The CaO doped 10NiO-NiFe2O4 composite ceramics were prepared by the cold isostatic pressing-sintering process, and the effects of CaO content on the phase composition, mechanical property and thermal shock resistance ...The CaO doped 10NiO-NiFe2O4 composite ceramics were prepared by the cold isostatic pressing-sintering process, and the effects of CaO content on the phase composition, mechanical property and thermal shock resistance of 10NiO-NiFe2O4 composite ceramics were studied. The results show that the samples mainly consist of NiO and NiFe2O4 when content of CaO is less than 4%(mass fraction), bending strength increases obviously by CaO doping. Bending strength of the samples doped with 2% CaO is above 185 MPa, but that of the samples without CaO is only 60 MPa. Fracture toughness is improved obviously by CaO doping, the samples doped with 2% CaO have the maximum fracture toughness of 2.12 MPa ·m1/2 , which is about two times of that of the undoped ceramics. CaO doping is bad to thermal shock resistance of 10NiO-NiFe2O4 composite ceramics.展开更多
xNi/10NiO-NiFe2O4 （x=5, 10, 17） cermets and those doped with 1% BaO （mass fraction） were prepared by cold isostatic pressing at 200 MPa and sintering in nitrogen atmosphere at 1 473 K. The effects of BaO addition ...xNi/10NiO-NiFe2O4 （x=5, 10, 17） cermets and those doped with 1% BaO （mass fraction） were prepared by cold isostatic pressing at 200 MPa and sintering in nitrogen atmosphere at 1 473 K. The effects of BaO addition on relative density, microstructure and electric conductivity of cermets were investigated. The results show that relative densities ofxNi/10NiO-NiFe2O4 cermets （x=5, 10, 17） doped with 1% BaO at 1 473 K in nitrogen atmosphere are increased by 0.49%, 1.45% and 2.99% compared with those of the undoped BaO cermets, respectively. Moreover, the electric conductivities （21.98, 28.37 and 50.10 S/cm） of xNi/10NiO-NiFe2O4 cermets （x=5, 10, 17） doped with 1% BaO at 1 233 K are improved compared with those （18.70, 22.79 and 39.58 S/cm） of xNi/lONiO-NiFe2O4 cermets （x=5, 10, 17）, respectively. This indicates that perhaps the addition of BaO or formation of BaFe204 and Ba2Fe2O5 has an active effect on electric conductivities ofxNi/10NiO-NiFe2O4 （x=5, 10, 17） cermets.展开更多
基金Project(2005CB623703) supported by the National Basic Research Program of China
文摘The CaO doped 10NiO-NiFe2O4 composite ceramics were prepared by the cold isostatic pressing-sintering process, and the effects of CaO content on the phase composition, mechanical property and thermal shock resistance of 10NiO-NiFe2O4 composite ceramics were studied. The results show that the samples mainly consist of NiO and NiFe2O4 when content of CaO is less than 4%(mass fraction), bending strength increases obviously by CaO doping. Bending strength of the samples doped with 2% CaO is above 185 MPa, but that of the samples without CaO is only 60 MPa. Fracture toughness is improved obviously by CaO doping, the samples doped with 2% CaO have the maximum fracture toughness of 2.12 MPa ·m1/2 , which is about two times of that of the undoped ceramics. CaO doping is bad to thermal shock resistance of 10NiO-NiFe2O4 composite ceramics.
基金Project(2005CB623703) supported by the National Basic Research Program of ChinaProject(50721003) supported by the National Natural Science Fund for Innovation Group of ChinaProject(2008AA030501) supported by the National High-Tech Research and Development Program of China
文摘xNi/10NiO-NiFe2O4 （x=5, 10, 17） cermets and those doped with 1% BaO （mass fraction） were prepared by cold isostatic pressing at 200 MPa and sintering in nitrogen atmosphere at 1 473 K. The effects of BaO addition on relative density, microstructure and electric conductivity of cermets were investigated. The results show that relative densities ofxNi/10NiO-NiFe2O4 cermets （x=5, 10, 17） doped with 1% BaO at 1 473 K in nitrogen atmosphere are increased by 0.49%, 1.45% and 2.99% compared with those of the undoped BaO cermets, respectively. Moreover, the electric conductivities （21.98, 28.37 and 50.10 S/cm） of xNi/10NiO-NiFe2O4 cermets （x=5, 10, 17） doped with 1% BaO at 1 233 K are improved compared with those （18.70, 22.79 and 39.58 S/cm） of xNi/lONiO-NiFe2O4 cermets （x=5, 10, 17）, respectively. This indicates that perhaps the addition of BaO or formation of BaFe204 and Ba2Fe2O5 has an active effect on electric conductivities ofxNi/10NiO-NiFe2O4 （x=5, 10, 17） cermets.
