Techniques of Characterization and Nondestructive Testing

General characterization

Prerequisites

There are no disciplines required prior to enrollment in this course. However it is assumed that student have general knowledge of mathematics and physics.

Bibliography

Microscopia Óptica, Rui Silva, cópia da apresentação realizada pelo docente nas aulas teóricas.

Microstructural Characterization of Materials, David D. Brandon, Wayne D. Kaplan, Wiley-VCHI

“Scanning Electron Microscopy and X-ray Microanalysis”, J. I. Godstein et al, second edition, Plenum Press, New York (1992).

“Microscopia Electrónica de Varrimento - Textos de apoio”, Rui Silva, FCT-UNL, 2006.

Ensaios não destrutivos, F. P. Almeida, J. Barata e P. Barros, ISQ Edições Técnicas

Non Destructive Testing, R. Halmshaw, 2nd edition, Edward Arnold

Elements of X-ray Diffraction, B.D. Cullity, 1978

Modern Powder Diffraction, edt. D. Bish & J. Post, Min. Soc. Amer., 1989

Teaching method

Theoretical classes with datashow.

Problem solving classes with student participation.

Practicals include theory preparation, experimental procedure and production of a report.

Availability of the study material in the internet.

Evaluation method

For the continuous evaluation is compulsory of  tests, one for each module, and the presence at the practicals.

The final mark is computed weighting the mark of each module according to the weeks taken for its lectures. DRX/FRX- 2; MO/SEM 4; END 4; Espectroscopias 3.

To PASS one must reach 10 marks.

Subject matter

OPTICAL MICROSCOPY MODULE
Light. Visible light spectrum and colors. Laws of refraction, reflection and diffraction of light.. Main types of optical microscopes, transmission and reflected microscopes. Basics and main components of an optical light microscope. Convex and concave lenses, the focal length and ray diagrams of a lens. Image of an object. Definition of image resolution and magnification. Optical aberrations of lens. Magnification, numerical aperture and resolving power of a single lens.  Illumination system. Optical components: condenser, eyepieces and  objective lens. Types of objective lenses (achromat, fluorite or semiapochromat and apochromat lens). Magnification, numerical aperture, and resolving power of objectives lenses. Depth of field. Immersion lenses. Aperture and field diaphragms. Cameras and digital image. Contrast methods in light microscopy: bright field, oblique illumination, dark field, Rheinberg contrast, polarized light, phase contrast and differential interference contrast (DIC). Fluorescence microscopy. Contrast imaging methods and optical microscopes used in materials science and engineering.

SPECTROSCOPY MODULE
Infrared spectroscopy; Transmission spectroscopy in the near IR, visible, and UV range; Spectroscopic ellipsometry. Characterization of thin films of amorphous silicon and zinc oxide, using these techniques for the determination of the film's thickness, composition, optical properties (refractive index, optical gap, absorption coefficient, etc..)

ELECTRONIC MICROSCOPY MODULE
Accelerated electron beam versus light beam, advantages and disadvantages of electron microscopy. Main types of electron  microscopes, transmission (TEM), scanning electron microscopes (SEM) and transmission scanning (STEM) microscopes. Image of an object in a TEM and SEM. Resolution and magnification in SEM and TEM. Depth of field in SEM. Sample preparation in SEM and TEM.
Main emission, electron-matter interactions, used in SEM. Backscattered electrons, secondary electrons. Characteristics and continuous X-ray emissions. Interaction volumes of emissions and typical resolutions.
Main and auxiliary components of a SEM. Electron guns: tungsten filament and field emission guns. Influence of electron gun type in final spot size and resolution. Electromagnetic lenses and diaphragms. Electron detectors and modes of operation. X-ray detectors (EDS and WDS spectrometers). Importance of the vacuum and anti-vibration pneumatic systems.
Image contrast methods used in SEM: topographic and number atomic contrast.. Elemental analysis and x-ray mapping in SEM-EDS/WDS.

NON-DESTRUCTIVE TESTING MODULE
Objectives of Non-Destructive Testing. Radiological Methods. General principles. Build-up image factor. X-rays, Gamma rays and their sources. The Coolidge tube and radioactive materials. Control parameters in a radiological test. Units. Radiation absorption. Mechanisms of absorption and dispersion. Radiation recording. Contrast and gradient of a film. Radiographic technique and sources of unsharpness. Image Quality Indicators. Aplications and result interpretation.
Ultrasonic Tests. Types of waves in solids. Sound velocities in selected materials. Waves in an interface. Important cases. Oblique incidence and the Snell law. General case and mode conversion. Ultrasound attenuation. Generation of ultrasound waves: transversal and longitudinal probes. Scanning modes and calibration blocks.
Magnetoscopy. Basic principles. Advantages and disadvantages. Magnetising techniques. AC and DC techniques. Magnetic inks and powders. Viewing. Sensitivity. Demagnetization.
Penetrant Flaw detection. Principles. Techniques. Systems. Pre-cleaning and cleaning. Practical procedure. Types of liquids and their sensitivity. Viewing. Recording.

TECHNIQUES BASED ON X-RAYS
The physics of X-ray radiation. The electromagnetic spectrum. Interaction of x-rays with matter: absorption and photoelectric effect. Fluorescence radiation. Coherent and inelastic dispersion. Polarization.
X-ray detection. Emission and absorption spectra from an element. Short reference to the application of x-ray fluorescence in chemical analysis. X-ray diffraction. Bragg law. Systematic extinctions and diffracted intensities (physical and geometrical factors).
X-ray diffraction by polycrystalline materials. Powder diffractometry: Bragg-Brentano geometry. Glazing incidence. Short reference to diffraction by mono-crystals. Degre of crystallinity. The effect of texture and residual stresses upon diffracted intensities.

Programs

Programs where the course is taught: