Fabrication and properties of low temperature sintered PZT-PMN films

Abstract

A film of PZT-PMN composition was fabricated by the deposition of fine powder entrained in airflow on to a substrate at the temperature of 20 °C. The particle flow generated by a jet mill desintegrator circulated inside the cylindrical substrate tube producing a build up on the internal surface of the cylinder. The resulting film, 70 – 150 µm thick was mechanically removed (delaminated) from the substrate and sintered at 800 °C. Microscopic examination of the green and sintered films revealed a very dense microstructure with a grain size for the sintered film of 0.2 – 0.8 µm. The relative permittivity at 1 kHz was about 100 before sintering and 2000 after sintering (unpoled). The permittivity of the sintered film had the same value as for bulk ceramic samples fabricated from the same powder using conventional isostatic pressing technique and sintered at 1250 °C to 97 % of the theoretical density.The study showed that the properties of the green body produced by the powder deposition process were superior to the properties of bulk samples prepared by the conventional pressing procedure. The method provides a route for the formation of a fine grain microstructure, and a sintering temperature 450 °C lower than the accepted sintering temperature for this PZT-PMN composition.

Morphology of PZT-PMN Films Grown from Airflow

“…As it was reported previously [3], high density AFD PZT-PMN ceramics have been processed at much lower temperatures than the standard sintering temperature 1250 • C. Although sintering of films at low temperatures required longer time, the resultant density and dielectric properties were superior to bulk ceramics sintered using conventional processing techniques. The relative density of as-deposited PZT-PMN films was found to be close to 80% of theoretical, thereby exceeding the green density of isostatically pressed bulk samples (63-67% th.).…”

“…In conventional techniques processing temperatures in excess of 1000 • C are needed to sinter acceptably dense ceramics and multilayered structures. A recently proposed method to grow PZT ceramic films from air-flow [3] offers a novel route to fabricate films with fine grained microstructures at temperatures 450 • C lower than in standard ceramic processes. In this paper we report on morphology and microstructure of PZT-PMN films which, we believe, is responsible for the unusual properties of airflow deposited (AFD) ferroelectrics.…”

Properties of compositionally graded Ba(1−x)SrxTiO3 self-standing thick films

“…8 The airflow was generated by a commercial jet-mill (Micron Master 02-506) fed from a compressed air line at a pressure of 700 kPa. The graded thick films were created by sequentially depositing five layers with different compositions on nickel substrate at room temperature.…”

Switching Ba(1 −x)SrxTiO3Structures in the Vicinity of the Curie Point

“…Then the powders were dried and calcined at 1150 • C for 5 hours. The technique of thick film deposition from airflow has been described in detail elsewhere [7]. The airflow was generated by a commercial jet-mill (Micron Master 02-506) fed from a compressed air line at a pressure of 700 kPa.…”