In situ observation of phase transformation in iron carbide nanocrystals.

Title	In situ observation of phase transformation in iron carbide nanocrystals.
Authors	L.Thanh Cuong; N.Duc Dung; T.Quoc Tuan; N.Thi Khoi; P.Thanh Huy; N.Ngoc Ha
Journal	Micron
DOI	10.1016/j.micron.2017.10.009
Abstract	This paper reports on the in situ observation of phase transformation in an iron carbide nanocrystal encapsulated in a graphitic shell by means of high resolution transmission electron microscopy (HR-TEM). A Fe7C3 nanocrystal in orthorhombic (o-Fe7C3) structure with carbon graphitic cover is captured at the initial time of the experiment. Under the projection of a high-energy electron beam (200kV), the graphitic carbon layer evaporates gradually and structural changes in orthorhombic (o-Fe7C3) crystal manifests simultaneously. Specifically, changes in crystal direction happens first and then the crystal structure switching between orthorhombic and hexagonal (h-Fe7C3) follows. Details analysis and conclusive evidences of the phase structure and transformation are presented and discussed. The appearance of o-Fe7C3 structure is captured for about 92min over 100min of observation, indicating the preference of o-Fe7C3 form over h-Fe7C3 form.
Citation	L.Thanh Cuong; N.Duc Dung; T.Quoc Tuan; N.Thi Khoi; P.Thanh Huy; N.Ngoc Ha.In situ observation of phase transformation in iron carbide nanocrystals.. Micron. 2018;104:6165. doi:10.1016/j.micron.2017.10.009

Related Elements

Iron

26 Fe 55.845000000 Iron

See more Iron products. Iron (atomic symbol: Fe, atomic number: 26) is a Block D, Group 8, Period 4 element with an atomic weight of 55.845. The number of electrons in each of Iron's shells is 2, 8, 14, 2 and its electron configuration is [Ar] 3d⁶ 4s². Iron Bohr Model The iron atom has a radius of 126 pm and a Van der Waals radius of 194 pm. Iron was discovered by humans before 5000 BC. In its elemental form, iron has a lustrous grayish metallic appearance. Iron is the fourth most common element in the Earth's crust and the most common element by mass forming the earth as a whole. Iron is rarely found as a free element, since it tends to oxidize easily; it is usually found in minerals such as magnetite, hematite, goethite, limonite, or siderite. Elemental Iron Though pure iron is typically soft, the addition of carbon creates the alloy known as steel, which is significantly stronger.