LAUSR

Abstract We report the use of natural rubber as a binder for powder pressing for the first time. The feedstock for powder pressing is obtained by the co-coagulation of alumina powder-natural rubber latex co-dispersions in 10 mM formic acid solution. The pressing pressure and binder concentration are optimized by measuring the green density and diametrical compressive strength. The remarkable increase in diametrical compressive strength observed on heating the pressed bodies at 220 °C is due to the cross-linking of natural rubber. A maximum diametrical compressive strength of 9.4 MPa observed at 8 wt% natural rubber concentration is one of the highest values reported in the literature. The pressed compacts after cross-linking heat-treatment are amenable to milling, drilling and lathing using conventional machines and tools. The pressed bodies on binder removal and sintering at 1550 °C produce alumina ceramics of ~97% of theoretical density with an average grain size of 1.8 μm.