Tribological behavior of silicon textured with LIPSS was compared to polished Si. • The friction ... more Tribological behavior of silicon textured with LIPSS was compared to polished Si. • The friction coefficient is larger for the textured specimens. • Plastic deformation contribution to friction is larger for textured specimens. • The friction coefficient is larger when sliding in the perpendicular direction. • Thicker tribolayer formation and higher flash temperatures explain the difference.
The electrochemical performance of electrodes for solid oxide fuel cells (SOFC) requires porous s... more The electrochemical performance of electrodes for solid oxide fuel cells (SOFC) requires porous structures with a large number of active triple phase boundaries. Further improvements require the development of new oxygen electrodes with highly porous structures able to enhance the adsorption process and provide high active zones for oxygen reduction. However, a high level of porosity leads to low mechanical properties that may compromise the electrodes integrity and cell performance that must be studied. This work investigates the mechanical properties and behavior of CGO-LSCF composite coatings developed by electrostatic spray deposition as oxygen electrodes for intermediate temperature SOFC. The coatings are characterized by a highly porous coral-like structure formed of aggregate nanoparticles that result in a very high surface area. Their mechanical behavior was studied by nanoscratch and nanoindentation tests and a model of material degradation under progressive compressive loa...
2020 IEEE International Conference on Plasma Science (ICOPS), 2020
One of the grand challenges in the carbon-based nanomaterials research lies in the complexity and... more One of the grand challenges in the carbon-based nanomaterials research lies in the complexity and sensitivity of the synthesis processes. Plasmas are an alternative and sustainable strategy to synthesize disruptive nanostructures since they allow the effective control over the nucleation and assembling mechanisms at atomic scale level.
Objectivos: estudar a resistência adesiva entre o titâ- nio puro e dois tipos de cerâmica dentári... more Objectivos: estudar a resistência adesiva entre o titâ- nio puro e dois tipos de cerâmica dentária. Materiais e métodos: Foram realizados ensaios de flexão em 3 pontos a amostras metal/cerâmica, obten- do-se a resistência adesiva dos sistemas utilizados, de acordo com a norma ISO 9693-1999. Constituíram-se 6 grupos. Os grupos de ensaio foram fabricados a partir detitânio (Ti- grau 2) e duas cerâmicas: uma feldspática (IPS-Design) e outra indicada para a utilização com titânio (TRI-Triceram). Constituíram-se quatro grupos de controlo combinando ligas de CrCo e de AuPd com as duas cerâ- micas mencionadas anteriormente (TRI e IPS). As amos- tras foram analizadas posteriormente por Microscopia Electrónica de Varrimento (SEM/EDS) de forma a identificar o tipo de falha de união. Resultados: Dos seis grupos testados, unicamente o grupo Ti/IPS apresentou valores de resistência adesiva (18.09 ± 7.3 MPa) abaixo dos mínimos indicados na norma ISO (25 MPa). A caracterização do tipo de falha de ...
Laser surface alloying processes all the features of surface melting, plus additional capability ... more Laser surface alloying processes all the features of surface melting, plus additional capability of modifying the chemical composition by adding alloying elements which greatly enhance the wear and corrosion resistance of aluminium alloys. This paper is concerned with a study of the formation mechanism and structural changes of the alloyed layer during laser surface alloying aluminium with niobium...The material is
V. Livramento 1, a , MT Marques 1, b , JB Correia 1, c , A. Almeida 2, d , R. Vilar 2, e ... 1INE... more V. Livramento 1, a , MT Marques 1, b , JB Correia 1, c , A. Almeida 2, d , R. Vilar 2, e ... 1INETI-DMTP, Estrada do Paço do Lumiar, 22, 1649-038 LISBOA, Portugal; 2IST-Dep. Eng. de Materiais, Av. Rovisco Pais, 1049-001 Lisboa, Portugal ... Keywords: mechanical ...
422 Electrochemical Methods in Corrosion Research V minimise oxidation during LSM, argon gas was ... more 422 Electrochemical Methods in Corrosion Research V minimise oxidation during LSM, argon gas was blown over the molten pool. Table 1 - Nominal composition of 2024 aluminium alloy %Cu %Mg %Mn %A1 4.4 1.5 0.6 bal 7175-T7351 aluminium alloy plate with nominal ...
Tribological behavior of silicon textured with LIPSS was compared to polished Si. • The friction ... more Tribological behavior of silicon textured with LIPSS was compared to polished Si. • The friction coefficient is larger for the textured specimens. • Plastic deformation contribution to friction is larger for textured specimens. • The friction coefficient is larger when sliding in the perpendicular direction. • Thicker tribolayer formation and higher flash temperatures explain the difference.
The electrochemical performance of electrodes for solid oxide fuel cells (SOFC) requires porous s... more The electrochemical performance of electrodes for solid oxide fuel cells (SOFC) requires porous structures with a large number of active triple phase boundaries. Further improvements require the development of new oxygen electrodes with highly porous structures able to enhance the adsorption process and provide high active zones for oxygen reduction. However, a high level of porosity leads to low mechanical properties that may compromise the electrodes integrity and cell performance that must be studied. This work investigates the mechanical properties and behavior of CGO-LSCF composite coatings developed by electrostatic spray deposition as oxygen electrodes for intermediate temperature SOFC. The coatings are characterized by a highly porous coral-like structure formed of aggregate nanoparticles that result in a very high surface area. Their mechanical behavior was studied by nanoscratch and nanoindentation tests and a model of material degradation under progressive compressive loa...
2020 IEEE International Conference on Plasma Science (ICOPS), 2020
One of the grand challenges in the carbon-based nanomaterials research lies in the complexity and... more One of the grand challenges in the carbon-based nanomaterials research lies in the complexity and sensitivity of the synthesis processes. Plasmas are an alternative and sustainable strategy to synthesize disruptive nanostructures since they allow the effective control over the nucleation and assembling mechanisms at atomic scale level.
Objectivos: estudar a resistência adesiva entre o titâ- nio puro e dois tipos de cerâmica dentári... more Objectivos: estudar a resistência adesiva entre o titâ- nio puro e dois tipos de cerâmica dentária. Materiais e métodos: Foram realizados ensaios de flexão em 3 pontos a amostras metal/cerâmica, obten- do-se a resistência adesiva dos sistemas utilizados, de acordo com a norma ISO 9693-1999. Constituíram-se 6 grupos. Os grupos de ensaio foram fabricados a partir detitânio (Ti- grau 2) e duas cerâmicas: uma feldspática (IPS-Design) e outra indicada para a utilização com titânio (TRI-Triceram). Constituíram-se quatro grupos de controlo combinando ligas de CrCo e de AuPd com as duas cerâ- micas mencionadas anteriormente (TRI e IPS). As amos- tras foram analizadas posteriormente por Microscopia Electrónica de Varrimento (SEM/EDS) de forma a identificar o tipo de falha de união. Resultados: Dos seis grupos testados, unicamente o grupo Ti/IPS apresentou valores de resistência adesiva (18.09 ± 7.3 MPa) abaixo dos mínimos indicados na norma ISO (25 MPa). A caracterização do tipo de falha de ...
Laser surface alloying processes all the features of surface melting, plus additional capability ... more Laser surface alloying processes all the features of surface melting, plus additional capability of modifying the chemical composition by adding alloying elements which greatly enhance the wear and corrosion resistance of aluminium alloys. This paper is concerned with a study of the formation mechanism and structural changes of the alloyed layer during laser surface alloying aluminium with niobium...The material is
V. Livramento 1, a , MT Marques 1, b , JB Correia 1, c , A. Almeida 2, d , R. Vilar 2, e ... 1INE... more V. Livramento 1, a , MT Marques 1, b , JB Correia 1, c , A. Almeida 2, d , R. Vilar 2, e ... 1INETI-DMTP, Estrada do Paço do Lumiar, 22, 1649-038 LISBOA, Portugal; 2IST-Dep. Eng. de Materiais, Av. Rovisco Pais, 1049-001 Lisboa, Portugal ... Keywords: mechanical ...
422 Electrochemical Methods in Corrosion Research V minimise oxidation during LSM, argon gas was ... more 422 Electrochemical Methods in Corrosion Research V minimise oxidation during LSM, argon gas was blown over the molten pool. Table 1 - Nominal composition of 2024 aluminium alloy %Cu %Mg %Mn %A1 4.4 1.5 0.6 bal 7175-T7351 aluminium alloy plate with nominal ...
Uploads
Papers by Amelia Almeida