Improved Strength of Alumina Ceramic Gel and Green Body Based on Addition‐Esterification Reaction

Abstract

Ethylene glycol diglycidyl ether (EGDGE), a water‐soluble epoxy resin, was used as a complementary gelling agent to improve the strength of alumina green bodies gelcast using PIBM (a copolymer of isobutylene and maleic anhydride acting as both dispersant and gelling agent) gelling system. The effects of EGDGE on the gelling behavior of PIBM‐EGDGE aqueous solutions and alumina slurries, mechanical properties of the resultant alumina gels, green bodies, and sintered ceramics were evaluated. Gelation of both the solutions and the slurries was accelerated with the addition of EGDGE. The changes in storage modulus (G′) of the slurries during gelation were quite different from those of the solutions. With the addition of 0.6 wt% EGDGE, G′ of the gel from a slurry with 50 wt% solid loading and 0.3 wt% PIBM increased 63% (100 min of testing), and flexural strength of the resultant green body increased 167%. Such gels and green bodies are strong enough for subsequent processing. They resulted in presintered bodies with low porosity and sintered ceramics with high relative density and flexural strength.

Effect of calcination temperature on friction and wear behavior of α–alumina (α‐Al2O3) for biomedical applications

“…As can be seen, the position of the maximum peaks in the patterns of alumina as a function of calcination temperature is similar. But with an increase in calcination temperature the intensity of diffraction peaks decreases while their width increases progressively as a result of the crystallite size refinement, micro‐strain and its origin . With increasing the temperature of calcination the brittle particles (Al 2 O 3 ) are uniformly dispersed.…”

Improved green strength of ceramic bodies through extrusion using hydroxypropyl methylcellulose as binder

“…In the production of ceramic parts, high green strength is desirable, because ceramic green bodies are usually handled and machined before sintering, and insufficient green strength may lead to the damage to green bodies . To date, intensive researches have been conducted to study the effects of different processing parameters such as primary particle and aggregate sizes, binder, lubricant and moisture on green strength of dry‐pressed ceramic green products .…”

“…To date, intensive researches have been conducted to study the effects of different processing parameters such as primary particle and aggregate sizes, binder, lubricant and moisture on green strength of dry‐pressed ceramic green products . In recent years, gelcasting as a relatively novel shaping method has also gained increasing attention in part due to its high green strength obtained . As an example, He et al recently used aqueous gelcasting based on double gel network system to fabricate ZrB 2 –SiC green ceramics with a green strength of 98.6 MPa …”