CHEMISTRY AND TECHNOLOGY OF GLASSES
Learning outcomes of the course unit
It is required an adequate understanding that can be based on the scientific background acquired in the first study cycle to extend their skills and to apply new processing approaches
The student is expected to be able to:
- correctly describe what is a glassy material also about the experimental techniques underlying the characterization of an amorphous.
-knowing how to describe the most used plants in the glass industry with reference to the various production phases also in relation to what was observed during the visits at the plants.
- Knowing the main chemical compositions for the glassy materials described in the course. (Knowledge and understanding capacity)
- identify the procedures useful for the modification of mechanical, optical and physical properties of glass materials.
-know how to monitor the variation of physical properties as a function of the glass composition. (ability to apply knowledge and understanding)
- tackle the issues in a multidisciplinary manner with particular attention to the relationship between composition, production techniques and physical, chemical and mechanical properties of inorganic glass is required.
- update the themes through the consultation of scientific publications specific to the sector. (Autonomy of judgment).
- clearly communicate the topics covered during the course and to be able to correlate the various topics.
-knowing how to properly use the appropriate terminology and demonstrate how to interact with other professionals. (Communication skills)
- update their knowledge by consulting the scientific and technical production and knowing how to exploit the information contained in patents.
- keep up-to-date and know critically to judge the information contained in scientific publications and technical reports (Learning skills)
Course contents summary
Crystallization and glass transition. glass definition. glass transition Tg. Thermodynamic parameters of the glass transition. Transitions of the second order; definition of the glass structure, theoretical models. Parameter of Goldsmidth, Model of Zachariesen, Q parameter and connectivity. Theory of Dietzel, Lebedev model, boron glass (structural anomalies in the properties).
Crystallization in the glass; homogeneous, heterogeneous and epitaxial growth. Nucleation and growth rate of crystallization, the Tamman diagram. Kinetics of formation of TTT diagrams glasses.
Liquid-liquid immiscibility. Models of Bernal, Frenkel and Stewards, termodinamics of spinodal decomposition, binodale mode of immiscibility. Comparison between spinodal decomposition and nucleation. Phase diagrams (Na2O CaO-SiO2-Na2O-SiO2 and others)
Vycor glass. Glass production methods: sol-gel and melt synthesis: raw materials, gravimetric factor, solid state reactions, decomposition, fining agents. coloring agents SCHOTT catalogue. Industrial processes for the production of glass products. different types of furnaces and melting and refining stages. forming and annealing processes. Defects in glassy products; ropes, bubbles, crystalline inclusions, Glass ceramics; controlled crystallization, pyroceram, Macor, glass-ceramic applications.
Properties of glasses. Pseudoelestico viscosity behavior, equation of Vogel-Fulcher-Tamman. Dependence on the viscosity by temp. and its technological relevance. Viscosity and composition. Methods to determine the viscosity. Thermal expansion of Winkelman-Schott model. density of glass
electrical properties, and ionic conductivity dependence on composition.
Mechanical properties of surface cracks glass, analysis of cracks for chemical bath, Young's modulus, thermal and chemical processes of tempering. Optical properties of the silica glass, the transmission spectrum. Refractive index and its dependence on composition. molar rifrectivity, reflection, dispersion. chromatic aberration, Abbe Number, flint and crown glass. Refractometer V-block. Opals
Chalcogenide glasses, structure, composition, synthesis processes, applications and properties.
Optical fibers, different types of optical fibers, production techniques. Bioactive glasses, glassware 45S5. Metal glasses, mechanical properties, critical parameters for glass production.
Introduction to Glass Science and Technology. by J. E. Shelby
Royal Society of Chemistry
Fundamentals of Inorganic Glasses
Author: Arun Varshneya
The lessons will be carried out by illustrating the concepts summarized in slides. Films will be screened to make some of the steps in the industrial production of glass products clearer. An experience will be organized in the laboratory where the process of fusion by scrap will be shown. Educational visits are planned at glass factories and research institutes where it is possible to see systems for the production of unconventional glass materials. Seminars by experts in the production cycle of traditional glass materials are also possible. The slides will be available at the ELLY portal.
Assessment methods and criteria
The assessment procedure consists of an oral test which consists of two main phases: the first is the presentation of a topic chosen by the student. The topic can be any one of the various chapters of the course (from the theory to the more applicative) and the presentation can be based only on the material provided on ELLY. Otherwise it is the student's right to deepen the subject with additional material that can be found with a bibliographic research. This last indication is not mandatory but it is the student's faculty to bring further elements of study.
In the second phase the teacher will ask questions about the rest of the program to verify the knowledge of the different aspects of the chemistry and technology of vitreous materials with exploration of the skills acquired both for the theoretical part and for the technological part. The evaluation will be also focused to the candidate's ability to present the topics using the correct terminology and to be able to get specific knowledge independently.