Development of Bi-Layer Porosity Graded Ceramic Component
Porosity graded composite component can be found in applications such as fuel cells, filters or bio-scaffolds or implants. In this paper, two materials powder injection moulding is applied to manufacture bi-layer ceramic components with graded porosity. Ceramic spinel, AR7820, is selected to form the denser layer while the porous layer consists of AR7820 with starch or graphite pore former and spinel AR7845. The pore formers have proven to be feasible in producing porous structure in individual component. Porous layer with graphite and starch pore formers sintered at 1600oC has a porosity of 36% and 37% respectively. However delamination of the layers occurs when they are shaped together with AR7820. This is because the pore formers altered the shrinkage behaviour of the base material which resulted in discrepancies in the shrinkages between the two layers. On the other hand, defect free porosity graded composite component with good and continuous bonding between the layers was obtained when AR7845 is combined with AR7820.
Jianhong Zhao, Masanori Kunieda, Guilin Yang and Xue-Ming Yuan
Z. Y. A. Ong et al., "Development of Bi-Layer Porosity Graded Ceramic Component ", Key Engineering Materials, Vols. 447-448, pp. 376-380, 2010