炭酸性コンドライト金属中のシリコン:高温コンデンサスの残骸
まとめ
マーチソン隕石の大きな金属粒にはシリコンが含まれています. これは,特定の圧力と温度で,再均衡することなく,太陽雲のガスから凝縮された合金を示唆しています.
科学分野:
- 宇宙化学 (コスモケミストリー)
- 惑星科学は惑星科学である.
- 材料科学 材料科学とは
背景:
- マーチソン隕石のような炭酸性コンドライトは,太陽系の原始的な材料です.
- 隕石内の金属粒は,太陽系の初期状態についての洞察を提供します.
- これらの粒子の組成を理解することは,星雲のプロセスを再構築するのに役立ちます.
研究 の 目的:
- マーチソン隕石からの例外的に大きな金属粒の組成を分析するために.
- このような金属合金が初期の太陽星雲で形成される可能性のある条件を調査する.
- 金属の粒形成における均衡の役割を決定する.
主な方法:
- 電子マイクロプローブ分析 (EMPA) を使用して,金属粒子の元素組成を決定しました.
- 合金凝縮をモデル化するために熱力学的計算を行いました.
- この研究では,太陽星雲に関連する様々な圧力と温度を考慮した.
主要な成果:
- 分析された金属粒には0.24モルパーセントのシリコンが含まれていた.
- 熱力学モデルによると,このシリコン含有量は,太陽雲のガスからの凝縮と一致している.
- 形成圧力は10^-5から10^-3の大気圏の範囲で計算された.
- この結果は,1200ケルビン以下で周囲のガスとの凝縮後の均衡の欠如を暗示しています.
結論:
- 金属の粒子の中のシリコンの存在は,特定の条件下での nebular 凝縮の自然な結果です.
- この発見は,初期の太陽系における合金形成のモデルを裏付けている.
- この研究は,プライマリネブラの組成物の保存における非均衡プロセスの重要性を強調している.
関連する概念動画
Types of Semiconductors
Intrinsic semiconductors are highly pure materials with no impurities. At absolute zero, these semiconductors behave as perfect insulators because all the valence electrons are bound, and the conduction band is empty, disallowing electrical conduction. The Fermi level is a concept used to describe the probability of occupancy of energy levels by electrons at thermal equilibrium. In intrinsic semiconductors, the Fermi level is positioned at the midpoint of the energy gap at absolute zero. When...
Metal-Semiconductor Junctions
The contact of metal and semiconductor can lead to the formation of a junction with either Schottky or Ohmic behavior.
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The semiconductor's...
Schottky Barriers
Schottky barriers arise when a metal with a work function (Φm) contacts a semiconductor with a different work function (Φs). Initially, electrons transfer until the Fermi levels of the metal and semiconductor align at equilibrium. For instance, if Φm > Φs, the semiconductor Fermi level is higher than the metal's before contact. The semiconductor's...
Network Covalent Solids
Network covalent solids contain a three-dimensional network of covalently bonded atoms as found in the crystal structures of nonmetals like diamond, graphite, silicon, and some covalent compounds, such as silicon dioxide (sand) and silicon carbide (carborundum, the abrasive on sandpaper). Many minerals have networks of covalent bonds.
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
To break or to melt a covalent network solid, covalent bonds must be broken. Because covalent bonds are relatively strong, covalent network solids are typically...
Silica Gel Column Chromatography: Overview
Silica gel column chromatography is a technique for separating compounds using a column packed with silica gel as the stationary phase. This method relies on differences in the polarity of compounds. Based on their polarities, compounds move between the stationary phase (silica gel) and the mobile phase (the solvent), forming discrete bands in the column.
Polar components tend to bind strongly to the silica gel, causing them to move slowly through the column. In contrast, nonpolar compounds...
Polar components tend to bind strongly to the silica gel, causing them to move slowly through the column. In contrast, nonpolar compounds...
Properties of Organometallic Compounds
Organometallic compounds are compounds that contain a carbon–metal bond. Carbon belongs to an organyl group like alkyl, aryl, allyl, or benzyl groups. The metal can be from Group I or Group II of the periodic table, a transition metal, or a semimetal.
Metallic Solids
Metallic solids such as crystals of copper, aluminum, and iron are formed by metal atoms. The structure of metallic crystals is often described as a uniform distribution of atomic nuclei within a “sea” of delocalized electrons. The atoms within such a metallic solid are held together by a unique force known as metallic bonding that gives rise to many useful and varied bulk properties.
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...
All metallic solids exhibit high thermal and electrical conductivity, metallic luster, and malleability. Many...


