Nanoceramics: Synthesis, Characterizations and Applications
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that are used to study nanoceramics are: (i) thermogravimetric analysis (TGA)—
measures weight loss of the material during heating, (ii) differential thermal analysis—measures relative change in the material’s temperature during heating, (iii)
differential scanning calorimetry—measures the amount of heat required to raise
the temperature of the material with respect to temperature, (iv) Brunauer-EmmettTeller method—measures the specific surface area of the material, etc. New techniques are being developed which require less sample quantity which will extend the
applications of thermal analysis in the characterization of nanoceramics.
3.5 Scanning Electron Microscopy (SEM)
Scanning Electron Microscopy is used to study the surface features of the nanomaterials and nanostructured materials by focusing a narrow and high-intensity electron
beam in the range of 5–100 keV over it [58]. The electron beam-sample interaction gives rise to a variety of signals including secondary electrons, backscattered
electrons (BSE), photons, visible light etc. By collecting these signals with suitable detectors, high resolution and high-magnification images of the sample surface
can be obtained. Secondary electrons give information about the morphology and
the topography of the sample surface [59]. Backscattered electrons reveal information about the composition of multiphase samples whereas diffracted backscattered
electrons can give information about the crystallographic orientation in the sample.
SEM is a non-destructive analysis method requiring less or no sample preparation.
Nonconductive samples can be studied by coating them with a thin layer of electrically conductive material such as carbon, gold, etc. in order to avoid or minimize
negative charge accumulation from the incident electron beam [58].
3.6 Transmission Electron Microscopy (TEM)
Transmission Electron Microscopy is a powerful tool used for studying nanoscale
materials. A high energy beam of electrons is focused on a very thin specimen of
thickness less than 200 nm [19]. The electron penetrates the sample and the subsequent electron—atom interaction results in either deflected or undeflected electrons
carrying information about the crystal structure, composition, and defects such as
dislocations and grain boundaries. A high magnification from 50–10
6 can be obtained
by this method revealing finest details of the material even as small as individual
atoms. High resolution—Transmission Electron Microscopy (HRTEM) has a resolution of approximately 0.08 nm. The diffraction pattern of a small selected area
of the sample can be recorded with Selected area electron diffraction (SAED) from
which information about the structure and orientation of the material can be obtained
[60].
141
that are used to study nanoceramics are: (i) thermogravimetric analysis (TGA)—
measures weight loss of the material during heating, (ii) differential thermal analysis—measures relative change in the material’s temperature during heating, (iii)
differential scanning calorimetry—measures the amount of heat required to raise
the temperature of the material with respect to temperature, (iv) Brunauer-EmmettTeller method—measures the specific surface area of the material, etc. New techniques are being developed which require less sample quantity which will extend the
applications of thermal analysis in the characterization of nanoceramics.
3.5 Scanning Electron Microscopy (SEM)
Scanning Electron Microscopy is used to study the surface features of the nanomaterials and nanostructured materials by focusing a narrow and high-intensity electron
beam in the range of 5–100 keV over it [58]. The electron beam-sample interaction gives rise to a variety of signals including secondary electrons, backscattered
electrons (BSE), photons, visible light etc. By collecting these signals with suitable detectors, high resolution and high-magnification images of the sample surface
can be obtained. Secondary electrons give information about the morphology and
the topography of the sample surface [59]. Backscattered electrons reveal information about the composition of multiphase samples whereas diffracted backscattered
electrons can give information about the crystallographic orientation in the sample.
SEM is a non-destructive analysis method requiring less or no sample preparation.
Nonconductive samples can be studied by coating them with a thin layer of electrically conductive material such as carbon, gold, etc. in order to avoid or minimize
negative charge accumulation from the incident electron beam [58].
3.6 Transmission Electron Microscopy (TEM)
Transmission Electron Microscopy is a powerful tool used for studying nanoscale
materials. A high energy beam of electrons is focused on a very thin specimen of
thickness less than 200 nm [19]. The electron penetrates the sample and the subsequent electron—atom interaction results in either deflected or undeflected electrons
carrying information about the crystal structure, composition, and defects such as
dislocations and grain boundaries. A high magnification from 50–10
6 can be obtained
by this method revealing finest details of the material even as small as individual
atoms. High resolution—Transmission Electron Microscopy (HRTEM) has a resolution of approximately 0.08 nm. The diffraction pattern of a small selected area
of the sample can be recorded with Selected area electron diffraction (SAED) from
which information about the structure and orientation of the material can be obtained
[60].