which was vaporized without leaving any residual carbon.
This research article demonstrated that copper inner electrodes are extremely attracted as metal electrodes for co-firing with NKN. Further, the use of QPAC40® permits high densities and low dielectric loss multilayer piezoelectric structures.
This research complements other studies, which reveal that QPAC40® is an operative binder in tape casting. It results in a tape with superior green strength, as well as allows for the final sintered product to have excellent electrical properties because of the binder’s clean burnout properties.