Microscopic Analysis of Ceramic Materials.pptx

This presentation is about the various methods of microscopic analysis of Ceramic materials.

1. Seminar and Technical writing (STW) on MICROSCOPIC ANALYSIS OF CERAMICS Presentation By Purnima Satapathy 120CR0651

2. Table of Contents

3. Introduction Need of Microscopic analysis of ceramics To get detailed understanding of the material's microstructure. To identify the factors such as grain boundaries, defects, and phases. To develop processing methods and compositions to optimize properties like strength, conductivity, and thermal stability. The microscopic analysis techniques can be divided into two broad categories: Light Microscopy (e.g.: Optical Microscope) Electron Microscopy (e.g.: SEM, AFM, TEM, etc.)

4. Light Microscopy Vs Electron Microscopy Parameter Light Microscopy Electron Microscopy Principle of Operation Uses Visible light Uses a beam of accelerated electrons Resolution Low ( ~200 nm) High (~0.1nm) Magnification 2000-2500 times 10000-1000000 times Sample Preparation Simpler Process More extensive process Depth of Field Larger depth of field Narrower Depth of field Applications Widely used for biological studies, medical diagnostics, material sciences, and routine laboratory work Particularly suited for high-resolution imaging of subcellular structures, nanomaterials, surfaces, and interfaces in materials science, nanotechnology, biology, and semiconductor research.

5. Techniques of Microscopic Analysis

6. Details of Microscopic Analysis Techniques:- Optical Microscopy: Working Principle Uses visible light and a system of lenses to generate magnified images of small objects. Sample Preparation Sample preparation process involves the following steps: Cutting of specimen (using low speed diamond saw to cause less damage to the sample) Mounting of specimens (to allow the handling of specimens without damaging them) Grinding (using wet silicon Carbide paper to remove the damaged layer from the specimen surface) Polishing (Using abrasive diamond particles and oily lubricants) Etching (used to reveal the microstructure of the sample through selective chemical attack) Application in Ceramic Industry Used to examine the microstructures of ceramic materials, including grain size, distribution, and orientation in a broad way. Used for measurement of surface roughness, hardness and tribological application. Fig.1: Optical Microscope

7. 2. Scanning Electron Microscopy (SEM): Working Principle: Scanning Electron Microscope (SEM) scans the surfaces using a beam of electrons moving at low energy to focus and scan the specimens. Electrons from the source propels very fast moving down the optic axis. The speed of the electrons are controlled by adjusting the magnetic field (using the condenser lenses) in the optic axis. There is a scanning coil which takes electron beam and scans it on the surface. Electrons get reflected or they have some other interactions with the specimen that generates some sort of detectable signals, which are then picked by the detector and then shown on the screen. Sample Preparation: SEM is mostly used to study the surface morphology; hence bulk specimens are normally used, and the sample preparation is simpler than for transmission electron microscopy. For effective viewing of a sample in the SEM it is usually necessary for the surface of the specimen to be electrically conducting. For non-conducting samples such as ceramics , polymers and biological materials, the samples are usually coated with a thin conducting layer (~10nm) of Gold or Carbon (usually this layering is done by sputtering). Care must be taken with the non-conducting samples so that while coating the sample surface with conducting layer it should not mask the actual surface features.

8. Application in Ceramic Industry: SEM allows for high-resolution imaging of ceramic microstructures, revealing features such as grain size, shape, porosity, particle size and morphology, and distribution of phases (EDS analysis). SEM can be used to examine the surface morphology of ceramic materials, including roughness, texture, and surface coatings. Fig.2: Schematic Diagram of SEM Parts of SEM: Electron Source: This is where electrons are produced under thermal heat at a voltage of 1-40kV. There are three types of electron sources that can be used i.e., Tungsten filament, Lanthanum hexaboride, and Field emission gun (FEG) Lenses : I t has several condenser lenses that focus the beam of electrons from the source through the column forming a narrow beam of electrons that form a spot called a spot size. Scanning Coil : they are used to deflect the beam over the specimen surface. Detector: It’s made up of several detectors that can differentiate the secondary electrons, backscattered electrons, and diffracted backscattered electrons. The functioning of the detectors highly depends on the voltage speed, the density of the specimen. The display device (data output devices) Power supply Vacuum system

9. SEM vs FESEM: Parameters SEM FESEM Electron Source Tungsten Filament Field Emission Gun Resolution 1-10nm Below 1 nm Beam Current Higher Lower Depth of Field Limited Extended Vacuum Requirement High vacuum environment Can work in both high and low vacuum environment Fig.4: Field Emission Scanning Electron Microscope (FESEM) Fig.3: Scanning Electron Microscope (SEM)

10. 3. Transmission Electron Microscope (TEM): Working Principle: The working principle of the Transmission Electron Microscope (TEM) is like the light microscope. T he major difference is that light microscopes use light rays to focus and produce an image while the TEM uses a beam of electrons to focus on the specimen, to produce an image. The condenser lens helps to control the electron speed. The electrons go through the specimen and then these are imaged through eye piece. Electrons have a shorter wavelength than light. The mechanism of a light microscope is that an increase in resolution power decreases the wavelength of the light, but in the TEM, when the electron illuminates the specimen, the resolution power increases increasing the wavelength of the electron transmission. The wavelength of the electrons is about 0.005nm which is 100,000X shorter than that of light, hence TEM has better resolution than that of the light microscope, of about 1000times. In SEM, the beam of electrons is scanning on the surface of specimen and looking for interactions that are generated out of it, but in TEM, electrons go right through the specimen and are looked at on the other side. Sample Preparation: The sample should be flat and thin (few nanometres in thickness) so that the electrons transmit through it. The sample preparation techniques can be divided into two basic approaches. First is removal of unwanted material, either by chemical or by mechanical means. Second is cutting in which the sample is cleaved along crystallographic planes. For electrically conductive materials the process of electropolishing is used to prepare the sample surface. For ceramics and polymers, the samples are prepared using mechanical polishing in which a paper of SiC is used to polish the sample surface.

11. Application in Ceramic Industry: TEM is used for microstructural analysis, phase identification, defect analysis, nanostructure characterization, chemical composition analysis, etc. Fig.5: Schematic Diagram of TEM Parts of TEM: Electron Gun: This is the part of the Transmission Electron Microscope responsible for producing electron beams. Image Producing System: It’s made up of the objective lens, a movable stage or holding the specimen, intermediate and projector lenses. They function by focusing the passing electrons through the specimen forming a highly magnified image. Image Recording System: It’s made up of the fluorescent screen used to view and to focus on the image. They also have a digital camera that permanently records the images captured after viewing.

12. TEM VS STEM: Parameters TEM STEM Operating Principle Transmits a beam of electrons through a thin sample. Scans a focused beam of electrons across the sample. Imaging Method Creates a 2D projection of sample’s Interior by capturing the transmitted electrons that pass through the sample Generates images by scanning a focused electron beam across the sample in a raster pattern. Resolution Offers higher resolution for imaging atomic-scale features in two-dimensional projections. Higher resolution than TEM, especially in imaging three-dimensional structures Sample Thickness Thin samples (less than 200nm thick). Thicker samples can be used. Fig.6: Transmission Electron Microscope Fig.7: Scanning Transmission Electron Microscope

13. 4. Atomic Force Microscope (AFM):- Working Principle: The Atomic Force Microscope works on the principle measuring intermolecular forces and sees atoms by using probed surfaces of the specimen in nanoscale.  Its functioning is enabled by three of its major working principles that include Surface sensing, Detection, and Imaging. Surface Sensing: AFM uses a cantilever with a sharp tip to scan over the sample surface. As the tip approaches the surface, attractive forces between the tip and the sample cause deflection of the cantilever. Detection Mechanism: A laser beam is directed onto the back of the cantilever, and its reflection is detected by a position-sensitive photo-diode (PSPD). The deflection and change in direction of the reflected beam are tracked and recorded by the PSPD. Imaging Process : The AFM scans the cantilever over the sample surface, monitoring the deflection of the beam caused by variations in surface height. This generates an accurate topographical map of the sample surface. Sample Preparation: Sample preparation generally involves selecting a suitable substrate, activating and binding the sample to the substrate, and finally visualizing. 

14. The sample preparation for AFM can be described in following steps:

15. Application in Ceramic Industry: AFM is used for Surface Morphology Characterization, defect analysis, Surface Modification Studies, Nanomechanical Property Measurements like hardness, elastic modulus, and adhesion strength of ceramic materials at the nanoscale, Electrical Characterization, Surface Functionalization and Nanopatterning using techniques like Dip-Pen Nanolithography (DPN) ,etc. Fig.8: Atomic Force Microscope (AFM)

16. 5. X-Ray Diffraction (XRD):- Working Principle: The working principle of XRD method can be described as follows: Fig.9: Working Principle of XRD technique

17. Methods of XRD Technique: Methods Of XRD Wavelength Angle Specimen Laue Method Variable Fixed Single crystal Rotating Crystal Method Fixed Variable (in parts) Single crystal Power Method Fixed Variable Powdered Fig.10: Laue method, Rotating Crystal method, and Powder method of XRD technique

18. Application in Ceramic Industry: It is a nondestructive technique. Used for identify crystalline phases and orientation. Used for measure ment of thickness of thin films and multilayers. Used to determine structural properties and atomic arrangement. Fig.11: XRD Setup

19. Comparison of Different Microscopic Analysis Techniques Parameters Optical Microscope Scanning Electron Microscope Transmission Electron Microscope Atomic Force Microscope X-Ray Diffraction Resolution 1 μ m-1mm 1 0nm-100mm 0.1nm-10mm 0.1 nm-10nm (0.001nm in advanced conditions) 0.1nm-10mm Depth of Field Limited Nanometer scale resolution Sub nanometer scale Atomic Scale Crystalline structure Sample preparation Minimal Extensive Extremely thin samples Minimal Crystal form or powdered form Applications Grain characteristics like pores Grains and grain Boundary Characteristics Grains and grain Boundary Characteristics Topography imaging, nanoscale mechanical property mapping Phase identification, crystal structure determination, texture analysis

20. CONCLUSIONS:

21. THANK YOU