DSC Investigation of Phase Transitions in System LaH2-LaH3
来源期刊：JOURNAL OF RARE EARTHS2002年第2期
论文作者：王龙妹
Key words：rare earths; lanthanum; LaH2-LaH3; Differential scanning calorimetry; phase diagram;
Abstract: Differential scanning calorimetry (DSC) measurements of 37 polycrystalline LaHx (2.0＜x＜3.0) were performed in this work. Samples were synthesized by a direct reaction of a metal with hydrogen at temperatures higher than 250 ℃ (depending on the final composition). DSC measurements were performed in the temperature range of 110～400 K. For the samples in the range of 2.13＜x＜2.40 single DSC peaks were detected. In the composition range x＞2.45 much more complicated DSC signals (double, triple etc. peaks) were observed which some of them were up to 4 phase transformations. Based on these measurements and carried out on high purity samples and supported by high accuracy hydrogen content determination, a new T-x phase diagram for 110＜T＜400 K and 2＜x＜3(LaHx) was proposed. This new phase diagram shows an up to now unknown complexity phase relationships with the existence of at least 11 of phases at T＜400 K.
王龙妹1
(1.Central Iron & Steel Research Institute, Beijing 100081, China)
Abstract:Differential scanning calorimetry (DSC) measurements of 37 polycrystalline LaHx (2.0＜x＜3.0) were performed in this work. Samples were synthesized by a direct reaction of a metal with hydrogen at temperatures higher than 250 ℃ (depending on the final composition). DSC measurements were performed in the temperature range of 110～400 K. For the samples in the range of 2.13＜x＜2.40 single DSC peaks were detected. In the composition range x＞2.45 much more complicated DSC signals (double, triple etc. peaks) were observed which some of them were up to 4 phase transformations. Based on these measurements and carried out on high purity samples and supported by high accuracy hydrogen content determination, a new T-x phase diagram for 110＜T＜400 K and 2＜x＜3(LaHx) was proposed. This new phase diagram shows an up to now unknown complexity phase relationships with the existence of at least 11 of phases at T＜400 K.
Key words:rare earths; lanthanum; LaH2-LaH3; Differential scanning calorimetry; phase diagram;
【全文内容正在添加中】
