This book documents the efforts towards thermal characterization of templated nanostructures using an infrared (IR) thermography based non-contact technique. One dimensional bismuth telluride Bi2Te3 nanostructures were grown using anodic alumina (AAO) template assisted electrodeposition technique. An infrared thermography based technique was then developed for the in-plane thermal diffusivity measurements of these templated nanocomposites. The thermal diffusivity of the nanowires alone was estimated through comparing the experimental results with the predictions made by a first order lower bound model (FOLBM). A mathematical background of the proposed technique with simulation studies is also reported.
Infrared thermography techniques are widely used for non destructive testing (NDT) and evaluation. The application areas are greatly varied: from water entrapment and moisture evaluation of buildings, degradation of EPROM (erasable programmable read only memory) chips and printed circuit boards, defect detection and characterization in turbine blades, medical and veterinary applications such as thermal coronary angiography, humane breast tumors, neuromuscular disorders, public services as forest fire detection and monitoring of traffic roads, to name a few.
Table of Contents
Chapter 1 Infrared thermography and nanomaterials: a review
1.1 Introduction to infrared thermography
1.2 Infrared thermography in thermal characterization
1.3 Thermography at reduced dimensions
1.4 Anodic alumina (AAO) templated nanostructures
1.5 Thermoelectrics
1.6 Bismuth telluride (Bi2Te3) nanowires
1.7 Motivation and objectives of the thesis
1.8 Thesis overview
1.9 References
Chapter 2 Synthesis and physical characterization of bismuth telluride nanowires
2.1 Bi2Te3: one dimensional nanostructure
2.2 Electrodeposition of Bi2Te3 nanowires
2.2.1 Electrolyte preparation
2.2.2 Working electrode preparation
2.2.3 Electrodeposition process
2.3 Physical characterization
2.3.1 X ray diffraction study (XRD)
2.3.2 Energy dispersive X-ray study (EDX)
2.3.3 Scanning electron microscopy (SEM)
2.3.4 Transmission electron microscopy (TEM)
2.4 Aging of Bi2Te3 nanowires
2.5 Single crystal bulk Bi2Te3
2.6 Conclusions
2.7 References
Chapter 3 Modeling, analysis and simulation of thermal waves in template nanomaterials
3.1 Introduction
3.2 AAO template thermal response
3.3 Periodic point source heating
3.4 Thermal diffusivity measurement
3.5 IR experiment with empty AAO template
3.6 Simulation studies
3.6.1 Electro-thermal mode
3.6.2 thermo SIM: software for thermal simulation
3.6.3 Phase image and phase image slope
3.6.4 Influence of convection and radiation effects
3.7 Experimental verification of convection effect
3.8 Conclusions
3.9 References
Chapter 4 Thermal characterization using infrared thermography
4.1 Thermal characterization techniques
4.1.1 Laser flash method
4.1.2 The 3-Omega method
4.1.3 Photo thermoelectric method
4.2 Infrared thermography system
4.2.1 Classification of IR thermography techniques
4.2.2 Infrared detectors and cameras
4.3 Lock-in thermography for thermal characterization
4.3.1 Phase and Amplitude images
4.3.2 Principle of operation
4.3.3 Experimental details
4.3.4 Data analysis and interpretation
4.4 Anisotropic AAO thermal diffusivities
4.4.1 In-plane thermal diffusivity of AAO template
4.5 Thermal diffusivity of single crystal Bi2Te3 sample
4.6 Thermal diffusivity of AAO/Bi2Te3 nanocomposite
4.7 Error analysis
4.8 First order lower bound model (FOLBM)
4.9 Thermal diffusivity of Bi2Te3 nanowires
4.10 Thermal diffusivity of AAO/Ni, Co nanocomposites
4.11 Conclusions
4.12 References
Chapter 5 Frequency modulated thermal wave imaging for thermal diffusivity measurements
5.1 Introduction
5.2 Fundamentals of FMTWI
5.3 FMTWI for thermal characterization
5.4 Thermal diffusivity of empty AAO template
5.4.1 Experimental details
5.4.2FMTWI response in time and frequency domain
5.4.3Extraction of multiple phase and amplitude image
5.5 Thermal diffusivity estimation
5.5.1Phase slope measurement
5.5.2Thermal diffusivity calculation
5.6 FMTWI Time bandwidth influence
5.6.1 FMTWI: 2 second period & 1 - 3 Hz bandwidth
5.6.2 FMTWI: 5 second period & 1 - 3 Hz bandwidth
5.6.3 FMTWI: 5 second period & 0.5 - 1.5 Hz bandwidth
5.7 Conclusions
5.8 References
Chapter 6 Conclusions and future directions
6.1 Conclusions
6.2 Future directions
Research Objective and Topics
The primary research objective is to develop and implement non-contact infrared (IR) thermography-based techniques for the accurate in-plane thermal diffusivity measurement of anodic alumina (AAO) templated nanostructures, specifically focusing on bismuth telluride (Bi2Te3) nanowires. The study aims to overcome the limitations of traditional contact-based thermal characterization methods, which are difficult to apply to delicate nanoscale materials, by utilizing active lock-in thermography and frequency-modulated thermal wave imaging (FMTWI) to extract reliable thermal parameters while mitigating issues like convective and radiative heat losses.
- Thermal characterization of one-dimensional nanostructures using non-contact IR thermography.
- Synthesis and optimization of Bi2Te3 nanowires via AAO template-assisted electrodeposition.
- Development of electro-thermal models and simulation tools for thermal wave analysis.
- Comparative analysis of thermal diffusivity in bulk materials vs. templated nanocomposites.
- Implementation of Frequency Modulated Thermal Wave Imaging (FMTWI) for enhanced measurement efficiency.
Excerpt from the Book
1.1 Introduction to infrared thermography
Thermography was initially developed to image temperature distributions, generally at a distance and through the air. Thermography literally means „writing with heat‟, similar to optical photography which means „writing with light‟. Infrared (IR) thermography may further be defined as the thermal study of an object surface through monitoring its emitted IR radiations. The invisible infrared radiations emitted from the surface of an object can be detected using suitable sensors and are represented as thermal images or thermograms.
The principle of operation of IR thermography is based on Planck‟s law and Stefan-Boltzmann law [1]. Every physical body having a finite temperature above absolute zero, continuously emits electromagnetic radiation. Planck‟s law describes the distribution of this emitted radiation as a function of the wavelength at a given temperature, which for a perfect black body may be expressed as,
E (λ,T) = (2hc^2) / (λ^5 [exp(hc / λKBT) - 1]) ………………….(1.1)
where E is the spectral radiance, T is the absolute temperature, KB is the Boltzmann constant, h is the Planck constant, and c is the speed of light. It may be further stated that for a given temperature the amplitude of the emitted radiation varies with the wavelength.
Summary of Chapters
Chapter 1 Infrared thermography and nanomaterials: a review: This chapter provides an introduction to infrared thermography and its application in nanomaterials research, covering theoretical foundations and the current state of measurement technology.
Chapter 2 Synthesis and physical characterization of bismuth telluride nanowires: This chapter details the electrodeposition synthesis of Bi2Te3 nanowires within AAO templates and examines their structural properties using various imaging and analytical techniques.
Chapter 3 Modeling, analysis and simulation of thermal waves in template nanomaterials: This chapter establishes the theoretical and mathematical background for thermal wave propagation, including the development of an electro-thermal simulation model.
Chapter 4 Thermal characterization using infrared thermography: This chapter introduces the lock-in thermography technique for experimental thermal diffusivity measurement and validates it against established models and materials.
Chapter 5 Frequency modulated thermal wave imaging for thermal diffusivity measurements: This chapter introduces the FMTWI technique as an efficient alternative to conventional lock-in thermography, utilizing chirp excitation to accelerate the measurement process.
Chapter 6 Conclusions and future directions: This chapter provides a final overview of the research contributions and suggests potential avenues for future experimental improvements and applications.
Key Words
Infrared thermography, Bismuth telluride, Bi2Te3, AAO template, Thermal diffusivity, Nanowires, Lock-in thermography, Frequency modulated thermal wave imaging, FMTWI, Electrodeposition, Nanomaterials, Thermal characterization, Heat transfer, Thermal waves, First order lower bound model
Frequently Asked Questions
What is the core focus of this research?
The research focuses on the development of non-contact infrared thermography-based techniques to measure the in-plane thermal diffusivity of one-dimensional nanostructures, specifically bismuth telluride nanowires embedded in anodic alumina (AAO) templates.
What are the primary fields of study included in this work?
The study spans the fields of nanotechnology, thermal physics, material characterization, and electrochemistry, with a specific focus on thermoelectric materials and non-destructive testing (NDT) methodologies.
What is the ultimate goal of the thesis?
The primary goal is to provide a reliable, efficient, and non-contact methodology for assessing the thermal properties of delicate nanostructures, enabling a better understanding of how reduced dimensions affect thermal transport compared to bulk counterparts.
Which specific scientific methods are utilized?
The research employs active lock-in thermography and the newer Frequency Modulated Thermal Wave Imaging (FMTWI) technique, supported by mathematical electro-thermal modeling and simulation to verify experimental findings.
What topics are discussed in the main body of the work?
The work covers the synthesis of bismuth telluride nanowires via electrodeposition, characterization of their physical properties (XRD, SEM, TEM), mathematical modeling of thermal waves, and experimental thermal diffusivity measurements using lock-in and frequency-modulated imaging techniques.
Which key terms define this work?
Key terms include infrared thermography, bismuth telluride (Bi2Te3), thermal diffusivity, AAO templates, nanowires, lock-in thermography, and frequency modulated thermal wave imaging (FMTWI).
Why is the aging effect of Bi2Te3 nanowires significant?
The aging effect, which involves the formation of thin oxide layers (Bi2O3 and TeO2) upon exposure to the atmosphere, significantly degrades the thermoelectric figure of merit and makes stable electrical contact difficult, motivating the development of non-contact characterization techniques while the nanowires are still shielded within the AAO matrix.
How does the FMTWI technique improve upon conventional methods?
FMTWI reduces total experimental operational time by using a frequency-modulated chirp signal, allowing for the extraction of multiple phase and amplitude information from a single experimental run, unlike traditional lock-in methods that require separate tests at individual frequencies.
- Citar trabajo
- Khalid Muzaffar (Autor), 2014, Infrared Thermography. Thermal Diffusivity Measurements of Templated Nanomaterials, Múnich, GRIN Verlag, https://www.grin.com/document/461825
