32 documents found, page 1 of 4
Elaboration and experimental characterizations of copper-filled polyamide micro...
Akrout, Mabrouka; Difallah, Basma Ben; Kharrat, Mohamed; Dammak, Maher; Pereira, António B.; Oliveira, Filipe J.; Duarte, IsabelPolyamide 66 (PA66) has been used for dynamic bearing applications due to its good wear and abrasion resistance, hardness, and rigidity. PA66/copper micro-composites were studied with respect to micro-mechanical, tribological, and structural properties. A mixing step followed by injection molding was used to develop the different composites: PA66+5 wt.% Cu, PA66+10 wt.% Cu, and PA66+15 wt.% Cu. The morphologica...
Nano-TiC-reinforced 18Ni300 steel manufactured by Powder Bed Fusion-Laser Beam ...
Ferreira, Daniel F. S.; Miranda, G.; Oliveira, Filipe J.; Oliveira, José M.In injection moulding, surfaces can be exposed to harsh working conditions, especially when polymers reinforced with abrasive glass fibres are used. Low carbon martensitic steels, such as maraging steels, are an excellent choice for demanding and complex mould inserts produced by Powder Bed Fusion-Laser Beam (PBF-LB). However, their wear resistance is lower than that of tool steels such as AISI D2 or H13, whose...
Electrochemical advanced oxidation processes using diamond technology: a critic...
Brosler, Priscilla; Girão, Ana V.; Silva, Rui F.; Tedim, João; Oliveira, Filipe J.Re-evaluation of conventional wastewater treatment processes is of paramount importance to improve the overall quality of our aquatic environment. Electrochemical Advanced Oxidation Processes (EAOPs) are the most promising alternative methods with application in wastewater treatment facilities since in situ electrogenerated oxidant agents degrade and mineralize a wide range of water pollutants. Boron-doped diam...
On the Structural, Thermal, Micromechanical and Tribological Characterizations ...
Akrout, Mabrouka; Ben Difallah, Basma; Kharrat, Mohamed; Dammak, Maher; Pereira, António; Oliveira, Filipe J.; Duarte, IsabelThe purpose of this work was to investigate the structural, thermal, micromechanical and tribological properties of novel polymer/metal composite materials for bearing applications. Copper (Cu)-filled Acrylonitrile Butadiene Styrene (ABS) composites were mixed in a laboratory scale by an internal mixer with two blade impellers, and then injection-molded. Neat ABS, ABS+5wt% Cu, ABS+10wt% Cu, and ABS+15wt% Cu wer...
Electroconductive silicon nitride-titanium nitride ceramic substrates for CVD d...
Brosler, Priscilla; Silva, Rui F.; Tedim, João; Oliveira, Filipe J.The present investigation was carried out to develop dense ceramics of silicon nitride-titanium nitride (Si3N4–TiN) with low electrical resistivity and excellent mechanical properties. The objective was to employ these ceramics as substrates of conductive diamond electrodes produced by chemical vapor deposition (CVD) for electrochemical applications. TiN powder was added to a Si3N4 matrix powder composition at ...
Diamond coated fiber optic interferometric sensors: fabrication and application
Kyatam, Shusmitha; Oliveira, Ricardo; Rocha, Ana M.; Mukherjee, Debarati; Neto, Miguel A.; Oliveira, Filipe J.; Khan, Muhammad A.; Correia, Maria R. P.Diamond films were deposited by chemical vapor deposition (CVD) on the tip of Fabry-Perot (FPI) and multi-mode (MMI) optical fiber interferometers. Diamond provides a robust interface capable of forming covalent bonds between atoms on its surface and receptor molecules, required for biosensing applications. The films were characterized by optical and scanning electron microscopy (SEM), optical profilometry and ...
In-house vs. commercial boron-doped diamond electrodes for electrochemical degr...
Brosler, Priscilla; Girão, Ana Violeta; Silva, Rui F.; Tedim, João; Oliveira, Filipe J.Boron-doped diamond (BDD) electrodes are eco-friendly and widely used in efficient water remediation through electrochemical advanced oxidation processes (EAOPs). These anodes can completely mineralize a wide range of pollutants, only requiring electrical energy. Over the last 2 decades, numerous commercially available BDD electrodes have emerged, but little is known about their electrooxidation performance, pa...
Advances in rf glow discharge optical emission spectrometry characterization of...
Sharma, Dhananjay K.; Girão, Ana V.; Chapon, Patrick; Neto, Miguel A.; Oliveira, Filipe J.; Silva, Rui F.Accurate determination of the effective doping range within diamond thin films is important for fine-tuning of electrical conductivity. Nevertheless, it is not easily attainable by the commonly adopted techniques. In this work, pulsed RF glow discharge optical emission spectrometry (GD-OES) combined with ultrafast sputtering (UFS) is applied for the first time to acquire elemental depth profiles of intrinsic di...
Dry sliding wear and mechanical behaviour of selective laser melting processed ...
Ferreira, Daniel F.S.; Vieira, João S.; Rodrigues, S. R.; Miranda, G.; Oliveira, Filipe J.; Oliveira, José M.In today’s manufacturing, selective laser melting (SLM) enables the production of 3D metal parts with innovative designs. However, this technique is still limited to certain materials due to residual stresses and cracking. The ultra-low carbon maraging steel 18Ni300 is a proven steel for SLM processing, while H13 steel still presents some challenges due to cracking and low wettability. These two steels are curr...
Conventionally and SLM-manufactured 18Ni300 steel: mechanical and tribological ...
Ferreira, Daniel F. S.; Miranda, G.; Oliveira, Filipe J.; Oliveira, José M.The high mechanical performance of 18Ni300 maraging steel, achieved during ageing treatment by precipitation of fine intermetallic precipitates within a martensitic matrix, makes this material a good choice for demanding applications such as injection moulds for the automotive industry. Its ease of manufacturing by selective laser melting (SLM) allows parts with a higher degree of complexity as well as the poss...