The gaseous Pr-penetration is a new method to modify ceramics, which is expected to be a promising method for producing new conductor ceramic materials. The gaseous penetration of Pr into PbTiO_3 ceramics and their im...The gaseous Pr-penetration is a new method to modify ceramics, which is expected to be a promising method for producing new conductor ceramic materials. The gaseous penetration of Pr into PbTiO_3 ceramics and their improved electric properties were reported. Through XRD, EPMA and SEM analysis,it is confirmed that the gaseous penetration makes Pr enter into PbTiO_3 ceramics, and the new compound of Pr_2Ti_2O_7 is formed by the penetration of Pr in the gaseous state. The formed new Pr_2Ti_2O_7-PbTiO_3 ceramic materials have a significant change in electric properties. The room temperature resistivity decreases from 2.0×10^(10) Ω·m to 9.487 Ω·m. The grain resistance and the grain boundary resistance decrease with increase in temperature, and the PTCR effect disappears. The tendency of transition to a conductive body is manifest.展开更多
Traditional metal conductive fillers are expensive and prone to oxidation. Thus, the development of new conductive powders as fillers is urgently needed. A novel gaseous penetration technology was adopted to prepare L...Traditional metal conductive fillers are expensive and prone to oxidation. Thus, the development of new conductive powders as fillers is urgently needed. A novel gaseous penetration technology was adopted to prepare La-doped medical stone powders(La-MSPs), which are inexpensive mesoporous materials, as a new kind of conductive filler material. The prepared La-MSPs attained a resistivity of 450 ?·m and were used as a filler to prepare conductive coatings with epoxy resin as the resin matrix. The influence of the La-MSPs dosage on the resistance and hardness of the coatings was also determined. The resistance and the hardness both decreased with increasing filler dosage. Finally, the optimum recipe of the conductive coatings with the most suitable fillers dosage(55 wt%) was obtained. The hardness and resistance of the coatings with 55 wt% La-MSPs were HV 4 and 5.5 × 10~7 ?, respectively.展开更多
BaTiO3∶Mn0.006Smx(x=0.001, 0.002, 0.003, 0.004, 0.006 respectively) ceramics were prepared by using sol-gel method and their resistivities at different temperatures were measured. The results showed that Mn element m...BaTiO3∶Mn0.006Smx(x=0.001, 0.002, 0.003, 0.004, 0.006 respectively) ceramics were prepared by using sol-gel method and their resistivities at different temperatures were measured. The results showed that Mn element may enhance the PTC characteristics of BaTiO3 ceramics. But the doped Mn element deteriorated the room temperature resistivities of the modified BaTiO3 ceramics which were greater than 105 Ω·m. Then, rare earth element Sm was penetrated into BaTiO3∶Mn0.06Smx ceramics in gaseous state, which largely decreased the room temperature resistivity to 3.20 Ω·m, and appeared as a NTC effect instead of PTC effect. The forming mechanism of NTC effect was explored through analyses of SEM and electric properties of Sm-penetrated BaTiO3∶Mn0.006Smx ceramics.展开更多
The gaseous penetration of La-Ce into PbTiO3 ceramics is reported. The compounds of La2Ti6O15 and CeTi21O38 are formed and the new La2Ti6O15-CeTi21O38-PbTiO3 ceramics are prepared by the penetration of La and Ce in th...The gaseous penetration of La-Ce into PbTiO3 ceramics is reported. The compounds of La2Ti6O15 and CeTi21O38 are formed and the new La2Ti6O15-CeTi21O38-PbTiO3 ceramics are prepared by the penetration of La and Ce in the gaseous state. The new ceramic materials have a significant change in electric properties. The room temperature resistivity decreases from 2.0×1010 to 0.248 Ω. m, and the grain resistance exhibits an obvious PTCR effect with the change of temperature. However, the grain boundary resistance decreases rapidly with increase in temperature. The change rule of the total resistance is similar to that of the grain boundary, and the PTCR effect disappears and the tendency of transition to a conductive body is manifest. The XPS analysis suggests that the particles that are Pb, Ti, La and Ce in La2Ti6O15-CeTi21O38-PbTiO3 ceramics all change their valence and lead to decreasing resistivity, and the bound energy peak values of elements in La2Ti6O15-CeTi21O38-PbTiO3 ceramics are also reported. The La2Ti6O15-CeTi21O38-PbTiO3 ceramics have a better thermal stability in high temperatures through TG-DTA analysis.展开更多
文摘The gaseous Pr-penetration is a new method to modify ceramics, which is expected to be a promising method for producing new conductor ceramic materials. The gaseous penetration of Pr into PbTiO_3 ceramics and their improved electric properties were reported. Through XRD, EPMA and SEM analysis,it is confirmed that the gaseous penetration makes Pr enter into PbTiO_3 ceramics, and the new compound of Pr_2Ti_2O_7 is formed by the penetration of Pr in the gaseous state. The formed new Pr_2Ti_2O_7-PbTiO_3 ceramic materials have a significant change in electric properties. The room temperature resistivity decreases from 2.0×10^(10) Ω·m to 9.487 Ω·m. The grain resistance and the grain boundary resistance decrease with increase in temperature, and the PTCR effect disappears. The tendency of transition to a conductive body is manifest.
基金financially supported by the Projects of Application Technology and Development of Harbin (No. 2016RAXXJ024)
文摘Traditional metal conductive fillers are expensive and prone to oxidation. Thus, the development of new conductive powders as fillers is urgently needed. A novel gaseous penetration technology was adopted to prepare La-doped medical stone powders(La-MSPs), which are inexpensive mesoporous materials, as a new kind of conductive filler material. The prepared La-MSPs attained a resistivity of 450 ?·m and were used as a filler to prepare conductive coatings with epoxy resin as the resin matrix. The influence of the La-MSPs dosage on the resistance and hardness of the coatings was also determined. The resistance and the hardness both decreased with increasing filler dosage. Finally, the optimum recipe of the conductive coatings with the most suitable fillers dosage(55 wt%) was obtained. The hardness and resistance of the coatings with 55 wt% La-MSPs were HV 4 and 5.5 × 10~7 ?, respectively.
文摘BaTiO3∶Mn0.006Smx(x=0.001, 0.002, 0.003, 0.004, 0.006 respectively) ceramics were prepared by using sol-gel method and their resistivities at different temperatures were measured. The results showed that Mn element may enhance the PTC characteristics of BaTiO3 ceramics. But the doped Mn element deteriorated the room temperature resistivities of the modified BaTiO3 ceramics which were greater than 105 Ω·m. Then, rare earth element Sm was penetrated into BaTiO3∶Mn0.06Smx ceramics in gaseous state, which largely decreased the room temperature resistivity to 3.20 Ω·m, and appeared as a NTC effect instead of PTC effect. The forming mechanism of NTC effect was explored through analyses of SEM and electric properties of Sm-penetrated BaTiO3∶Mn0.006Smx ceramics.
文摘The gaseous penetration of La-Ce into PbTiO3 ceramics is reported. The compounds of La2Ti6O15 and CeTi21O38 are formed and the new La2Ti6O15-CeTi21O38-PbTiO3 ceramics are prepared by the penetration of La and Ce in the gaseous state. The new ceramic materials have a significant change in electric properties. The room temperature resistivity decreases from 2.0×1010 to 0.248 Ω. m, and the grain resistance exhibits an obvious PTCR effect with the change of temperature. However, the grain boundary resistance decreases rapidly with increase in temperature. The change rule of the total resistance is similar to that of the grain boundary, and the PTCR effect disappears and the tendency of transition to a conductive body is manifest. The XPS analysis suggests that the particles that are Pb, Ti, La and Ce in La2Ti6O15-CeTi21O38-PbTiO3 ceramics all change their valence and lead to decreasing resistivity, and the bound energy peak values of elements in La2Ti6O15-CeTi21O38-PbTiO3 ceramics are also reported. The La2Ti6O15-CeTi21O38-PbTiO3 ceramics have a better thermal stability in high temperatures through TG-DTA analysis.
