Additive manufacturing of ZrO2-Al2O3 ceramic components by selective laser melting

Purpose - The purpose this paper is to develop an additive manufacturing (AM) technique for high-strength oxide ceramics. The process development aims at directly manufacturing fully dense ceramic freeform-components with good mechanical properties. Design/methodology/approach - The selective laser melting of the ceramic materials zirconia and alumina has been investigated experimentally. The approach followed up is to completely melt ZrO2/Al2O3 powder mixtures by a focused laser beam. In order to reduce thermally induced stresses, the ceramic is preheated to a temperature of at least 1,600 degrees C during the build up process. Findings - It is possible to manufacture ceramic objects with almost 100 percent density, without any sintering processes or any post-processing. Crack-free specimens have been manufactured that have a flexural strength of more than 500 MPa. Manufactured objects have a fine-grained two-phase microstructure consisting of tetragonal zirconia and alpha-alumina. Research limitations/implications - Future research may focus on improving the surface quality of manufactured components, solving issues related to the cold powder deposition on the preheated ceramic, further increasing the mechanical strength and transferring the technology from laboratory scale to industrial application. Practical implications - Potential applications of this technique include manufacturing individual all-ceramic dental restorations, ceramic prototypes and complex-shaped ceramic components that cannot be made by any other manufacturing technique. Originality/value - This new manufacturing technique based on melting and solidification of high-performance ceramic material has some significant advantages compared to laser sintering techniques or other manufacturing techniques relying on solid-state sintering processes.