The mechanical characters of CdZnTe crystal were investigated by nanoscratch tests, and the effects of mechanical anisotropy on the material removal rate and surface quality were studied by polishing tests. There is a...The mechanical characters of CdZnTe crystal were investigated by nanoscratch tests, and the effects of mechanical anisotropy on the material removal rate and surface quality were studied by polishing tests. There is a peak of frictional coefficient at the early stage of scratch, and increasing the vertical force will result in the increase of peak value correspondingly. The fluctuation phenomenon of frictional coefficient is generated at high vertical force. The lateral forces show the apparent twofold and threefold symmetries on （110） and （111） planes, respectively. To obtain high surface quality, low polishing pressure and hard direction （〈 T10 〉 directions on （110） plane and 〈 112 〉 directions on （111） plane） should be selected, and to achieve high material removal rate, high polishing pressure and soft direction （〈001〉 directions on （110） plane and 〈 121 〉 directions on （111） plane） should be selected.展开更多
The tribological properties and scratch resistance of MoS_(2)bilayer deposited on SiO_(2)/Si substrates prepared via chemical vapor deposition are investigated.Friction force microscopy(FFM)is employed to investigate ...The tribological properties and scratch resistance of MoS_(2)bilayer deposited on SiO_(2)/Si substrates prepared via chemical vapor deposition are investigated.Friction force microscopy(FFM)is employed to investigate the friction and wear properties of the MoS_(2)bilayer at the nanoscale by applying a normal load ranging from 200 to 1,000 nN.Scratch resistance is measured using the scratch mode in FFM based on a linearly increasing load from 100 to 1,000 nN.Kelvin probe force microscopy(KPFM)is performed to locally measure the surface potential in the tested surface to qualitatively measure the wear/removal of Mos,layers and identify critical loads associated with the individual failures of the top and bottom layers.The analysis of the contact potential difference values as well as that of KPFM,friction,and height images show that the wear/removal of the top and bottom layers in the MoS_(2)bilayer system occurred consecutively.The FFM and KPFM results show that the top MoS_(2)layer begins to degrade at the end of the low friction stage,followed by the bottom layer,thereby resulting in a transitional friction stage owing to the direct contact between the diamond tip and SiO_(2)substrate.In the stable third stage,the transfer of lubricious MoS_(2)debris to the tip apex results in contact between the MoS_(2)-transferred tip and SiO_(2).Nanoscratch test results show two ranges of critical loads,which correspond to the sequential removal of the top and bottom layers.展开更多
基金supported by the Key Project of the National Natural Science Foundation of China (No. 50535020)the Fund of the State Key Laboratory of Solidification Processing in Northwestern Polytechnical University (No. SKLSP200902)
文摘The mechanical characters of CdZnTe crystal were investigated by nanoscratch tests, and the effects of mechanical anisotropy on the material removal rate and surface quality were studied by polishing tests. There is a peak of frictional coefficient at the early stage of scratch, and increasing the vertical force will result in the increase of peak value correspondingly. The fluctuation phenomenon of frictional coefficient is generated at high vertical force. The lateral forces show the apparent twofold and threefold symmetries on （110） and （111） planes, respectively. To obtain high surface quality, low polishing pressure and hard direction （〈 T10 〉 directions on （110） plane and 〈 112 〉 directions on （111） plane） should be selected, and to achieve high material removal rate, high polishing pressure and soft direction （〈001〉 directions on （110） plane and 〈 121 〉 directions on （111） plane） should be selected.
基金This study was supported by the Research Program funded by the SeoulTech(Seoul National University of Science and Technology,Republic of Korea).
文摘The tribological properties and scratch resistance of MoS_(2)bilayer deposited on SiO_(2)/Si substrates prepared via chemical vapor deposition are investigated.Friction force microscopy(FFM)is employed to investigate the friction and wear properties of the MoS_(2)bilayer at the nanoscale by applying a normal load ranging from 200 to 1,000 nN.Scratch resistance is measured using the scratch mode in FFM based on a linearly increasing load from 100 to 1,000 nN.Kelvin probe force microscopy(KPFM)is performed to locally measure the surface potential in the tested surface to qualitatively measure the wear/removal of Mos,layers and identify critical loads associated with the individual failures of the top and bottom layers.The analysis of the contact potential difference values as well as that of KPFM,friction,and height images show that the wear/removal of the top and bottom layers in the MoS_(2)bilayer system occurred consecutively.The FFM and KPFM results show that the top MoS_(2)layer begins to degrade at the end of the low friction stage,followed by the bottom layer,thereby resulting in a transitional friction stage owing to the direct contact between the diamond tip and SiO_(2)substrate.In the stable third stage,the transfer of lubricious MoS_(2)debris to the tip apex results in contact between the MoS_(2)-transferred tip and SiO_(2).Nanoscratch test results show two ranges of critical loads,which correspond to the sequential removal of the top and bottom layers.
