MoS2/γ－Al2O3 ceramic composite membrane is successfully synthesized by the sol-gel method based on the inorganic salt route. The aluminum hydrate sol derived from the inorganic salt Al(NO3)3, whose transparence and ...MoS2/γ－Al2O3 ceramic composite membrane is successfully synthesized by the sol-gel method based on the inorganic salt route. The aluminum hydrate sol derived from the inorganic salt Al(NO3)3, whose transparence and viscosity are 97% and 1.2 × 10-3 Pa. s, respectively, can be formed through adjusting the ratio of the peptizing agent H+ to Al3+ to 0.3. The aluminum hydrate gel at 110℃ is amorphous in structure and is heat-treated in air at 800℃ to form γ－Al2O3. The precursor derived from the mixture solution of ammonium molybdate, thioacetamide and a reducing agent, can be transformed into crystal MoS2 under reducing condition at 800℃. MoS2/γ－Al2O3 composite membrane is an organic whole and bps no gradation from MoS2 layer to γ－Al2O3 Iayer. The separation factor a H2/H2S through the MoS2/γ－Al2O3 composite membrane increase with rising temperature and a H2/H2S at 600℃ is 4.45 higher than the theoretical separation factor produced by the ideal Knudsen diffusion.展开更多
The effects of hot extrusion and addition of Al_(2)O_(3p) on both microstructure and tribological behavior of 7075 composites were investigated via optical microscopy(OM),scanning electron microscopy(SEM),energy dispe...The effects of hot extrusion and addition of Al_(2)O_(3p) on both microstructure and tribological behavior of 7075 composites were investigated via optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),and transmission electron microscopy(TEM).The experimental consequences reveal that the optimal addition of Al_(2)O_(3p) was 2 wt%.After hot extrusion,the Mg(Zn,Cu,Al)2 phases partially dissolve into the matrix and generate many uniformly distributed aging precipitation particles,the Al_(7)Cu_(2)Fe phases are squeezed and broken,and the Al_(2)O_(3p) become uniform distribution.The microhardness of as-extruded 2 wt%Al_(2)O_(3p)/7075 composites reaches HV 170.34,increased by 41.5%than as-cast composites.The wear rate of as-extruded 2 wt%Al_(2)O_(3p)/7075 composites is further lower than that of as-cast composites under the same condition.SEM-EDS analyses reveal that the reinforced wear resistance of composites can put down to the protective effect of the Al_(2)O_(3p) reinforced transition layer.After hot extrusion,the transition layer becomes stable,which determines the reinforced wear resistance of the as-extruded composites.展开更多
BNp/Al2O3-SiO2 system ceramic matrix composites with different volume fractions （10%-60%） of hexagonal BN particulates （BNp） were prepared by hot-press sintering technique. Phase components, microstructure, mechan...BNp/Al2O3-SiO2 system ceramic matrix composites with different volume fractions （10%-60%） of hexagonal BN particulates （BNp） were prepared by hot-press sintering technique. Phase components, microstructure, mechanical properties and plasma erosion resistance were also investigated. With the increase of h-BNp content, relative density and Vickers＇ hardness of the composite ceramics decrease, while the flexural strength, elastic modulus and fracture toughness increase and then decrease. The plasma erosion resistance linearly deteriorated with the increase of BNp content which is mainly determined by the density, crystal structure and atomic number of the elements.展开更多
Nanometer 3Y TZP/20%Al 2O 3 (mass fraction) composite powders prepared by the chemical coprecipitation method were pressureless sintered at 1550 ℃ for 2 h. Effects of calcining temperatures at 800 ℃, 1 000 ℃, and 1...Nanometer 3Y TZP/20%Al 2O 3 (mass fraction) composite powders prepared by the chemical coprecipitation method were pressureless sintered at 1550 ℃ for 2 h. Effects of calcining temperatures at 800 ℃, 1 000 ℃, and 1 200 ℃ on phase structure, relative density, and Vicker′s hardness of the sintered bodies were studied. The results show that 1 000 ℃ was the optimal calcining temperature,and the powder calcined was composed of tetragonal zirconia with the Scherrer crystalline size of 6.3 nm. The relative density was up to 98.5% under pressureless sintering, and the sintered body was t ZrO 2(without m ZrO 2)+α Al 2O 3 with the average size of 0.4 μm.展开更多
以纳米ZrO 、微米Al O 为原料,采用无压烧结方式制备了ZTA 复相陶瓷。结果表明:nano-ZrO 的 2 2 3 2加入有利于制备细晶ZTA 复相陶瓷。此外,nano-ZrO 的加入对 Al O 陶瓷的显微结构也产生影响,ZrO ...以纳米ZrO 、微米Al O 为原料,采用无压烧结方式制备了ZTA 复相陶瓷。结果表明:nano-ZrO 的 2 2 3 2加入有利于制备细晶ZTA 复相陶瓷。此外,nano-ZrO 的加入对 Al O 陶瓷的显微结构也产生影响,ZrO 颗粒以 2 2 3 2“晶内型”和晶界型两种形式存在。合理的配方组成及制备工艺有利于 Z r O 以四方亚稳相存在。Z r O 含量为 2 23 0 w t % 时,其四方相含量可达 6 9 %,有利于应力诱导相变增韧,该 Z T A 复相陶瓷的抗弯强度、断裂韧性分别达到 604MPa、6.87MPa·m1/2。展开更多
文摘MoS2/γ－Al2O3 ceramic composite membrane is successfully synthesized by the sol-gel method based on the inorganic salt route. The aluminum hydrate sol derived from the inorganic salt Al(NO3)3, whose transparence and viscosity are 97% and 1.2 × 10-3 Pa. s, respectively, can be formed through adjusting the ratio of the peptizing agent H+ to Al3+ to 0.3. The aluminum hydrate gel at 110℃ is amorphous in structure and is heat-treated in air at 800℃ to form γ－Al2O3. The precursor derived from the mixture solution of ammonium molybdate, thioacetamide and a reducing agent, can be transformed into crystal MoS2 under reducing condition at 800℃. MoS2/γ－Al2O3 composite membrane is an organic whole and bps no gradation from MoS2 layer to γ－Al2O3 Iayer. The separation factor a H2/H2S through the MoS2/γ－Al2O3 composite membrane increase with rising temperature and a H2/H2S at 600℃ is 4.45 higher than the theoretical separation factor produced by the ideal Knudsen diffusion.
基金Project(51965040)supported by the National Natural Science Foundation of ChinaProject(20181BAB206026)supported by the National Science Foundation of Jiangxi Province,China。
文摘The effects of hot extrusion and addition of Al_(2)O_(3p) on both microstructure and tribological behavior of 7075 composites were investigated via optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectrometry(EDS),and transmission electron microscopy(TEM).The experimental consequences reveal that the optimal addition of Al_(2)O_(3p) was 2 wt%.After hot extrusion,the Mg(Zn,Cu,Al)2 phases partially dissolve into the matrix and generate many uniformly distributed aging precipitation particles,the Al_(7)Cu_(2)Fe phases are squeezed and broken,and the Al_(2)O_(3p) become uniform distribution.The microhardness of as-extruded 2 wt%Al_(2)O_(3p)/7075 composites reaches HV 170.34,increased by 41.5%than as-cast composites.The wear rate of as-extruded 2 wt%Al_(2)O_(3p)/7075 composites is further lower than that of as-cast composites under the same condition.SEM-EDS analyses reveal that the reinforced wear resistance of composites can put down to the protective effect of the Al_(2)O_(3p) reinforced transition layer.After hot extrusion,the transition layer becomes stable,which determines the reinforced wear resistance of the as-extruded composites.
基金Project(HIT.NSRIF.2010112)supported by the Fundamental Research Fund for the Central Universities,ChinaProjects(50902030,51021002)supported by the National Natural Science Foundation of China
文摘BNp/Al2O3-SiO2 system ceramic matrix composites with different volume fractions （10%-60%） of hexagonal BN particulates （BNp） were prepared by hot-press sintering technique. Phase components, microstructure, mechanical properties and plasma erosion resistance were also investigated. With the increase of h-BNp content, relative density and Vickers＇ hardness of the composite ceramics decrease, while the flexural strength, elastic modulus and fracture toughness increase and then decrease. The plasma erosion resistance linearly deteriorated with the increase of BNp content which is mainly determined by the density, crystal structure and atomic number of the elements.
文摘Nanometer 3Y TZP/20%Al 2O 3 (mass fraction) composite powders prepared by the chemical coprecipitation method were pressureless sintered at 1550 ℃ for 2 h. Effects of calcining temperatures at 800 ℃, 1 000 ℃, and 1 200 ℃ on phase structure, relative density, and Vicker′s hardness of the sintered bodies were studied. The results show that 1 000 ℃ was the optimal calcining temperature,and the powder calcined was composed of tetragonal zirconia with the Scherrer crystalline size of 6.3 nm. The relative density was up to 98.5% under pressureless sintering, and the sintered body was t ZrO 2(without m ZrO 2)+α Al 2O 3 with the average size of 0.4 μm.
文摘以纳米ZrO 、微米Al O 为原料,采用无压烧结方式制备了ZTA 复相陶瓷。结果表明:nano-ZrO 的 2 2 3 2加入有利于制备细晶ZTA 复相陶瓷。此外,nano-ZrO 的加入对 Al O 陶瓷的显微结构也产生影响,ZrO 颗粒以 2 2 3 2“晶内型”和晶界型两种形式存在。合理的配方组成及制备工艺有利于 Z r O 以四方亚稳相存在。Z r O 含量为 2 23 0 w t % 时,其四方相含量可达 6 9 %,有利于应力诱导相变增韧,该 Z T A 复相陶瓷的抗弯强度、断裂韧性分别达到 604MPa、6.87MPa·m1/2。
