Journal Home > Volume 11 , issue 9

A green body with a density as high as possible is critical to diminish the crisis of deformation or cracking when large-size parts are sintered. Here, a new method, i.e., re-fluidising the aged ceramic gel is developed to prepare the high-density green body. Alumina slurry with 56 vol% solid loading and copolymers of isobutylene and maleic anhydride were aged without vaporisation and re-fluidised by non-intrusive shearing after removing the exuded water. The re-fluidised slurry was re-casted. The resultant wet gel was dried and deboned at a low temperature. The relative density of the obtained green body was 64.6%, 1.5% higher than that without aging and re-fluidising. The linear sintering shrinkage of the body decreased by 0.7%. The enhanced green density is explained from the viewpoint of the solid loading and the structure of the slurry.


menu
Abstract
Full text
Outline
About this article

Re-fluidising the aged gel for high-density alumina green body

Show Author's information Xiaolang WUa,bJin ZHAOa,b( )Shunzo SHIMAIaXiaojian MAOa,bJian ZHANGa,bShiwei WANGa,b( )
State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 200050, China
Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China

Abstract

A green body with a density as high as possible is critical to diminish the crisis of deformation or cracking when large-size parts are sintered. Here, a new method, i.e., re-fluidising the aged ceramic gel is developed to prepare the high-density green body. Alumina slurry with 56 vol% solid loading and copolymers of isobutylene and maleic anhydride were aged without vaporisation and re-fluidised by non-intrusive shearing after removing the exuded water. The re-fluidised slurry was re-casted. The resultant wet gel was dried and deboned at a low temperature. The relative density of the obtained green body was 64.6%, 1.5% higher than that without aging and re-fluidising. The linear sintering shrinkage of the body decreased by 0.7%. The enhanced green density is explained from the viewpoint of the solid loading and the structure of the slurry.

Keywords:

high density, green body, re-fluidising, alumina, colloid formation
Received: 09 March 2022 Revised: 13 May 2022 Accepted: 20 May 2022 Published: 21 July 2022 Issue date: September 2022
References(24)
[1]
Leo S, Tallon C, Stone N, et al. Near-net-shaping methods for ceramic elements of (body) armor systems. J Am Ceram Soc 2014, 97: 3013–3033.
[2]
Yang Y, Shimai S, Wang SW. Room-temperature gelcasting of alumina with a water-soluble copolymer. J Mater Res 2013, 28: 1512–1516.
[3]
Chen H, Shimai S, Zhao J, et al. Hydrophobic coagulation of alumina slurries. J Am Ceram Soc 2021, 104: 284–293.
[4]
Chen H, Zhao J, Shimai S, et al. High transmittance and grain-orientated alumina ceramics fabricated by adding fine template particles. J Adv Ceram 2022, 11: 582–588.
[5]
Qin XP, Zhou GH, Yang Y, et al. Gelcasting of transparent YAG ceramics by a new gelling system. Ceram Int 2014, 40: 12745–12750.
[6]
Zhang PP, Liu P, Sun Y, et al. Aqueous gelcasting of the transparent MgAl2O4 spinel ceramics. J Alloys Compd 2015, 646: 833–836.
[7]
Sun Y, Shimai S, Peng X, et al. Fabrication of transparent Y2O3 ceramics via aqueous gelcasting. Ceram Int 2014, 40: 8841–8845.
[8]
Wang J, Zhang F, Chen F, et al. Fabrication of aluminum oxynitride (γ-AlON) transparent ceramics with modified gelcasting. J Am Ceram Soc 2014, 97: 1353–1355.
[9]
Wang LY, An LQ, Zhao J, et al. High-strength porous alumina ceramics prepared from stable wet foams. J Adv Ceram 2021, 10: 852–859.
[10]
Ren JT, Ying W, Zhao J, et al. High-strength porous mullite ceramics fabricated from particle-stabilized foams via oppositely charged dispersants and surfactants. Ceram Int 2019, 45: 6385–6391.
[11]
Di ZX, Shimai S, Zhao J, et al. Dewatering of spontaneous-coagulation-cast alumina ceramic gel by filtrating with low pressure. Ceram Int 2019, 45: 12789–12794.
[12]
Sun Y, Shimai S, Peng X, et al. A method for gelcasting high-strength alumina ceramics with low shrinkage. J Mater Res 2014, 29: 247–251.
[13]
Mao XJ, Chen H, Zhao J, et al. Spontaneous coagulation casting: History and its development. Adv Ceram 2019, 40: 398–416. (in Chinese)
[14]
Lu YJ, Gan K, Huo WL, et al. Dispersion and gelation behavior of alumina suspensions with Isobam. Ceram Int 2018, 44: 11357–11363.
[15]
Marsico CA, Orlicki JA, Blair VL. Investigation of room-temperature super-stabilized suspension casting system mechanism. J Am Ceram Soc 2020, 103: 1514–1519.
[16]
Carretti E, Dei L, Weiss RG. Soft matter and art conservation. Rheoreversible gel and beyond. Soft Matter 2005, 1: 17–22.
[17]
Balzer B, Hruschka MKM, Gauckler LJ. Coagulation kinetics and mechanical behavior of wet alumina green bodies produced via DCC. J Colloid Interface Sci 1999, 216: 379–386.
[18]
Peng X, Shimai S, Sun Y, et al. Wet green-state joining of alumina ceramics without paste. J Am Ceram Soc 2015, 98: 2728–2731.
[19]
Tarı̀ G, Ferreira JMF. Influence of solid loading on drying-shrinkage behaviour of slip cast bodies. J Eur Ceram Soc 1998, 18: 487–493.
[20]
Maleksaeedi S, Paydar MH, Ma J. Centrifugal gel casting: A combined process for the consolidation of homogenous and reliable ceramics. J Am Ceram Soc 2010, 93: 413–419.
[21]
Alex TC, Kumar R, Roy SK, et al. Mechanically induced reactivity of gibbsite: Part 1. Planetary milling. Powder Technol 2014, 264: 105–113.
[22]
Alex TC, Kumar R, Roy SK, et al. Mechanically induced reactivity of gibbsite: Part 2. Attrition milling. Powder Technol 2014, 264: 229–235.
[23]
Krell A, Blank P, Ma HW, et al. Processing of high-density submicrometer Al2O3 for new applications. J Am Ceram Soc 2003, 86: 546–553.
[24]
Zheng JM, Reed JS. Effects of particle packing characteristics on solid-state sintering. J Am Ceram Soc 1989, 72: 810–817.
Publication history
Copyright
Acknowledgements
Rights and permissions

Publication history

Received: 09 March 2022
Revised: 13 May 2022
Accepted: 20 May 2022
Published: 21 July 2022
Issue date: September 2022

Copyright

© The Author(s) 2022.

Acknowledgements

This work was supported by the National Natural Science Foundation of China (No. 52130207).

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made.

The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.

To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.

Reprints and Permission requests may be sought directly from editorial office.

Return