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Edgars FREDENFELDS


Edgars FREDENFELDS

Founded and created the Research School of the Ceramics of Segneto and Piezoelectrics in Riga. He has studied the structures and dielectric properties of titanate, niobate and ferrite. He is the author of approximately 100 inventions.

Born: July 9, 1922, Pskov, Russia
Died: February 23, 1988, Riga, Latvia






Interests in inventing:

  • Modification of piezoceramics
  • Solid solutions of segnetoelectrics with different crystalline structure
  • Solid solutions of niobate segnetoelectrics
  • Glasscrystalline piezoelectrics

Main invention:

Totally: 97 authors' certificates of USSR, 1 patent of France

  • Piezoelectric ceramic material. Authors' certificate of USSR Nr. 1544754, 1990
  • Dielectric ceramic material. Authors' certificate of USSR Nr. 1527219, 1989
  • Electroconductive glass. Authors' certificate of USSR Nr. 1522674, 1989
  • Piezoelectric lead zirconate titanate ceramics. Patent of France 2219132, 1975

About the inventions

Piezoelectric ceramics is a material causing piezoelectric effect, e.g. it can convert electric energy into mechanical and vice versa. Creation of piezoelectrics of practical importance by performing polycristallyne processing of material is closely connected with problems of segnetoelectricity. In 1945 scientists discovered segnetoelectric properties of barium titanate BaTiO3. That encouraged the studies of segnetoelectricity. By polarizing the samples of BaTiO3 segnetoelectric ceramics in the field of direct stress they can be used as piezoelectric elements. Unlike segneto salt BaTiO3 ceramics doesn't dissolve in water. It possesses high water and heat resistance and it can be shaped in any desirable form. As a piezoelectric material segnetoceramics began to be widely used after the appearance of PZT (plumbum-zirconium-titanate) ceramics. This ceramics comprises the solid solution of lead titanate PbTiO3 (Tc =500° C) and antisegnetoelectric lead zirconate PbZr O3 (Tc =234° C). Pb( Zr0,55 Ti0,45)O3 must be marked as a composition of ceramics with especially extensive application.

More about the inventor (in Latvian)

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