Cinética No Processamento Avançado de Sólidos › 45480

[COURSE LECTURED IN ENGLISH]

The main objectives of the course on Kinetics in Advanced Processing of Solids  are:

- to improve literature review skills, with emphasis on solid state kinetics and its relevance to materials processing;

- to identify kinetic limitations with her/his research projects;

- to select experimental techniques or other suitable methods for those studies;

- to get independent training on quantitative methods of kinetic analysis.

On attending this course on kinetics in advanced materials processing and reaching a positive assessment the doctoral candidates shall have demonstrated;

-  Advanced understanding of solid state kinetics, and correlations between its models and methods;

-  Literature reviewing of relevant solid state kinetic processes;

- Skills for oral presentations and public discussion of scientific work;

-  Suitable knowledge about dedicated experimental techniques and other methods, with emphasis on methods available at the University of Aveiro or readily available at other institutions in Portugal, including their detailed location and responsible/contact persons.

-   Ability to identify techniques or methods for specific solid state kinetics processes,Training with, at least, one quantitative method, including selecting of suitable operation conditions or other input parameters, treatment of results and their discussion.

Contents

 Learning Unit 1: Solid State kinetics

Short review of defect chemistry, with emphasis on the dependence on composition and working conditions

Role of defects on diffusion and their impact on solid state reactions

Thermodynamic constrains and guidelines for reactivity of solids

Size effects on solid state kinetics

Topochemical effects on solid state kinetics

Principles and applicability of kinetic models

      Models for isokinetic isothermal conditions,

     Models for variable temperature (diffusion, solid state reactions, phase transformations)

    Universal models for generic thermal cycles: relations between kinetic parameters for models with constant and variable temperature

    Kinetic models for processes occurring close to equilibrium

    Models for processes with competing or concurrent steps (sintering, crystallization) 

Learning Unit 2 - (Elective) . Kinetics in representative materials processing methods

This learning unit will be mainly based on one may elective topic, closely related to the student´s research interests. Representative topics will be:

Powder processing:

    High T processes (decomposition of solid reactants, solid state reactions,..)

    Low T processes (mechanosynthesis, etc.)

Sintering:

    Revision of sintering mechanisms

    Less common sintering methods (fast firing, 2-step sintering, spark plasma sintering, microwave sintering,…)

Phase transformations

Glass crystallization

Materials modifications by frozen-in defect chemistry:

    Bulk defect changes, space charge effects at internal or external interfaces, etc.

Degradation of materials:

    oxidation of materials or interactions with gases,

    thermal degradation, etc.)

Learning Unit 3 - Elective: Quantitative methods in solid state kinetics.

This learning unit will also be mainly based on a single technique, according to the student´s research interests.

Thermoanalytical real time methods:

    Dilatometry

    Differential thermal analysis and calorimetry

    Thermogravimetry

     Less common methods: electrical or electrochemical methods (conductivity relaxation, impedance spectroscopy with variable T, coulometric titration,…)

Post-morten analyses:

      Macroscopic changes (weight, volume changes, …)

      Microscopy and stereology

      “Quantitative” XRD

      “Quantitative” spectroscopies (Infrared, Mossbauer, etc.)

 Training: Training may be based on experimental (mainly thermoanalytical) or other methods (e.g. computational) and will address a relevant issue within the candidate´s workprogram or a relevant study case, identified in the literature.

The assessment will be based on the following items:

(i) Written appraisal (1-3 pages) and 15 min oral presentation of relevant contents and/or limitations of one relevant scientific article addressing methods or a relevant study case of solid state kinetics.

(ii) Written document (1-2 pages) identifying kinetic issues within her/his workprogram or closely related future work, and suitable methods. The candidate´s supervisor will also participate in the assessment of this written report.

(iii) Written report on training activities, containing identification of objectives, experimental conditions, treatment of raw data and their interpretation, including a comprehensive discussion of best results and failed attempts.

The candidate´s supervisor will participate in the assessment of written reports mentioned in (i), (ii) and (iii)Oral presentation skills will be assessed by peers (other fellow PhD candidates).

It is assumed that every PhD student registered for the Doctoral Program will have suitable academic education to be able to attend this course on kinetics of advanced materials processing. Other students registered for different Doctoral Programs should have attended, at least, one introductory course on solid state chemistry, solid state physics, or corresponding contents.

Teaching comprises the following combined contributions:

i) theoretical analysis of:  fundamentals of solid state kinetics,  kinetic models to describe the roles of relevant variables, with emphasis on thermal history,    revision of materials processing operations with kinetic constraints or susceptible of optimization by controlling their kinetics,    Principles, advantages and limitations of relevant thermoanalytical methods, including cost and availability, as well as safety, health and/or environmental risks;

ii) Guided literature reviews to develop improved skills for the interpretation of scientific articles and self learning;

iii) Identification, by the PhD candidate, of kinetic issues within her/his work program and corresponding prospective research methods;

iv) Training based on selected methods (thermoanalytical, computational, etc.) preferentially addressing issues related to her/his work program, or a suitable study case closely related to personal research interests.

Bibliography

            The main literature includes well established textbooks on solid state kinetics and a selection of scientific articles addressing a variety of kinetic problems in materials science and engineering. These will be updated for every editions of the doctoral program.  

Textbook: H. Schmalzried: Chemical Kinetics of Solids, VCH, 1995

 Selection of scientific articles

D.H.Park et al., Solid State Ionics, 172 (2004) 413-4

M.H.Lin, J.F.Chou, H.Y.Lu, “The rate determining mechanism in the sintering of undoped nonstoichiometric baroum titanate”, J. Eur. Ceram. Soc., 20 (2000) 517-26 (defect chemistry, nonstoichiometry)

F.J.Gotor, J.M.Criado, J.Malek, N.Koga, “Kinetic analysis of solid state reactions: The universality of master plots for analyzing isothermal and nonisothermal experiments”, J.Phys. Chem.,A, 104 (2000) 10777-82 Solid State Reactions

P.Budrugeac et E.Segal, “Some methodological problems concerning nonisothermal kinetic analysis of heterogeneous solid-gas reactions”,

S.Vyazovkin, Thermal analysis”, Anal. Chem., 74 (2002) 2749-62

S.L.Simon, “Temperature modulated differential scanning calorimetry: theory and application”, Thermochimica Acta, 374 (2001) 55-71