You have a single crystal of 100% pure gold. Identify which of the following defects you would expect to be present at room temperature.
Free surface
Grain boundaries
Vacancies
Inclusions
Substitutional impurity atoms
Interstitial impurity atoms
Vacancies,
Grain boundaries,
Substitutional impurity atoms
Wrong answer is that up here.
Free Surface
Vacancies
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Free Surface
Vacancies
To identify the defects that would be present in a single crystal of 100% pure gold at room temperature, we need some background understanding.
1. Free Surface: A free surface is the boundary between a solid and its surrounding environment. Since we have a single crystal, there are no free surfaces inside the crystal. However, the external surface of the crystal would be a free surface.
2. Grain Boundaries: Grain boundaries are interfaces between individual grains (smaller crystalline regions) of a polycrystalline material. In the case of a single crystal, there are no grain boundaries since there is only one continuous grain.
3. Vacancies: Vacancies are atomic sites within a crystal lattice that are unoccupied by an atom. In any crystal, including single crystals, some vacancies are present due to thermal vibrations. Therefore, vacancies would be expected to be present at room temperature in the single crystal of gold.
4. Inclusions: Inclusions refer to foreign particles or materials present within a host material. Since we have a single crystal of pure gold, there should be no inclusions unless there was accidental contamination during the crystal growth process.
5. Substitutional Impurity Atoms: Substitutional impurity atoms occur when foreign atoms replace some of the host atoms within the crystal lattice. In the case of 100% pure gold, there should be no substitutional impurity atoms.
6. Interstitial Impurity Atoms: Interstitial impurity atoms occur when foreign atoms occupy interstitial sites (spaces between regular lattice positions) within the crystal lattice. Since we have a single crystal of pure gold, there should be no interstitial impurity atoms.
In conclusion, in a single crystal of 100% pure gold at room temperature, we would expect to find vacancies but not grain boundaries, inclusion, substitutional impurity atoms, or interstitial impurity atoms.