The aim of the present research is to provide a technique for preparing open-cell Al2O3-ZrO2 ceramic foams with uniform cell size.This technique used plant seeds to array templates and centrifugal slip casting to obta...The aim of the present research is to provide a technique for preparing open-cell Al2O3-ZrO2 ceramic foams with uniform cell size.This technique used plant seeds to array templates and centrifugal slip casting to obtain cell struts with high packing density.Aqueous Al2O3-ZrO2 slurries with up to 50 vol.% solid contents were prepared and the rheological characteristic of the slurries was investigated.Consolidation was performed at an acceleration of 2,860 g for 60 min.The effect of the characteristic of plant seeds on the drying behavior of Al2O3-ZrO2 green compact was analyzed.The effects of the solid contents of slurries on segregation phenomena of Al2O3 and ZrO2 particles and green compact uniformity were investigated.The compressive stress-strain curve and deformation behavior of Al2O3-ZrO2 ceramic foams prepared using plant seed template were analyzed.The results showed segregation phenomenon is negligible for highly stable slurry with 50 vol.% solid loading.The prepared cell struts of Al2O3-ZrO2 foams have high green density (61.9% TD), sintered density (99.1% TD) and homogeneous microstructure.When sintered at 1,550 ℃ for 2 h, the cell size of Al2O3-ZrO2 foam is approximately uniform and the diameter is about 1.1 mm.The porosity and compressive strength of sintered products is 66.2% and 5.86 MPa, respectively.展开更多
Polymeric sponge replication method is one of the common ways for ceramic foam production. The existence of central triangular voids in the struts results in a decrease of mechanical properties limiting their applicat...Polymeric sponge replication method is one of the common ways for ceramic foam production. The existence of central triangular voids in the struts results in a decrease of mechanical properties limiting their applications. To remove this defect, some additives consisting of Al powder particles and silica sol are added to ceramic slurries consisting of Al2O3 and ZrO2 （partially stabilized zirconia）. With increasing temperature for pyrolyzing and sintering of raw materials, first the Al powder and then the glass phase which consisted of melted Al2O3, ZrO2 and SiO2 was soaked into hollow struts. SEM investigations showed that the center of foam struts were free of hollows. XRD considerations depicted that a ZrO2 phase with tetragonal crystallographic structure is present in the produced foam which could be the reason of improved toughness and mechanical properties. Compressive strength of foams increased significantly due to the decrease of closed porosity. The Weibull statistical study showed remarkable increasing of the Weibull module and its value for foams with 10, 20 and 30 ppi was 5.91, 6.06 and 6.53 respectively.展开更多
基金supported by the National Natural Science Foundation of China (50672014)Innovation Research Team Program of the Ministry of Education (IRT0713)
文摘The aim of the present research is to provide a technique for preparing open-cell Al2O3-ZrO2 ceramic foams with uniform cell size.This technique used plant seeds to array templates and centrifugal slip casting to obtain cell struts with high packing density.Aqueous Al2O3-ZrO2 slurries with up to 50 vol.% solid contents were prepared and the rheological characteristic of the slurries was investigated.Consolidation was performed at an acceleration of 2,860 g for 60 min.The effect of the characteristic of plant seeds on the drying behavior of Al2O3-ZrO2 green compact was analyzed.The effects of the solid contents of slurries on segregation phenomena of Al2O3 and ZrO2 particles and green compact uniformity were investigated.The compressive stress-strain curve and deformation behavior of Al2O3-ZrO2 ceramic foams prepared using plant seed template were analyzed.The results showed segregation phenomenon is negligible for highly stable slurry with 50 vol.% solid loading.The prepared cell struts of Al2O3-ZrO2 foams have high green density (61.9% TD), sintered density (99.1% TD) and homogeneous microstructure.When sintered at 1,550 ℃ for 2 h, the cell size of Al2O3-ZrO2 foam is approximately uniform and the diameter is about 1.1 mm.The porosity and compressive strength of sintered products is 66.2% and 5.86 MPa, respectively.
文摘Polymeric sponge replication method is one of the common ways for ceramic foam production. The existence of central triangular voids in the struts results in a decrease of mechanical properties limiting their applications. To remove this defect, some additives consisting of Al powder particles and silica sol are added to ceramic slurries consisting of Al2O3 and ZrO2 （partially stabilized zirconia）. With increasing temperature for pyrolyzing and sintering of raw materials, first the Al powder and then the glass phase which consisted of melted Al2O3, ZrO2 and SiO2 was soaked into hollow struts. SEM investigations showed that the center of foam struts were free of hollows. XRD considerations depicted that a ZrO2 phase with tetragonal crystallographic structure is present in the produced foam which could be the reason of improved toughness and mechanical properties. Compressive strength of foams increased significantly due to the decrease of closed porosity. The Weibull statistical study showed remarkable increasing of the Weibull module and its value for foams with 10, 20 and 30 ppi was 5.91, 6.06 and 6.53 respectively.
