FABRICATING SUCCESSFUL CERAMIC COMPONENTS USING DEVELOPMENT CARRIER SYSTEMS

摘要

Fabrication of complex ceramic components can be achieved through the process of Particle Injection Moulding (PIM). In this process a feedstock comprising of ceramic powders suspended in an organic carrier system (binder) is forced, at elevated temperatures, into preformed moulds. The organic binder is then thermally removed and the remaining powders are sintered to consolidate the ceramic. The carrier system is critical for developing the desired properties of the feedstock to enable flow and mould filling during injection and to sustain the integrity of the formed component during the subsequent firing process. This investigation describes the effect of three development carrier systems of high, medium and low viscosity, containing identical components but differing ratios, on component fabrication. The feedstock was optimised in solids loading and plasticiser additions. A PIM press was used for the moulding and before injection the feedstock was conditioned for both short and long mixing times. The process was characterised through rheometry, mechanical testing and interferometry. Experimental data illustrates that conditioning time and viscosity of the binder affects the surface roughness of components. Conditioning time also influences the flexural stress profile of the components under load. The ceramic strength properties using the low and medium viscosity binders were similar, however, a reduction in strength properties was observed when using the high viscosity binder.