概括
研究人员使用脉冲激光切除和原子源合成了新的碳- (C-N) 薄膜. 由此产生的材料显示出超硬应用的潜力,这是由于其独特的β-C(3) N(4) 结构.
科学领域:
- 材料科学 材料科学 材料科学
- 固态化学 固态化学
- 薄膜沉积的情况
背景情况:
- 碳 (C-N) 材料对先进的应用有兴趣.
- 理论预测表明β-C(3) N(4) 可能是一种超硬材料.
- 这种材料的实验合成仍然是一个挑战.
研究的目的:
- 为了合成新的C-N薄膜材料.
- 描述合成电影的组成,粘合和结构.
- 研究合成材料在超硬应用中的潜力.
主要方法:
- 石墨目标的脉冲激光切除.
- 使用强烈的原子源用于薄膜沉积.
- 拉瑟福回散光谱仪用于元素分析.
- 光电子光谱仪用于化学键分析.
- 电子衍射用于结构的确定.
主要成果:
- 成功制备了C-N薄膜,可调节含量高达40%.
- 拉瑟福反散证实了高的加入.
- 光电子光谱学表明没有极化的共价C-N键.
- 电子衍射确定了晶体结构为β-C(3) N(4).
- 合成的C-N固体表现出热强度和硬度.
结论:
- 该研究通过实验合成了β-C(3) N(4),这是理论上预测的超硬材料.
- 合成方法可以控制含量和薄膜特性.
- 新型C-N材料对未来的研究和工程应用具有前景.
相关概念视频
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...
Covalent Bonds
When two atoms share electrons to complete their valence shells they create a covalent bond. An atom’s electronegativity—the force with which shared electrons are pulled towards an atom—determines how the electrons are shared. Molecules formed with covalent bonds can be either polar or nonpolar. Atoms with similar electronegativities form nonpolar covalent bonds; the electrons are shared equally. Atoms with different electronegativities share electrons unequally, creating polar bonds.A Covalent...
Covalent Bonds
Overview
When two atoms share electrons to complete their valence shells, they create a covalent bond. An atom's electronegativity—the force with which shared electrons are pulled towards an atom—determines how the electrons are shared. Molecules formed with covalent bonds can be either polar or nonpolar. Atoms with similar electronegativities form nonpolar covalent bonds; the electrons are shared equally. Atoms with different electronegativities share electrons unequally, creating polar bonds.
When two atoms share electrons to complete their valence shells, they create a covalent bond. An atom's electronegativity—the force with which shared electrons are pulled towards an atom—determines how the electrons are shared. Molecules formed with covalent bonds can be either polar or nonpolar. Atoms with similar electronegativities form nonpolar covalent bonds; the electrons are shared equally. Atoms with different electronegativities share electrons unequally, creating polar bonds.
Molecular and Ionic Solids
Crystalline solids are divided into four types: molecular, ionic, metallic, and covalent network based on the type of constituent units and their interparticle interactions.
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Solid–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.
The Equilibrium Constant
Consider the oxidation of sulfur dioxide:


