The conditions of ZnO-Al2O3 aqueous suspensions and slip casting were optimized to obtain dense green compacts and further to obtain high density ZnO-Al2O3 ceramic composites.The Zeta potential of raw powders was meas...The conditions of ZnO-Al2O3 aqueous suspensions and slip casting were optimized to obtain dense green compacts and further to obtain high density ZnO-Al2O3 ceramic composites.The Zeta potential of raw powders was measured.ZnO and Al2O3 powders have lower Zeta potential than-45 mV commonly at pH 8-10.3 with polyacrylic acid(PAA)added.The influence of pH and the mass fraction of the additives on the stability and fluidity of the suspensions added with PAA and polyethylene glycol(PEG) was investigated by experiments of viscosity and sedimentation.The suspensions have the lowest viscosity and the best stability at pH 9 with 0.2%PAA(mass fraction).The maximum density of green compacts is 66.6%of theoretical density(TD)with compacting and homogeneous green particles.An ultrahigh density sintered compact(>99.6%TD)could be obtained after pressureless sintering at 1 400℃for 2 h.展开更多
In the present study, a processing technique for recycling investment casting ceramic shell waste was proposed to separate valuable refractory aggregate zircon sand. The microstructure and phase constituents of the sh...In the present study, a processing technique for recycling investment casting ceramic shell waste was proposed to separate valuable refractory aggregate zircon sand. The microstructure and phase constituents of the shell waste and separation process were investigated. The results show that the characteristics of microstructure and phase constituents of the shell waste can meet the conditions for preferential y separating zircon sand, and zircon sand can be separated by gravity separation on a shaking table. The separated zircon sand has good shape and high purity, and can be used for the production of castings and other applications.展开更多
In this paper,based on three different kinds of ceramic side dams for thin strip antinuous casting,the friction and wearing property were studied.The effects of friction pressure,temperature and friction time on the f...In this paper,based on three different kinds of ceramic side dams for thin strip antinuous casting,the friction and wearing property were studied.The effects of friction pressure,temperature and friction time on the friction and wearing property of the ceramic side dam were researched.What’s more,the friction mechanism and wearing mechanism of the ceramic side dam were researched as well.Results show that the ceramic side dam of BN-SiA lO N has the best wearing resistance property.while at room temperature,16 min of friction time and0.35 MPa of friction pressure,the test friction coefficient is 0.60 and wearing capacity is 272.358 mm-3.In addition,when at 400℃,16 min of friction time and 0.18MPa of friction pressure,the test friction coefficient is0.70.The friction mechanism of ceramic side dam with the opposite wearing material is mainly the composite wear of adhesion,abrasive and fatigue.展开更多
Porous silica ceramics has been prepared with the starch consolidation casting method. Slurries with various fractions of starch added in were prepared by ball-milling. The evaluation of the microstructures was done t...Porous silica ceramics has been prepared with the starch consolidation casting method. Slurries with various fractions of starch added in were prepared by ball-milling. The evaluation of the microstructures was done through two techniques： Hg porosimetry and SEM investigation. The bending strength of the sintered samples varied within the range of 10 MPa-20 MPa and the low dielectric constant within the range of 2.0-2.4 correspondent with the porosity of 42%-56%. The ceramics holds a brilliant promise of being a kind of core material used in sandwich-like electromagnetic windows.展开更多
Sea urchin spines were chosen as a model system for biomimetic ceramics obtained using starch-blended slip casting. Porous alumina ceramics with cap-shaped layers with different alternating porosities were found to ha...Sea urchin spines were chosen as a model system for biomimetic ceramics obtained using starch-blended slip casting. Porous alumina ceramics with cap-shaped layers with different alternating porosities were found to have superior fracture behavior under bulk compression compared to ceramics with uniform porosity.They fail in a cascading manner,absorbing high amounts of energy during extended compression paths.The porosity variation in an otherwise single phase material mimicks the architectural microstructure design of sea urchin spines of Heterocentrotus mammillatus,which are promising model materials for impact protection.展开更多
基金Project(50477044)supported by the National Natural Science Foundation of China
文摘The conditions of ZnO-Al2O3 aqueous suspensions and slip casting were optimized to obtain dense green compacts and further to obtain high density ZnO-Al2O3 ceramic composites.The Zeta potential of raw powders was measured.ZnO and Al2O3 powders have lower Zeta potential than-45 mV commonly at pH 8-10.3 with polyacrylic acid(PAA)added.The influence of pH and the mass fraction of the additives on the stability and fluidity of the suspensions added with PAA and polyethylene glycol(PEG) was investigated by experiments of viscosity and sedimentation.The suspensions have the lowest viscosity and the best stability at pH 9 with 0.2%PAA(mass fraction).The maximum density of green compacts is 66.6%of theoretical density(TD)with compacting and homogeneous green particles.An ultrahigh density sintered compact(>99.6%TD)could be obtained after pressureless sintering at 1 400℃for 2 h.
文摘In the present study, a processing technique for recycling investment casting ceramic shell waste was proposed to separate valuable refractory aggregate zircon sand. The microstructure and phase constituents of the shell waste and separation process were investigated. The results show that the characteristics of microstructure and phase constituents of the shell waste can meet the conditions for preferential y separating zircon sand, and zircon sand can be separated by gravity separation on a shaking table. The separated zircon sand has good shape and high purity, and can be used for the production of castings and other applications.
文摘In this paper,based on three different kinds of ceramic side dams for thin strip antinuous casting,the friction and wearing property were studied.The effects of friction pressure,temperature and friction time on the friction and wearing property of the ceramic side dam were researched.What’s more,the friction mechanism and wearing mechanism of the ceramic side dam were researched as well.Results show that the ceramic side dam of BN-SiA lO N has the best wearing resistance property.while at room temperature,16 min of friction time and0.35 MPa of friction pressure,the test friction coefficient is 0.60 and wearing capacity is 272.358 mm-3.In addition,when at 400℃,16 min of friction time and 0.18MPa of friction pressure,the test friction coefficient is0.70.The friction mechanism of ceramic side dam with the opposite wearing material is mainly the composite wear of adhesion,abrasive and fatigue.
文摘Porous silica ceramics has been prepared with the starch consolidation casting method. Slurries with various fractions of starch added in were prepared by ball-milling. The evaluation of the microstructures was done through two techniques： Hg porosimetry and SEM investigation. The bending strength of the sintered samples varied within the range of 10 MPa-20 MPa and the low dielectric constant within the range of 2.0-2.4 correspondent with the porosity of 42%-56%. The ceramics holds a brilliant promise of being a kind of core material used in sandwich-like electromagnetic windows.
基金funded by European sources within the ERASMUS-SOCRATES program
文摘Sea urchin spines were chosen as a model system for biomimetic ceramics obtained using starch-blended slip casting. Porous alumina ceramics with cap-shaped layers with different alternating porosities were found to have superior fracture behavior under bulk compression compared to ceramics with uniform porosity.They fail in a cascading manner,absorbing high amounts of energy during extended compression paths.The porosity variation in an otherwise single phase material mimicks the architectural microstructure design of sea urchin spines of Heterocentrotus mammillatus,which are promising model materials for impact protection.
