PROPERTIES OF CERAMIC SUSPENSIONS FOR INJECTION-MOLDING BASED ON AGARBINDERS

A range of water based agar solutions were assessed as prospective bin ders for ceramic injection moulding. The effects of the agar content a nd the use of locust bean gum (LBG) on gel properties were investigate d. Glycerol was examined as a potential lubricant but no beneficial ef fects were observed. Some selected compositions were mixed with fine a lumina powder to make pastes for injection moulding. The tensile stren gth, fracture strain, and elastic modulus of the suspensions were meas ured at room temperature and the rheological behaviour was investigate d over a temperature range of 30-90-degrees-C. The addition of LBG inc reases the gel strength and fracture strain and as a result, LBG incre ases the fracture strength and the fracture strain of the paste. From the rheology of the paste, it was found that at lower temperatures the shear stress increases with the increase of shear rate. However, abov e 60-degrees-C, the shear stress is independent of shear rate.