Microwave-assisted debinding of Al2O3 parts printed by stereolithography

Complex shapes pieces of Al2O3 can be rapidly shaped by SLA technology. However, debinding and sintering post-shaping steps still involve long working times. Sintering by microwave has been previously studied providing important time-saving in the fabrication processes and finer microstructures. However, debinding processes are still carried out by conventional methods which compromise the time-saving expectative. In this work, microwave debinding has been evaluated. Conventional and microwave debinding were carried out over pieces of Al2O3 shaped by SLA. The thermal cycle for microwave debinding has been optimized according to the organic species' thermal oxidation process limitations. In both cases, thermal treatments for sintering have been ended by conventional and microwave methods. The relative density, microstructure, hardness and Young modulus were measured and analyzed. Samples sintered by different methods show differences in these properties due to the different temperatures that can be reached with the available experimental devices. However, no significant differences are found in any of those properties for samples treated with different debinding methods but after the same sintering process. For example, relative densities of 96% are achieved for conventionally sintered samples even if they were previously treated by conventional or microwave debinding. In such cases, hardness value was 20 ± 7 and 19 ± 2 GPa respectively and the Young Modulus value was 306 ± 113 and 335 ± 71 GPa respectively. According to these results, the microwave is a feasible method for debinding process.