ACTIVITIES

 AVAILABLE SERVICES

 PEOPLE

 CERAMIC PUBLICATIONS

 ULTRASOUND PUBLICATIONS

 ADDRESS

 

 

 

 

ACTIVITIES

 

The Laboratory of Technology of Electronic Materials and Ultrasounds (LTEMU) of the Department of Electrical Engineering (DEE), gives support to the graduation in Electrical Engineering and carries out research work in the following areas:

  Ceramic materials:

    -Study, manufacture and development of ceramics used in electrical and electronic domains. Now, work in the field of sensors, ferrites and solid electrolytes is being developed. Concerning the sensor area, special attention is given to gas sensors. The work developed around this subject is focused in the study and characterisation of conduction phenomena’s in electronic ceramics with the purpose of  using them in the control and detection of gases, gas sensors prototypes production based on bulky or film shaped ceramics (thin and thick films obtained by screen-printing or sputtering) and usage of several other techniques like dopants, additives or filters for improving gas detection parameters.
The main equipment available for this task is a mortar and pestle mill, a centrifugal ball mill, a few high temperature furnaces: 1000, 1300, 1700 and 2300oC, two complex impedance spectroscopes, a gas chromatograph, several gas testing chamber  for ceramic samples and sensor prototypes and a vacuum coating system.

   Head of the group: Professor António José  Ferreira
 

  Ultrasound:

    -Study, development and applications of ultrasound techniques for non-destructive control of materials, such as: surface characterization, defect detection and classification, microstructure characterization (grain sizes), realization of c-scan images in order to detect defects in the material structure; project, manufacture and characterization of ultrasonic probes. The main equipment available for these tasks are a 10-500MHz acoustic microscope (CSAM), c-scan equipment to get ultrasonic images, a complex impedance spectroscope, and a vacuum coating system.

Head of the Group: Professor Jaime B. Santos

 
Co-operation:

    - Pedro Nunes Institute (IPN) and the Institute of the Science and Engineering of Materials and Surfaces (ICEMS). Such collaboration includes the characterization of materials and surface control, didactic and professional formation in the areas of electricity, electronics and sensors and in industry support.

    - Ecole Nationale Supérieures des Mines, Centre SPIN, in gas sensing area.
 

 

AVAILABLE SERVICES

 

   CSAM images of materials at a selectable depth.

  Characterization of materials.

   Characterization of mono and multilayers.

  Characterization of surfaces.

  Thermic treatment of materials.

  Development of ultrasonic sensors.

  Development of quality control systems to use in non-destructive testing.

  Measurement of thin thickness up to 10 m.

  Instrumentation and electronics.

  Electrical and mechanical characterization of ceramic, metallic, polymeric and composite materials.

  Detection of defects and heterogeneity's (porosity's, fissures, inclusions, and delaminations).

  Control of manufacture processes (bonding, adhesions, etc.).

  Control of the component aging.

  Testing of oil of power transformers. These consist of electrical characterization (dielectric rigidity) and chemical characterization (acidity and water contents).

  Electrical isolation of any equipment.

  Formation in the fields of non-destructive control and sensors.

Preparation of ceramic samples (bulky or film shaped ceramics)

Electrical characterisation of the ceramics samples in DC and AC

Samples characterisation under controlled atmospheres

Gas sensor prototypes preparation and testing
 
 

 

PEOPLE

 

 
  Carlos Artur Trindade de Sá Furtado                            (Full Professor)

  António José Ribeiro Ferreira                                        (Associate Professor)

  Jaime Batista dos Santos                                               (Associate Professor)

  Pedro Manuel Gens de Azevedo de Matos Faia           (Assistant Professor)

  Mário João Simões Ferreira dos Santos                        (Assistant Professor)

 

 

CERAMIC PUBLICATIONS

 

     Ferreira, A R ; Furtado, C S ; Perdigão, J M - Grain boundary and bulk electrical resistivities in CoxFe 3-x O4 , Journal of Amer. Ceram Soc. 75:6 (1992) 1708-1711.

     Ferreira, A R ; Furtado, C S ; Perdigão, J M - "Study of the influence of additives on the grain-boundary electrical behavior of ferrites of the CoxFe3-xO4 system", iib92 - 6th International Conference on Intergranular and Interphase Boundaries in Materials, 22-26 Junho, Thessaloniki, Grécia ,1992.

     Ferreira, A R ; Furtado, C S ; Perdigão, J M - Evidência eléctrica da segregação de aditivos para as fronteiras de grão em ferrites do sistema CoxFe3-xO4", Fisica 92, Livro de Resumos, 15-18 Setembro, Vila Real ,1992.

     Certo, J ; Furtado, C S ; Ferreira, A R ; Perdigão, J M - -Fe2O3 Ceramics as negative-temperature coefficient thermistors. Journ. Europ. Ceram. Soc. 11 (1993) 401-405.

     Ferreira, A R ; Furtado, C S ; Perdigão, J M - "Termístores de ferrites de cobalto com tungsténio como aditivo", 3as Jornadas Hispano-Lusas de Ingenieria Eléctrica,Actas do Congresso, Comunicação T59.173, Actas, Tomo IV, pp.1523-1529, 1-3 Julho, Barcelona ,1993.

     Ferreira, A R ; Furtado, C S ; Perdigão, J M - Difusão de cobalto através das fronteiras de grãos em ferrites
     CoxFe3-xO4-um estudo eléctrico", 6o Encontro da S.P.M. - Materiais e Reciclagem, Actas do Congresso, Vol.2, pp. 755-761, 27-29 Outubro, Porto ,1993.

     Ferreira, A R ; Furtado, C S ; Perdigão, J M - Study of the influence of additives on the grain-boundary electrical behaviour of ferrites of the CoxFe3-xO4 system. Materials Science Forum. 126-128 (1993) 769-772.

     Ferreira, A R ; Furtado, C S ; Perdigão, J M - A Study on the diffusion of cobalt atoms in Co0.96Fe2.04O4 ferrites  by means of the variation of grain-boundary impedance, 8th CIMTEC - World Ceramics Congress, B1-L14, pp.66, 28-30 Junho, Florença-Itália ,1994.

     Ferreira, A R ; Furtado, C S ; Perdigão, J M - Energia de activação da resistência eléctrica das fronteiras de grãos de ferrites de cobalto - determinação e estudo da sua variação com a polarização" Fisica 94, Setembro,
Covilhã ,1994.

     Certo, J ; Furtado, C S ; Ferreira, A R ; Perdigão, J M - Studies on densification of-Fe2O3 ceramics. Journal of Materials Science. 30 (1995) 3248-3250.

     Torres, L ; Flores, A ; Zazo, M ; Ferreira, A R ; Furtado, C S ; Perdigão, J M ; Francisco, C ; Rivas, J - Ferromagnetic resonance linewiths of MnCd ferrites: Effect of eddy current processes. Physica Status Solidi.153:1(1996).

        Certo, J. ; Perdigão, J. M. ; Furtado, C. S. ; Ferreira, A. J. - A Pulsed Method for Measuring the Conductivity on Solid Ionic Conductors. J. Europ. Ceram. Soc. 19 (1999) 853-855.

        Certo, J. ; Furtado, C. S. ; Ferreira, A. J. ; Perdigão, J. M. - Na-b-Alumina Powder Processing by a Na2CO3 Precipitation Method. Ionics 4 (1998) 124-128.

        Pedro Faia; Alvaro Nunes; Miguel Pereira; C.S. Furtado - Narizes Electrónicos: uma abordagem diferente às questões de sensibilidade e selectividade. 3as Jornadas ICEMS, Coimbra, 1998.

         Pedro Faia; Alvaro Nunes; Miguel Pereira; C.S. Furtado - Electronic noses, a different approach to the sensitivity and selectivity issues. Electroceramics VI’ 98, Montreaux – Switzerland, 1998.

        Pedro Faia; Alvaro Nunes; Miguel Pereira; C.S. Furtado - Electronic noses, a different approach to the sensitivity and selectivity issues. Journal of European Ceramic Society, vol 19, pp.853-855, 1999.

        Pedro Faia; C.S. Furtado - Sensitivity and selectivity issues of chemical sensing: porosity control”, Smart Structures and Materials. 99, Newport Beach (California) – USA, 1999.

        Pedro Faia; C.S. Furtado; A.R. Ferreira; J.M.Perdigão - Issues on chemical sensing due to porosity control. Electroceramics VII, Portoroz - Eslovénia, 2000.

        Pedro Faia; C.S. Furtado; A.R. Ferreira; J.M.Perdigão - Porosity control: it’s effects on the chemical sensing issues. Second International Conference on Inorganic Materials, Santa Barbara (California) - USA, 2000.

        Pedro Faia; C.S. Furtado; A.R. Ferreira; J.M.Perdigão - Porosity influence on SnO2 oxide ceramics sensitivity to CO. accepted for publication, Materiais 2001, Coimbra.
 

 

ULTRASOUND PUBLICATIONS

 

    J M Perdigão, J B Santos, A R Ferreira, M J Santos, "Sistema de visualização acústico com inclinação e focalização do feixe ultrassonoro controlado por computador", 2as Jornadas Luso-Espanholas de Engenharia Eléctrica, Actas do Congresso, Comunicação 5-17, pp 5.109-5.116, Coimbra, Portugal, 3-5 Julho, (1991).

   Santos, J B ; Perdigão, J M ; Ferreira, A R - "Development of an acoustical visualization system for non destuctive testing of composites" 13th World Conference On Non Destructive Testing, Actas do Congresso, p.1088, Outubro, S. Paulo, Ed. ElsevierScience Pub.,Brasil ,1992.

     J M Perdigão, J B Santos, Ferreira, A R - "Espectroscopia ultrassonora na caracterização e detecção de defeitos em materiais", Fisica 92, Livro de Resumos, 15-18 Setembro, Vila Real ,1992.

     Santos, J B ; Perdigão, J M - "Artificial neural Networks for defects classification using ultrasonic signals", RECPAD'93 5th Portuguese Conference on Pattern Recognition, Conference Proceedings, pp.17-22, 13-14 Maio, Porto,1993.

     Santos, J B ; Perdigão, J M - "Automatic defects classification system using spectral analysis and neural networks", Ultrasonics International 93 Conference Proceedings, pp.763-766, Julho, Austria ,1993.

     Perdigão, J M ; Santos, J B ; Ferreira, A R - "Microscopia ultrassonora no contrôlo de materiais e degradação de superfícies", 6o Encontro da S.P.M. - Materiais e Reciclagem , Actas do Congresso, Vol.1, pp.471-477, 27-29, Outubro, Porto ,1993.

     Santos, J B ; Perdigão, J M - Amplitude transfer function technique for defects classification. Ultrasonics. 32:4 (1994), 287-292.

     Santos, J B ; Perdigão, J M - " Corrosion detection using the transfer function technique in the frequency
domain", Proceedings of ASNT's 1994 Spring Conference, pp.31-33, 21-25 Março, USA ,1994.

     Santos, J B ; Perdigão, J M - " Quality ultrasonic testing of bonded structures by spectral analysis", Proceedings of First Joint Belgian-Hellenic Conference on Non Destructive Testing, pp. 22-23 Maio, Patras, Grécia ,1995.

    M J Santos, J. Santos, J. M. Perdigão, "Microstructure characterization of ?-Fe2O3 ceramics by ultrasound", WCU97- Ultrasonics World Congress, pp. 326-327, Yokohama, Japão, 24-27 Agosto, (1997).

    N Fernandes, M J Santos, J B Santos, A R Ferreira, J M Perdigão, J Velho, C Gomes, “Quartezites Behaviour Under Oceanic Environment: Physical Characterization Using Ultrasound Propagation and Aging”, Materials in Oceanic Environment, Vol.I, pp.403-410, Ed. L. Faria, EUROMAT´98, Lisboa, Portugal, Junho (1998).

    N Fernandes, M J Santos, A R Ferreira, J M Perdigão, “ Mechanical and Structural Characterization of Concrete by Ultrasound”, XII Congress on Ready Mixed Concrete Organisation, Vol.II, pp.940-948, ERMCO´98, Lisboa, Portugal, Julho, (1998).

    J Velho, C Gomes, N Fernandes, M J Santos, A R Ferreira, J M Perdigão, “Caracterização físico-quimica e ultrassónica de rochas carbonatadas”, 5º Congresso de Geologia, Lisboa, Portugal, Novembro (1998).

     M J Santos, A R Ferreira, N Fernandes, J M Perdigão, “Ultrasonic Characterization of Roughness Surface”, Acústica 98 - Congresso Ibérico de Acústica, Vol.I, pp.633-636, Lisboa, Portugal, 14-16 Setembro, (1998).

     M J Santos, A R Ferreira, N Fernandes, J M Perdigão, J Velho, C Gomes, “Ultrasonic Control of Quartizites: Anisotropic Behaviour Interpretation”, Sessão D – Characterization of Material Proprieties, UI/WCU99, Ultrasonic International ‘99/ 1999 World Congress on Ultrasonic, Technical University of Denmark, Copenhaga, Dinamarca, 29 Junho-1 Julho, (1999).

    A R Ferreira, M J Santos, N Fernandes, J M Perdigão, J Velho, “Ultrasonic Control of Quartizites: Attenuation and Velocities Discrepancies Interpretation”, Materials Evaluation, (aceite em Julho de 2000, aguarda publicação).

     M J Santos, A R Ferreira, , N Fernandes, J M Perdigão, “Detection and Classification of Defects in Thin Structures Using Lamb Waves”, Acústica 2000 – II Congresso Iberoamericano de Acústica, Madrid, Espanha, 16-18 Outubro, (2000).
 

 

ADDRESS

 

Departamento de Engenharia Electrotécnica e Computadores

Pólo II, Pinhal de Marrocos

3030 Coimbra

Portugal

Tel. 351.239.796214
Fax 351.239.796247
 

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