Ⅰ. INTRODUCTION As nanosolid is compacted from ultrafine particles, a large volume fraction of the material is constituted by grain boundaries or interfaces. Because of the small size and boundary effects, the proper...Ⅰ. INTRODUCTION As nanosolid is compacted from ultrafine particles, a large volume fraction of the material is constituted by grain boundaries or interfaces. Because of the small size and boundary effects, the properties of nanosolids are superior to those of the traditional materials with the same compositions. The gas sensing properties of"nano SnO<sub>2</sub> solids are high sensitivity and rapid respgnding speed, which increase with the decrease of crystal grain size.展开更多
Internal friction and modulus measurements of nano ZrO_2 solids for different particle sizes (including original compacted and annealed samples) were systematically carried out from room temperature to -200℃. It was ...Internal friction and modulus measurements of nano ZrO_2 solids for different particle sizes (including original compacted and annealed samples) were systematically carried out from room temperature to -200℃. It was found that the three peaks (P_1, P_2 and P_3 corresponding to ascending measurement, or P_1~', P_2~' and P_3~' corresponding to descending measurement) appeared. By investigating the behavior of internal friction peaks (P_1, P_2, P_3 orP_1~' P_2~', P_3~'), it is indicated that the origin of peak P_3 or P_3~' can be attributed to grain boundary relaxation, that is, it is caused by slip of the grain boundaries in nano ZrO_2 solids. The peak P_2 (or P_2~')and P_1 (or P_1~') may possibly be associated with phase transformation of nano ZrO_2 solids at low temperature range. The energy dispersion decreases and the modulus increases notably with the increase in annealing temperature of the nano samples.展开更多
基金Project supported by the Laboratory of Internal Friction and Defects in Solids, Academia Sinica
文摘Ⅰ. INTRODUCTION As nanosolid is compacted from ultrafine particles, a large volume fraction of the material is constituted by grain boundaries or interfaces. Because of the small size and boundary effects, the properties of nanosolids are superior to those of the traditional materials with the same compositions. The gas sensing properties of"nano SnO<sub>2</sub> solids are high sensitivity and rapid respgnding speed, which increase with the decrease of crystal grain size.
基金Project supported by Laboratory of Internal Friction and Defects in Solids, Academia Sinica
文摘Internal friction and modulus measurements of nano ZrO_2 solids for different particle sizes (including original compacted and annealed samples) were systematically carried out from room temperature to -200℃. It was found that the three peaks (P_1, P_2 and P_3 corresponding to ascending measurement, or P_1~', P_2~' and P_3~' corresponding to descending measurement) appeared. By investigating the behavior of internal friction peaks (P_1, P_2, P_3 orP_1~' P_2~', P_3~'), it is indicated that the origin of peak P_3 or P_3~' can be attributed to grain boundary relaxation, that is, it is caused by slip of the grain boundaries in nano ZrO_2 solids. The peak P_2 (or P_2~')and P_1 (or P_1~') may possibly be associated with phase transformation of nano ZrO_2 solids at low temperature range. The energy dispersion decreases and the modulus increases notably with the increase in annealing temperature of the nano samples.
