Plastic forming and microstructural development of x-alumina ceramics from highly compacted green bodies using extrusion

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@article{8f6f501d041442819906b092e878e3ce,
title = "Plastic forming and microstructural development of x-alumina ceramics from highly compacted green bodies using extrusion",
abstract = "High density (> 99% TD) and microstructurally controlled alpha-alumina ceramics were produced from seeded nano-size boehmite (gamma-AlOOH) sols with a very fine crystallite size (2-3 nm). A totally wet processing technique comprising vacuum filtering and pressure filtration (PF) was applied in order to increase the solids-loading of the sol and hence form an extrudable paste suitable for plastic forming using extrusion. High packing densities (> 68% TD in the green state) are achieved by PF starting from the slurry state resulting in the formation of a consolidated paste which is further consolidated by extrusion. This combined processing technique was successfully applied, in an attempt to reduce the gamma-Al2O3 formation temperature, and hence lower the theta- to alpha-Al2O3 transition temperature. The microstructure of dense alpha-Al2O3 bodies derived from seeded boehmite sol contains very fine (250 nm) alumina grains after sintering at 1200 degreesC for 2 h. Although the DTA evidence points to a theta- to alpha-Al2O3 transition temperature of 1208 degreesC for a seeded (with 30 mn TiO2) sample, X-ray analysis indicates that a seeded, pressure filtrated and extruded sample is transformed to alpha-Al2O3 phase after sintering at 1100 degreesC for 2 h. (C), 2002 Elsevier Science Ltd. All rights reserved.",
keywords = "sol-gel processes, seeding, pressure filtration, microstructure, extrusion, Al2O3, AlOOH",
author = "Cengiz Kaya and Edwin Butler",
year = "2002",
month = jan,
day = "1",
doi = "10.1016/S0955-2219(01)00523-4",
language = "English",
volume = "22",
pages = "1917--1926",
journal = "Journal of the European Ceramic Society",
issn = "0955-2219",
publisher = "Elsevier",
number = "2002",

}

RIS

TY - JOUR

T1 - Plastic forming and microstructural development of x-alumina ceramics from highly compacted green bodies using extrusion

AU - Kaya, Cengiz

AU - Butler, Edwin

PY - 2002/1/1

Y1 - 2002/1/1

N2 - High density (> 99% TD) and microstructurally controlled alpha-alumina ceramics were produced from seeded nano-size boehmite (gamma-AlOOH) sols with a very fine crystallite size (2-3 nm). A totally wet processing technique comprising vacuum filtering and pressure filtration (PF) was applied in order to increase the solids-loading of the sol and hence form an extrudable paste suitable for plastic forming using extrusion. High packing densities (> 68% TD in the green state) are achieved by PF starting from the slurry state resulting in the formation of a consolidated paste which is further consolidated by extrusion. This combined processing technique was successfully applied, in an attempt to reduce the gamma-Al2O3 formation temperature, and hence lower the theta- to alpha-Al2O3 transition temperature. The microstructure of dense alpha-Al2O3 bodies derived from seeded boehmite sol contains very fine (250 nm) alumina grains after sintering at 1200 degreesC for 2 h. Although the DTA evidence points to a theta- to alpha-Al2O3 transition temperature of 1208 degreesC for a seeded (with 30 mn TiO2) sample, X-ray analysis indicates that a seeded, pressure filtrated and extruded sample is transformed to alpha-Al2O3 phase after sintering at 1100 degreesC for 2 h. (C), 2002 Elsevier Science Ltd. All rights reserved.

AB - High density (> 99% TD) and microstructurally controlled alpha-alumina ceramics were produced from seeded nano-size boehmite (gamma-AlOOH) sols with a very fine crystallite size (2-3 nm). A totally wet processing technique comprising vacuum filtering and pressure filtration (PF) was applied in order to increase the solids-loading of the sol and hence form an extrudable paste suitable for plastic forming using extrusion. High packing densities (> 68% TD in the green state) are achieved by PF starting from the slurry state resulting in the formation of a consolidated paste which is further consolidated by extrusion. This combined processing technique was successfully applied, in an attempt to reduce the gamma-Al2O3 formation temperature, and hence lower the theta- to alpha-Al2O3 transition temperature. The microstructure of dense alpha-Al2O3 bodies derived from seeded boehmite sol contains very fine (250 nm) alumina grains after sintering at 1200 degreesC for 2 h. Although the DTA evidence points to a theta- to alpha-Al2O3 transition temperature of 1208 degreesC for a seeded (with 30 mn TiO2) sample, X-ray analysis indicates that a seeded, pressure filtrated and extruded sample is transformed to alpha-Al2O3 phase after sintering at 1100 degreesC for 2 h. (C), 2002 Elsevier Science Ltd. All rights reserved.

KW - sol-gel processes

KW - seeding

KW - pressure filtration

KW - microstructure

KW - extrusion

KW - Al2O3

KW - AlOOH

UR - http://www.scopus.com/inward/record.url?scp=0036833037&partnerID=8YFLogxK

U2 - 10.1016/S0955-2219(01)00523-4

DO - 10.1016/S0955-2219(01)00523-4

M3 - Article

VL - 22

SP - 1917

EP - 1926

JO - Journal of the European Ceramic Society

JF - Journal of the European Ceramic Society

SN - 0955-2219

IS - 2002

ER -