As a non-toxic copolymer of isobutylene and maleic anhydride,Isobam is successfully used as a dispersant and a gelling agent for fabricating porous Si_(3)N_(4) ceramics by gel casting.The dispersity and rheological pr...As a non-toxic copolymer of isobutylene and maleic anhydride,Isobam is successfully used as a dispersant and a gelling agent for fabricating porous Si_(3)N_(4) ceramics by gel casting.The dispersity and rheological properties of the Si_(3)N_(4) slurry are influenced by the pH,milling time,and Isobam content which varies from 0.1 wt.%to 0.6 wt.%,and these factors are investigated.The slurry with 40 vol.%solid content and milled for 4 h has a high zeta potential at pH 12(adjusted by Tetramethyl ammonium hydroxide(TMAH)),which means that the particles are well dispersed.The mechanisms of TMAH are electrostatic repulsion and steric hindrance.The viscosity of the slurry increases with the increase of Isobam content.After pressureless sintering at 1700℃ for 2 h,a uniform unique interlocking microstructure of rod-like β-Si_(3)N_(4) grains is observed,which may improve the flexural strength of the ceramics by intergranular fracture and particle pullout of β-Si_(3)N_(4) grains.The density and porosity of the samples fluctuate negligibly with the increase of Isobam content,and the Si_(3)N_(4) ceramic with 0.1 wt.% Isobam exhibits the highest bending strength of 251.6 MPa among all samples.展开更多
基金Authors appreciate the financial supported by the Shandong Province Key Research and Development Plan(2020JMRH0401,Grant No.2019RKB01018)National Natural Science Foundation of China(Grant No.51872118)the Shandong Provincial Natural Science Foundation,(Grant No.ZR2018PEM008,ZR2019MEM055).
文摘As a non-toxic copolymer of isobutylene and maleic anhydride,Isobam is successfully used as a dispersant and a gelling agent for fabricating porous Si_(3)N_(4) ceramics by gel casting.The dispersity and rheological properties of the Si_(3)N_(4) slurry are influenced by the pH,milling time,and Isobam content which varies from 0.1 wt.%to 0.6 wt.%,and these factors are investigated.The slurry with 40 vol.%solid content and milled for 4 h has a high zeta potential at pH 12(adjusted by Tetramethyl ammonium hydroxide(TMAH)),which means that the particles are well dispersed.The mechanisms of TMAH are electrostatic repulsion and steric hindrance.The viscosity of the slurry increases with the increase of Isobam content.After pressureless sintering at 1700℃ for 2 h,a uniform unique interlocking microstructure of rod-like β-Si_(3)N_(4) grains is observed,which may improve the flexural strength of the ceramics by intergranular fracture and particle pullout of β-Si_(3)N_(4) grains.The density and porosity of the samples fluctuate negligibly with the increase of Isobam content,and the Si_(3)N_(4) ceramic with 0.1 wt.% Isobam exhibits the highest bending strength of 251.6 MPa among all samples.
