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Method for making piezoelectric ceramic/polymer composite transducers

  • US 5,340,510 A
  • Filed: 04/05/1993
  • Issued: 08/23/1994
  • Est. Priority Date: 04/05/1993
  • Status: Expired due to Term
First Claim
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1. A net-shape process for fabricating a fully dense ceramic preform for a piezoelectric or electrostrictive composite transducer exhibiting 1-3 or 2--2 connectivity, said process comprising the steps of:

  • preparing a homogeneous, granulated, thermoplastic powder/binder mixture comprising ceramic powder selected from the group consisting of strongly piezoelectric or electrostrictive ceramic materials and sufficient thermoplastic organic binder to render said mixture moldable by injection molding, said binder being selected to render said mixture thermoplastic during injection molding and to be nondestructively removed from said mixture by heating;

    forming a green body of said preform by injection molding said mixture in an injection molding apparatus comprising a preform mold which is a negative of said preform green body and cooling said green body in said preform mold sufficiently to be releasable from said preform mold as a self-supporting green body, wherein said green body comprises a planar ceramic base and a plurality of parallel ceramic elements integral with and extending perpendicularly from said base in a preselected array and fixedly supported in said array by said base, each of said elements having a shape selected from the group consisting of rod-like and lamellar;

    releasing said self-supporting green body from said preform mold;

    heating said released green body to a temperature of 300°

    -700°

    C. for a time sufficient to completely remove said binder from said green body; and

    sintering said binder-removed body at a temperature and for a time sufficient to densify said binder-removed body to at least about 95% of theoretical density to produce a fully dense preform.

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