Huaqing XIE
,
Tonggeng XI
,
Qinghong ZHANG
,
Qingren WU
材料科学技术（英）
Nanosized amorphous TiO2 powders with a specific surface area of 501 m2•g-1 were prepared by hydrolysis. After calcined at 400 °C for 2 h, the prepared amorphous TiO2 powders were fully transformed into anatase crystallites with a specific surface area of 141 m2•g-1. Differential scanning calorimetric (DSC) experiments were performed on the samples of nanosized amorphous TiO2 mixed with microsized anatase, nanosized anatase, or nanosized α-Al2O3 respectively. Effects of sample packing, anatase addition, or α-Al2O3 addition on the crystallization behavior of nanosized amorphous TiO2 were analyzed.
关键词:
Crystallization behavior
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Xin TONG
,
Yong CHEN
,
Huiming CHENG
材料科学技术（英）
Carbon nanofiber (CNF)-reinforced polypropylene (CNF/PP) composites with different CNF contents were prepared by melt mixing, and the mechanical properties and crystallization behavior of the CNF/PP composites obtained were investigated. It was found that the tensile modulus of the composites was increased with the addition of CNFs, but their elongation at break and fracture strain energy were decreased, while the tensile strength of the composites was firstly increased and then decreased due to the agglomeration of CNFs at higher loading. Nonisothermal crystallization analysis showed that the CNFs played a role as nucleating agent in PP matrix, which led to increment in the crystallization rate and the degree of crystallinity of PP. Moreover, X-ray diffraction studies showed that the CNFs incorporated in the PP matrix favored the growth of (040)-oriented PP crystals. With the increase in the CNF content, the nucleating and orientation roles of the CNFs were obviously enhanced.
关键词:
Carbon nanofibers
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Hao WANG
,
Xiaoping SONG
,
Xiangdong YAO
,
Haifeng ZHANG
,
Zhuangqi HU
材料科学技术（英）
The crystallization behavior and crystallization kinetics of (Cu60Zr30Ti10)99Sn1 bulk metallic glass was studied by X-ray diffractometry and differential scanning calorimetry. It was found that a two-stage crystallization took place during continuous heating of the bulk metallic glass. Both the glass transition temperature Tg and the crystallization peak temperatures Tp displayed a strong dependence on the heating rate. The activation energy was determined by the Kissinger analysis method. In the first-stage of the crystallization, the transformation of the bulk metallic glass to the phase one occurred with an activation energy of 386 kJ/mol; in the second-stage, the formation of the phase two took place at an activation energy of 381 kJ/mol.
关键词:
Bulk metallic glasses
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