摘要
采用机械高能球磨法制备了纳米氧化镧/蛇纹石复合微粉,通过不同温度下的热处理和借助SEM、XRD和FTIR等对热处理产物表征研究了纳米氧化镧对超细蛇纹石微粉热相变行为的影响。结果表明:纳米氧化镧对蛇纹石微粉的热相变具有显著的催化效应。虽然其未改变蛇纹石微粉脱羟反应的3个特征阶段及主控机制,但能够与[SiO4]四面体形成钙钛矿型过渡产物,促进蛇纹石层间活性氧和自由水的传输,增大其反应速率及程度,降低其结构和热力学稳定性,促进其层间失稳和相变。
Nano-scale lanthanum/serpentine composite powders were prepared by high-energy mechanical ball-milling method. The as- prepared powders were heat treated at different temperatures and the as-treated products were characterized by SEM, XRD and FTIR in order to study the effect of nano-scale lanthanum on the thermal phase transformation behavior of ultrafine serpentine powders. Results show that nano-scale lanthanum can present significant catalytic effects on the thermal phase transformation of serpentine powders. With the addition of lanthanum particles, the three characteristic stages and dominant mechanisms for the dehydration reaction of serpentine powders keep unchanged while the corresponding reaction speed and extent can be significantly improved, the structural and thermodynamic stability is reduced, and the interlayer collapse and phase transformation are enhanced. The main reason for the above results is that the lanthanum combines with [ SiO4 ] tetrahedron to form an apatite-type transitional compound, which can promote the active oxygen atoms and free water conduction between the layers of serpentine.
出处
《材料热处理学报》
EI
CAS
CSCD
北大核心
2013年第12期18-23,共6页
Transactions of Materials and Heat Treatment
基金
国家自然科学基金(51205183)
江苏省自然科学基金(BK2012475)
南京工程学院创新基金(YKJ201204)
关键词
纳米氧化镧
蛇纹石微粉
热相变
nano-scale lanthanum
serpentine powders
thermal phase transformation
