オキシドイットリウムとオキシドアルミニウムの溶融における第1次流体/液体相移行の検出
G N Greaves1, M C Wilding, S Fearn
1Centre for Advanced Functional Materials and Devices, Institute of Mathematics and Physics, Aberystwyth University, Aberystwyth SY23 3BZ, UK. gng@aber.ac.uk
Science (New York, N.Y.)
|October 25, 2008
まとめ
イットリアアルミニウム溶液は,高温で反転可能な第一次元の相変化を示しており,これはナノスケールの液体の分離と原子スケールの構造変化によって証明されています. この現象は,超冷却液体において"ポリアモルフィック・ローター"を生成する.
科学分野:
- マテリアルサイエンス 材料科学
- 物理化学 物理化学
- 凝縮物質物理学 凝縮物質物理学
背景:
- 液体物質の相変遷は,その性質を理解するために極めて重要です.
- 以前の研究では,消火したガラスのイトリアアルミニウム溶液の変異を推論した.
- 接触なしの条件下での高温液体相変異のインシット・スタディは困難です.
研究 の 目的:
- 高い温度でイットリアアルミニウム溶液の相変遷を in situ で調査する.
- これらの移行中のナノスケールと原子スケールの変化を特徴付ける.
- 観測された移行に関連した熱力学的性質を定量化するために.
主な方法:
- 小角X線散射 (SAXS) と広角X線散射 (WAXS) を組み合わせたX線散射.
- 高温で無接触でサンプルを処理するためにエアロダイナミック・レビテーションを活用した.
- 立体構造の進化と浮遊溶融の動的行動が観察されました.
主要な成果:
- 高温でのイットリアアルミニウム溶融における第1次相変異を特定した.
- SAXSは,逆行可能な最大値によって示された,ナノスケールの液体不混合を明らかにしました.
- WAXSは,多面体パッケージの急激なシフトを示し,原子規模の構造変化を示した.
- 観察されたaはaである.
- ポリアモルフロータのロータは,
- 繰り返される移行によって引き起こされる現象である.
結論:
- イトリアアルミニウム溶液における高温移行は,ナノスケールの液体分離と原子スケールの構造的再編成の両方を含む.
- 観察されたポリアモルフなローターは,モラー体積とエントロピーの可逆的な変化の推定を可能にします.
- この研究は,極限条件下での酸化物溶解の複雑な行動に関する新しい洞察を提供します.
関連する概念動画
01:24Solid–Solid Solutions
The temperature-composition phase diagram of two solids, A and B, which are immiscible in the solid phase but form miscible liquids, shows that when the temperature is low, these two exist as separate, pure solids (A and B). As the temperature increases, they transition into a single-phase liquid solution where A and B coexist. Moving from point a1 to a2 in the phase diagram, the composition changes such that solid B begins to separate from the solution, enriching the remaining liquid with A.
01:28Phase Diagrams of Ternary Systems
Consider a ternary system, which is composed of three components: water (W), ethanoic acid (E), and trichloromethane (T). Here, Ethanoic acid (E) is fully miscible with both water (W) and trichloromethane (T), meaning it can mix entirely with either of them. However, water and trichloromethane have partial miscibility, meaning they can only mix to a certain extent, beyond which two separate phases will form.The phase diagram of a ternary system is represented as an equilateral triangle, where...
02:39Phase Transitions: Vaporization and Condensation
The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize (convert into vapor). The process is called vaporization—a surface phenomenon. Vaporization occurs when the thermal motion of the molecules overcome the intermolecular forces, and the molecules (at the surface) escape into the gaseous state. When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules...
02:39Phase Transitions: Melting and Freezing
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
02:33Phase Transitions: Sublimation and Deposition
Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and standard pressure, a piece of dry ice (solid CO2) sublimes, appearing to gradually disappear without ever forming any liquid. Snow and ice sublimate at temperatures below the melting point of water, a slow process that may be accelerated by winds and the reduced atmospheric pressures at high altitudes. When solid iodine is warmed, the solid sublimes...
01:27Two Components: Liquid–Liquid Systems
A pressure-composition phase diagram explicitly describes the behavior of an ideal solution of two volatile liquids under varying pressures and compositions. A pressure-composition diagram has two main curves. The bubble point curve represents the plot of pressure versus liquid mole fraction. It indicates the pressure at which the first bubble of vapor forms from the liquid phase as the system pressure decreases.The dew point curve is the pressure versus vapor mole fraction. It indicates the...