Effects of organic additives on microstructure and mechanical properties of porous Si3N4 ceramics

• Published in: Bulletin of materials science Vol. 33; no. 3; pp. 285 - 291
• Main Authors: Yu, Fangli, Wang, Huanrui, Yang, Jianfeng, Gao, Jiqiang
• Format: Journal Article
• Language: English
• Published: India Springer-Verlag 01.06.2010; Springer Nature B.V
• Subjects: Additives; Bend strength; Binder removal; Binders; Ceramics; Chemistry and Materials Science; Density; Engineering; Extrusion molding; Fracture toughness; Materials Science; Mechanical properties; Microstructure; Polyethylene glycol; Porosity; Silicon nitride; Sintering (powder metallurgy); Weibull modulus; ceramics; microstructure; porous Si; processing; Organic additives; Weibull distribution; mechanical properties; N
• ISSN: 0250-4707; 0973-7669
• DOI: 10.1007/s12034-010-0044-6

Green bodies of porous Si 3 N 4 ceramics were shaped by extrusion technique using different organic additives as binder during extrusion molding. Different porosity, microstructures and mechanical properties after the extrusion, drying, debinding and sintering stages were investigated. The solid slurry content of 70–75% and extrusion pressure of 0.5–1.0 MPa had played a decisive role in the smooth realization of extrusion molding. The porous Si 3 N 4 ceramics were obtained with excellent properties using 4% hydroxypropyl methyl cellulose (HPMC) as binder and polyethylene glycol (PEG) of molecular weight, 1000, as plasticizer with a density of 1.91 g cm −3 , porosity of 41.70%, three-point bending strength of 166.53 ± 20 MPa, fracture toughness of 2.45 ± 0.2 MPa m 1/2 and Weibull modulus (m) of 20.75.