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Title: Yttrium. alpha. -sialon ceramics by hot isostatic pressing and post-hot isostatic pressing

Abstract

This paper reports on dense {alpha}-sialon materials that were produced by hot isostatic pressing (HIP) and post-hot isostatic pressing (post-HIP) using composition with the formula Y{sub x}(Si{sub 12{minus}4.5x}), Al{sub 4.5x}-O{sub 1.5x},N{sub 16{minus}1.5x} with 0.1 {le} x {le} 0.9 and with the same compositions with extra additions of yttria and aluminum nitride. X-ray diffraction analyses show how the phase content changes from large amounts of {beta}-sialon (x = 0.1) to large amounts of {alpha}-sialon (x = 0.4) and increasing amounts of mellilite and sialon polytypoids (x = 0.8). Samples HIPed at 1600{degrees}C for 2 h contained unreacted {alpha}-silicon nitride, while those HIPed at 1750{degrees}C for 1 h did not. This could be due to the fact that the time is too short to achieve equilibrium or that the high pressure (200 MPa) prohibits {alpha}-sialon formation. Sintering at atmospheric pressure leads to open porosity for all compositions except those with excess yttria. Therefore, only samples with excess yttria were post-HIPed. Microstructural analyses showed that the post-HIPed samples had the highest {alpha}-sialon content.

Authors:
;  [1];  [2];  [3]
  1. Dept. of Engineering Materials, Lulea Univ. of Technology, S-951 Lulea (SE)
  2. AB Sandvik Hard Materials, S-126 80 Stockholm (SE)
  3. School of Materials Science and Engineering, University of New South Wales, Kensington, NSW 2033 (AU)
Publication Date:
OSTI Identifier:
5332540
Resource Type:
Journal Article
Journal Name:
Journal of the American Ceramic Society; (United States)
Additional Journal Information:
Journal Volume: 75:2; Journal ID: ISSN 0002-7820
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CERAMICS; CHEMICAL COMPOSITION; PHASE TRANSFORMATIONS; YTTRIUM COMPOUNDS; HARDNESS; HOT PRESSING; X-RAY DIFFRACTION; ADDITIVES; ALUMINIUM NITRIDES; EQUILIBRIUM; HIGH PRESSURE; MICROSTRUCTURE; SINTERING; ALUMINIUM COMPOUNDS; COHERENT SCATTERING; CRYSTAL STRUCTURE; DIFFRACTION; FABRICATION; MATERIALS WORKING; MECHANICAL PROPERTIES; NITRIDES; NITROGEN COMPOUNDS; PNICTIDES; PRESSING; SCATTERING; TRANSITION ELEMENT COMPOUNDS; 360202* - Ceramics, Cermets, & Refractories- Structure & Phase Studies; 360203 - Ceramics, Cermets, & Refractories- Mechanical Properties; 360201 - Ceramics, Cermets, & Refractories- Preparation & Fabrication

Citation Formats

Bartek, A, Johansson, T, Ekstrom, T, and Herbertsson, H. Yttrium. alpha. -sialon ceramics by hot isostatic pressing and post-hot isostatic pressing. United States: N. p., 1992. Web. doi:10.1111/j.1151-2916.1992.tb08198.x.
Bartek, A, Johansson, T, Ekstrom, T, & Herbertsson, H. Yttrium. alpha. -sialon ceramics by hot isostatic pressing and post-hot isostatic pressing. United States. https://doi.org/10.1111/j.1151-2916.1992.tb08198.x
Bartek, A, Johansson, T, Ekstrom, T, and Herbertsson, H. 1992. "Yttrium. alpha. -sialon ceramics by hot isostatic pressing and post-hot isostatic pressing". United States. https://doi.org/10.1111/j.1151-2916.1992.tb08198.x.
@article{osti_5332540,
title = {Yttrium. alpha. -sialon ceramics by hot isostatic pressing and post-hot isostatic pressing},
author = {Bartek, A and Johansson, T and Ekstrom, T and Herbertsson, H},
abstractNote = {This paper reports on dense {alpha}-sialon materials that were produced by hot isostatic pressing (HIP) and post-hot isostatic pressing (post-HIP) using composition with the formula Y{sub x}(Si{sub 12{minus}4.5x}), Al{sub 4.5x}-O{sub 1.5x},N{sub 16{minus}1.5x} with 0.1 {le} x {le} 0.9 and with the same compositions with extra additions of yttria and aluminum nitride. X-ray diffraction analyses show how the phase content changes from large amounts of {beta}-sialon (x = 0.1) to large amounts of {alpha}-sialon (x = 0.4) and increasing amounts of mellilite and sialon polytypoids (x = 0.8). Samples HIPed at 1600{degrees}C for 2 h contained unreacted {alpha}-silicon nitride, while those HIPed at 1750{degrees}C for 1 h did not. This could be due to the fact that the time is too short to achieve equilibrium or that the high pressure (200 MPa) prohibits {alpha}-sialon formation. Sintering at atmospheric pressure leads to open porosity for all compositions except those with excess yttria. Therefore, only samples with excess yttria were post-HIPed. Microstructural analyses showed that the post-HIPed samples had the highest {alpha}-sialon content.},
doi = {10.1111/j.1151-2916.1992.tb08198.x},
url = {https://www.osti.gov/biblio/5332540}, journal = {Journal of the American Ceramic Society; (United States)},
issn = {0002-7820},
number = ,
volume = 75:2,
place = {United States},
year = {1992},
month = {2}
}