Materials Characterization

Yang Leng is Professor, specialized in materials science and engineering, at The Hong Kong University of Science and Technology (HKUST). His research focuses on mechanical behavior of engineering materials, biomedical materials, and novel materials processing. Professor Leng has extensively published in international journals. In addition, he has actively engaged in industrial consultancy. His contribution to teaching materials science and engineering is exemplified by the Teaching Excellence Appreciation award from the HKUST.

• 1 Light Microscopy 11.1 Optical Principles 11.1.1 Image Formation 11.1.2 Resolution 31.1.2.1 Effective Magnification 51.1.2.2 Brightness and Contrast 51.1.3 Depth of Field 61.1.4 Aberrations 71.2 Instrumentation 91.2.1 Illumination System 91.2.2 Objective Lens and Eyepiece 131.2.2.1 Steps for Optimum Resolution 151.2.2.2 Steps to Improve Depth of Field 151.3 Specimen Preparation 151.3.1 Sectioning 161.3.1.1 Cutting 161.3.1.2 Microtomy 171.3.2 Mounting 171.3.3 Grinding and Polishing 191.3.3.1 Grinding 191.3.3.2 Polishing 211.3.4 Etching 231.4 Imaging Modes 261.4.1 Bright-Field and Dark-Field Imaging 261.4.2 Phase-Contrast Microscopy 271.4.3 Polarized-Light Microscopy 301.4.4 Nomarski Microscopy 351.4.5 Fluorescence Microscopy 371.5 Confocal Microscopy 391.5.1 Working Principles 391.5.2 Three-Dimensional Images 41References 45Further Reading 452 X-Ray Diffraction Methods 472.1 X-Ray Radiation 472.1.1 Generation of X-Rays 472.1.2 X-Ray Absorption 502.2 Theoretical Background of Diffraction 522.2.1 Diffraction Geometry 522.2.1.1 Bragg’s Law 522.2.1.2 Reciprocal Lattice 532.2.1.3 Ewald Sphere 552.2.2 Diffraction Intensity 582.2.2.1 Structure Extinction 602.3 X-Ray Diffractometry 622.3.1 Instrumentation 622.3.1.1 System Aberrations 642.3.2 Samples and Data Acquisition 652.3.2.1 Sample Preparation 652.3.2.2 Acquisition and Treatment of Diffraction Data 652.3.3 Distortions of Diffraction Spectra 672.3.3.1 Preferential Orientation 672.3.3.2 Crystallite Size 682.3.3.3 Residual Stress 692.3.4 Applications 702.3.4.1 Crystal-Phase Identification 702.3.4.2 Quantitative Measurement 722.4 Wide-Angle X-Ray Diffraction and Scattering 752.4.1 Wide-Angle Diffraction 762.4.2 Wide-Angle Scattering 79References 82Further Reading 823 Transmission Electron Microscopy 833.1 Instrumentation 833.1.1 Electron Sources 843.1.1.1 Thermionic Emission Gun 853.1.1.2 Field Emission Gun 863.1.2 Electromagnetic Lenses 873.1.3 Specimen Stage 893.2 Specimen Preparation 903.2.1 Prethinning 913.2.2 Final Thinning 913.2.2.1 Electrolytic Thinning 913.2.2.2 Ion Milling 923.2.2.3 Ultramicrotomy 933.3 Image Modes 943.3.1 Mass–Density Contrast 953.3.2 Diffraction Contrast 963.3.3 Phase Contrast 1013.3.3.1 Theoretical Aspects 1023.3.3.2 Two-Beam and Multiple-Beam Imaging 1053.4 Selected-Area Diffraction (SAD) 1073.4.1 Selected-Area Diffraction Characteristics 1073.4.2 Single-Crystal Diffraction 1093.4.2.1 Indexing a Cubic Crystal Pattern 1093.4.2.2 Identification of Crystal Phases 1123.4.3 Multicrystal Diffraction 1143.4.4 Kikuchi Lines 1143.5 Images of Crystal Defects 1173.5.1 Wedge Fringe 1173.5.2 Bending Contours 1203.5.3 Dislocations 122References 126Further Reading 1264 Scanning Electron Microscopy 1274.1 Instrumentation 1274.1.1 Optical Arrangement 1274.1.2 Signal Detection 1294.1.2.1 Detector 1304.1.3 Probe Size and Current 1314.2 Contrast Formation 1354.2.1 Electron–Specimen Interactions 1354.2.2 Topographic Contrast 1374.2.3 Compositional Contrast 1394.3 Operational Variables 1414.3.1 Working Distance and Aperture Size 1414.3.2 Acceleration Voltage and Probe Current 1444.3.3 Astigmatism 1454.4 Specimen Preparation 1454.4.1 Preparation for Topographic Examination 1464.4.1.1 Charging and Its Prevention 1474.4.2 Preparation for Microcomposition Examination 1494.4.3 Dehydration 1494.5 Electron Backscatter Diffraction 1514.5.1 EBSD Pattern Formation 1514.5.2 EBSD Indexing and Its Automation 1534.5.3 Applications of EBSD 1554.6 Environmental SEM 1564.6.1 ESEM Working Principle 1564.6.2 Applications 158References 160Further Reading 1605 Scanning Probe Microscopy 1635.1 Instrumentation 1635.1.1 Probe and Scanner 1655.1.2 Control and Vibration Isolation 1655.2 Scanning Tunneling Microscopy 1665.2.1 Tunneling Current 1665.2.2 Probe Tips and Working Environments 1675.2.3 Operational Modes 1685.2.4 Typical Applications 1695.3 Atomic Force Microscopy 1705.3.1 Near-Field Forces 1705.3.1.1 Short-Range Forces 1715.3.1.2 van der Waals Forces 1715.3.1.3 Electrostatic Forces 1715.3.1.4 Capillary Forces 1725.3.2 Force Sensors 1725.3.3 Operational Modes 1745.3.3.1 Static Contact Modes 1765.3.3.2 Lateral Force Microscopy 1775.3.3.3 Dynamic Operational Modes 1775.3.4 Typical Applications 1805.3.4.1 Static Mode 1805.3.4.2 Dynamic Noncontact Mode 1815.3.4.3 Tapping Mode 1825.3.4.4 Force Modulation 1835.4 Image Artifacts 1835.4.1 Tip 1835.4.2 Scanner 1855.4.3 Vibration and Operation 187References 189Further Reading 1896 X-Ray Spectroscopy for Elemental Analysis 1916.1 Features of Characteristic X-Rays 1916.1.1 Types of Characteristic X-Rays 1936.1.1.1 Selection Rules 1936.1.2 Comparison of K, L, and M Series 1946.2 X-Ray Fluorescence Spectrometry 1966.2.1 Wavelength Dispersive Spectroscopy 1996.2.1.1 Analyzing Crystal 2006.2.1.2 Wavelength Dispersive Spectra 2016.2.2 Energy Dispersive Spectroscopy 2036.2.2.1 Detector 2036.2.2.2 Energy Dispersive Spectra 2046.2.2.3 Advances in Energy Dispersive Spectroscopy 2046.2.3 XRF Working Atmosphere and Sample Preparation 2066.3 Energy Dispersive Spectroscopy in Electron Microscopes 2076.3.1 Special Features 2086.3.2 Scanning Modes 2106.4 Qualitative and Quantitative Analysis 2116.4.1 Qualitative Analysis 2116.4.2 Quantitative Analysis 2136.4.2.1 Quantitative Analysis by X-Ray Fluorescence 2146.4.2.2 Fundamental Parameter Method 2156.4.2.3 Quantitative Analysis in Electron Microscopy 216References 219Further Reading 2197 Electron Spectroscopy for Surface Analysis 2217.1 Basic Principles 2217.1.1 X-Ray Photoelectron Spectroscopy 2217.1.2 Auger Electron Spectroscopy 2227.2 Instrumentation 2257.2.1 Ultrahigh Vacuum System 2257.2.2 Source Guns 2277.2.2.1 X-Ray Gun 2277.2.2.2 Electron Gun 2287.2.2.3 Ion Gun 2297.2.3 Electron Energy Analyzers 2297.3 Characteristics of Electron Spectra 2307.3.1 Photoelectron Spectra 2307.3.2 Auger Electron Spectra 2337.4 Qualitative and Quantitative Analysis 2357.4.1 Qualitative Analysis 2357.4.1.1 Peak Identification 2397.4.1.2 Chemical Shifts 2397.4.1.3 Problems with Insulating Materials 2417.4.2 Quantitative Analysis 2467.4.2.1 Peaks and Sensitivity Factors 2467.4.3 Composition Depth Profiling 247References 250Further Reading 2518 Secondary Ion Mass Spectrometry for Surface Analysis 2538.1 Basic Principles 2538.1.1 Secondary Ion Generation 2548.1.2 Dynamic and Static SIMS 2578.2 Instrumentation 2588.2.1 Primary Ion System 2588.2.1.1 Ion Sources 2598.2.1.2 Wien Filter 2628.2.2 Mass Analysis System 2628.2.2.1 Magnetic Sector Analyzer 2638.2.2.2 Quadrupole Mass Analyzer 2648.2.2.3 Time-of-Flight Analyzer 2648.3 Surface Structure Analysis 2668.3.1 Experimental Aspects 2668.3.1.1 Primary Ions 2668.3.1.2 Flood Gun 2668.3.1.3 Sample Handling 2678.3.2 Spectrum Interpretation 2688.3.2.1 Element Identification 2698.4 SIMS Imaging 2728.4.1 Generation of SIMS Images 2748.4.2 Image Quality 2758.5 SIMS Depth Profiling 2758.5.1 Generation of Depth Profiles 2768.5.2 Optimization of Depth Profiling 2768.5.2.1 Primary Beam Energy 2788.5.2.2 Incident Angle of Primary Beam 2788.5.2.3 Analysis Area 279References 2829 Vibrational Spectroscopy for Molecular Analysis 2839.1 Theoretical Background 2839.1.1 Electromagnetic Radiation 2839.1.2 Origin of Molecular Vibrations 2859.1.3 Principles of Vibrational Spectroscopy 2869.1.3.1 Infrared Absorption 2869.1.3.2 Raman Scattering 2879.1.4 Normal Mode of Molecular Vibrations 2899.1.4.1 Number of Normal Vibration Modes 2919.1.4.2 Classification of Normal Vibration Modes 2919.1.5 Infrared and Raman Activity 2929.1.5.1 Infrared Activity 2939.1.5.2 Raman Activity 2959.2 Fourier Transform Infrared Spectroscopy 2979.2.1 Working Principles 2989.2.2 Instrumentation 3009.2.2.1 Infrared Light Source 3009.2.2.2 Beamsplitter 3009.2.2.3 Infrared Detector 3019.2.2.4 Fourier Transform Infrared Spectra 3029.2.3 Examination Techniques 3049.2.3.1 Transmittance 3049.2.3.2 Solid Sample Preparation 3049.2.3.3 Liquid and Gas Sample Preparation 3049.2.3.4 Reflectance 3059.2.4 Fourier Transform Infrared Microspectroscopy 3079.2.4.1 Instrumentation 3079.2.4.2 Applications 3099.3 Raman Microscopy 3109.3.1 Instrumentation 3109.3.1.1 Laser Source 3119.3.1.2 Microscope System 3119.3.1.3 Prefilters 3129.3.1.4 Diffraction Grating 3139.3.1.5 Detector 3149.3.2 Fluorescence Problem 3149.3.3 Raman Imaging 3159.3.4 Applications 3169.3.4.1 Phase Identification 3179.3.4.2 Polymer Identification 3199.3.4.3 Composition Determination 3199.3.4.4 Determination of Residual Strain 3219.3.4.5 Determination of Crystallographic Orientation 3229.4 Interpretation of Vibrational Spectra 3239.4.1 Qualitative Methods 3239.4.1.1 Spectrum Comparison 3239.4.1.2 Identifying Characteristic Bands 3249.4.1.3 Band Intensities 3279.4.2 Quantitative Methods 3279.4.2.1 Quantitative Analysis of Infrared Spectra 3279.4.2.2 Quantitative Analysis of Raman Spectra 330References 331Further Reading 33210 Thermal Analysis 33310.1 Common Characteristics 33310.1.1 Thermal Events 33310.1.1.1 Enthalpy Change 33510.1.2 Instrumentation 33510.1.3 Experimental Parameters 33610.2 Differential Thermal Analysis and Differential Scanning Calorimetry 33710.2.1 Working Principles 33710.2.1.1 Differential Thermal Analysis 33710.2.1.2 Differential Scanning Calorimetry 33810.2.1.3 Temperature-Modulated Differential Scanning Calorimetry 34010.2.2 Experimental Aspects 34210.2.2.1 Sample Requirements 34210.2.2.2 Baseline Determination 34310.2.2.3 Effects of Scanning Rate 34410.2.3 Measurement of Temperature and Enthalpy Change 34510.2.3.1 Transition Temperatures 34510.2.3.2 Measurement of Enthalpy Change 34710.2.3.3 Calibration of Temperature and Enthalpy Change 34810.2.4 Applications 34810.2.4.1 Determination of Heat Capacity 34810.2.4.2 Determination of Phase Transformation and Phase Diagrams 35010.2.4.3 Applications to Polymers 35110.3 Thermogravimetry 35310.3.1 Instrumentation 35410.3.2 Experimental Aspects 35510.3.2.1 Samples 35510.3.2.2 Atmosphere 35610.3.2.3 Temperature Calibration 35810.3.2.4 Heating Rate 35910.3.3 Interpretation of Thermogravimetric Curves 36010.3.3.1 Types of Curves 36010.3.3.2 Temperature Determination 36210.3.4 Applications 362References 365Further Reading 365Index 367