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Strength of Green Ceramics with Low Binder Content
Author(s) -
Uhland Scott A.,
Holman Richard K.,
Morissette Sherry,
Cima Michael J.,
Sachs Emanuel M.
Publication year - 2001
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.2001.tb01098.x
Subject(s) - ceramic , materials science , composite material , toughness , adsorption , polymer , fabrication , flexural strength , adhesion , chemical engineering , chemistry , organic chemistry , medicine , alternative medicine , pathology , engineering
Acrylic‐based polymers are common binders that impart high green strength (>2 MPa) at low concentrations (<5.0 vol%). Strength at low binder concentrations may be determined by chemical bonding at the ceramic–polymer interface. We have studied the binding mechanisms as a function of ceramic surface chemistry using a cross‐linkable binder, which is based on a soluble poly(acrylic acid) (PAA, MW = 60 000) and glycerol. The cross‐linked PAA binder system has been integrated into a solid freeform fabrication process, which provides a means of fabricating very reproducible green bodies, including SiO 2 , TiO 2 , Al 2 O 3 , multicomponent oxides, and non‐oxides, with uniform density and composition. The ceramic parts contain only 2.5 vol% binder (solids basis), which increases the strength of the ceramic systems by at least a factor of 8 while the strength of Al 2 O 3 components increases by a factor of ∼24 (0.3 to 7.6 MPa). Addition of the binder improves the toughness of the ceramic bodies by an order of magnitude with SiO 2 representing the largest relative increase (2.8 × 10 −3 to 4.4 × 10 −2 MPa·m 1/2 ). The mechanical properties are dictated by two binding mechanisms: binder adsorption and mechanical interlocking. High green strengths result from adsorption of the binder onto the ceramic surface whereas toughness is enhanced by poor adhesion of the binder to the ceramic surface.