Crystal vs Grain
Crystal and grain contain similar components and also perform almost the same functions that make it hard to differentiate between them. Most of the metallurgists refer crystals as grains.
What is grain? Grain can be termed as the smaller variation of a crystal. Crystals are generally formed by solidification of liquid metal from atoms. Each of the grains represents a crystal.
What is a crystal? Crystals can be called as large grains. Crystals have a unique arrangement of the molecules or atoms and a lattice showing symmetry and long-range order.
The symmetry and structure of a crystal helps in determining the physical properties of a substance like its electronic band structure, cleavage and optical transparency. When talking of grains, the size helps in determining certain physical properties like the tensile strength and ductility. The characteristics of substances also depend on the grain property. For example a fine grained substance will be tough and hard whereas a course grained have better electrical leading.
The symmetry in crystals is because of the internal arrangement of atoms. Most of the crystals are composed of three-dimensional arrays of atoms. But the size of grain is different. For example, the size of the grain of solidifying metals depends on the heat transfer and the rate of cooling among other factors.
When the crystal size is determined using X ray diffraction patterns, the grain size is determined by other techniques such as transmission electron microscopy.
Crystal is a word that has been derived from Greek Krustallos, which means “rock-crystal. The word Grain has been derived from old Fr. grein and from Latin granum, which means seed. First this word was used fo seeds and corn and later it was used for other substances.
Summary
1. Grain can be termed as the smaller variation of a crystal.
2. Crystals can be called as large grains. Crystals have a unique arrangement of the molecules or atoms and a lattice showing symmetry and long-range order.
3. Each of the grains represents a crystal.
4. The symmetry and structure of a crystal helps in determining the physical properties of a substance like its electronic band structure, cleavage and optical transparency. When talking of grains, the size helps in determining certain physical properties like the tensile strength and ductility.
5. When the crystal size is determined using X ray diffraction patterns, the grain size is determined by other techniques such as transmission electron microscopy.