2013

Valerini D.a, Signore M.A.a, Tapfer L.a, Piscopiello E.a, Galietti U.b, Rizzo A.a
(2013) Thin Solid Films, 538, pp. 42-47.
aENEA, Italian National Agency for New Technologies, Energy and Sustainable Economic Development, Technical Unit for Brindisi Material Technologies, S.S. 7 Appia, Km. 706, 72100 Brindisi, Italy;
bPolitecnico di Bari, Dipartimento di Ingegneria Meccanica e Gestionale, Viale Japigia 182, 70126 Bari, Italy
Abstract
The improvement of the adhesion of a coating film to the coated material and of its wear resistance is a fundamental aspect for protective hard coatings. As a consequence, the optimization of the deposition techniques is required to properly tune the film properties. Among the numerous materials for hard coatings, zirconium nitride (ZrN) is extensively studied for use in tribological applications, thanks to its high hardness, strong wear resistance, chemical stability and high corrosion resistance. In this work ZrN films were RF-sputtered on silicon and tungsten carbide substrates, with different assistance bias voltages applied to the substrate during the film deposition. Their adhesion and wear resistance properties were evaluated and correlated to the structural and compositional properties, showing the best responses (higher critical load and scratch hardness, and lower wear rate) when using a low negative bias voltage (- 5 V). © 2012 Elsevier B.V. All rights reserved.
Author Keywords
Adhesion; Wear; Zirconium nitride
Document Type: Conference Paper
Source: Scopus

 

Laera A.M., Resta V., Piscopiello E., Miceli V., Schioppa M., Scalone A.G., Di Benedetto F., Tapfer L.
(2013) Nanoscale Research Letters, 8 (1), pp. 1-8.
ENEA, Technical Unit for Material Technologies, Brindisi Research Centre, Strada Statale 7, Appia km 706, Brindisi 72100, Italy
Abstract
A straight synthetic route to fabricate hybrid nanocomposite films of well-dispersed CdS nanocrystals (NCs) in poly[2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene vinylene] (MEH-PPV) is reported. A soluble cadmium complex [Cd(SBz)2]2·MI, obtained by incorporating a Lewis base (1-methylimidazole, MI) on the cadmium bis(benzyl)thiol, is used as starting reagent in an in situ thermolytic process. CdS NCs with spherical shape nucleate and grow well below 200°C in a relatively short time (30 min). Photoluminescence spectroscopy measurements performed on CdS/MEH-PPV nanocomposites show that CdS photoluminescence peaks are totally quenched inside MEH-PPV, if compared to CdS/PMMA nanocomposites, as expected due to overlapping of the polymer absorption and CdS emission spectra. The CdS NCs are well-dispersed in size and homogeneously distributed within MEH-PPV matrix as proved by transmission electron microscopy. Nanocomposites with different precursor/polymer weight ratios were prepared in the range from 1:4 to 4:1. Highly dense materials, without NCs clustering, were obtained for a weight/weight ratio of 2:3 between precursor and polymer, making these nanocomposites particularly suitable for optoelectronic and solar energy conversion applications. © 2013 Laera et al.; licensee Springer.
Author Keywords
Chemical synthesis; Hybrid nanocomposites; Nanocrystals
Document Type: Article
Source: Scopus

 

Rizzo A.a, Mirenghi L.a, Massaro M.a, Galietti U.b, Capodieci L.a, Terzi R.a, Tapfer L.a, Valerini D.a
(2013) Surface and Coatings Technology, 235, pp. 475-483. Cited 2 times.
aENEA - Italian National Agency for New Technologies, Energy and the Sustainable Economic Development, Technical Unit for Materials Technologies, Brindisi Research Center, S.S. 7 Appia km. 706, 72100 Brindisi, Italy;
bPolitecnico di Bari, DIMEG - Dipartimento di Ingegneria Meccanica e Gestionale, Viale Japigia 182, I-70126 Bari, Italy
Abstract
TiAlN/AlN multilayers are attracting great interest for the possibility to modulate their mechanical and tribological properties through the variation of multilayer design. In this work TiAlN single layer, TiAlN/AlN intermixed-multilayer and nano-multilayer were prepared using a reactive magnetron sputtering system starting from targets of TiAl and Al. The aim is to analyze how the multilayer design affects the thermal and tribological properties of the coatings. The microstructure of as-deposited and annealed films has been studied using X-ray diffraction. The chemical composition has been deduced by XPS analyses. Thermal behavior was assessed by means of differential thermal analysis (DTA) and thermogravimetric analysis (TGA), while mechanical properties have been investigated by wear tests. © 2013 The Authors.
Author Keywords
Multilayers; Reactive magnetron sputtering deposition; TiAlN
Document Type: Article
Source: Scopus

 

Di Girolamo G.a, Marra F.b, Pilloni L.c, Pulci G.b, Tirillò J.b, Valente T.b
(2013) International Journal of Applied Ceramic Technology, 10 (1), pp. 60-71. Cited 4 times.
aENEA, UTTMATB, Brindisi Research Center, 72100 Brindisi, Italy;
bDepartment of Chemical and Materials Engineering, University of Rome la Sapienza, UdR INSTM Roma la Sapienza, 00184 Rome, Italy;
cENEA, UTTMAT, Casaccia Research Center, 00123 Rome, Italy
Abstract
Atmospheric plasma spraying of WC-Co particles with standard gas mixtures (Ar-H2) typically results in largely decarburized coatings with relatively low wear resistance. To fabricate cermet coatings with enhanced tribological properties, nanostructured WC-Co coatings were plasma sprayed using two different process gas mixtures. Phase composition and microstructure were investigated by X-ray diffraction and scanning electron microscopy, respectively. Microhardness increased by increasing the amount of retained WC grains in coating microstructure. Friction and wear properties, measured under dry sliding conditions, strongly depended on the degree of decarburization. They were comparable to those of conventional coatings produced using identical conditions. © 2012 The American Ceramic Society.
Document Type: Article
Source: Scopus

 

Abazović N.D.a, Čomor M.I.a, Mitrić M.N.a, Piscopiello E.b, Radetić T.c, Janković I.A.a, Nedeljković J.M.a
(2013) Journal of Nanoparticle Research, 15 (1), art. no. 1292
aVinča Institute of Nuclear Sciences, University of Belgrade, P.O. Box 522, 11001 Belgrade, Serbia;
bDepartment of Advanced Physics Technology and New Materials (FIM), ENEA, Strada Statale 'Appia', 72100 Brindisi, Italy;
cDepartment of Metallurgical Engineering, Faculty of Technology and Metallurgy, University of Belgrade, Karnegijeva 4, 11000 Belgrade, Serbia
Abstract
[No abstract available]
Document Type: Erratum
Source: Scopus

 

De Riccardis M.F.a, Martina V.b, Carbone D.a
(2013) Journal of Physical Chemistry B, 117 (6), pp. 1592-1599. Cited 1 time.
aENEA, Unità Tecnica Tecnologie Dei Materiali Brindisi (UTTMATB), C.R. Brindisi, SS. 7 APPIA KM 706, 72100 Brindisi, Italy;
bCETMA, Brindisi, SS. 7 APPIA KM 706, 72100 Brindisi, Italy
Abstract
Recently a great interest has been expressed in electrophoretic deposition (EPD) of polymers, both as particles and as chains. It is generally accepted that also for polymer particles, the Derjaguin-Landau-Verwey-Overbeek (DLVO) theory is valid, therefore, in principle, polymer suspensions suitable for EPD could be easily obtained by dispersing polymer particles in an aqueous or nonaqueous medium. Nevertheless, this work demonstrated that in order to obtain good quality deposits based on poly(ether ether ketone) (PEEK) and poly(tetrafluoroethylene) (PTFE), some additives have to be used. In the case of PEEK, a dispersant providing citrate anions was successfully used, whereas for PTFE a steric suspension stabilization was reached by adding polyvinylpyrrolidone (PVP). In such a way, codeposition of PEEK and PTFE was achieved. The efficiency of the EPD process was demonstrated by means of differential scanning calorimetry (DSC) measurements. A thermal program consisting of heat/cool/heat cycles at a low rate was used in order to evaluate the crystalline amount of each polymer in the deposits. In order to explain the obtained results, it needed to also consider the dimension and structural characteristic of the polymer particles. © 2012 American Chemical Society.
Document Type: Article
Source: Scopus

 

Di Benedetto F.af, Fasano V.bc, Persano L.ab, Maruccio C.e, Mele E.b, Potente G.a, Weitz D.A.dg, De Lorenzis L.e, Pisignano D.abc
(2013) Soft Matter, 9 (7), pp. 2206-2211. Cited 3 times.
aNational Nanotechnology Laboratory of Istituto Nanoscienze-CNR, Università Del Salento, via Arnesano, I-73100 Lecce, Italy;
bCenter for Biomolecular Nanotechnologies, Istituto Italiano di Tecnologia (I.I.T.), via Barsanti 1, I-73010 Arnesano-LE, Italy;
cDipartimento di Matematica e Fisica ennio de Giorgi, Università Del, via Arnesano, I-73100 Lecce, Italy;
dDepartment of Physics, School of Engineering and Applied Sciences, Harvard University, Cambridge, MA 02138, United States;
eDipartimento di Ingegneria dell'Innovazione, Università Del Salento, via Arnesano, I-73100 Lecce, Italy;
fENEA, Technical Unit OfMaterial Technologies Brindisi, Strada Statale 7 Appia km. 706, 72100 Brindisi, Italy;
gNanophysics, Istituto Italiano di Tecnologia (I.I.T.), via Morego 30, 16163 Genova, Italy
Abstract
Elastomeric polymeric microspheres are employed as a direct-writing tool for the continuous delivery of molecular materials. The mechanical properties enabling patterning are investigated and modelled. The proposed approach provides a low cost and versatile lithographic method for transferring features with real-time dynamic control. This journal is © 2013 The Royal Society of Chemistry.
Document Type: Article
Source: Scopus

 

De Giorgi M.G.a, Campilongo S.a, Ficarella A.a, Coltelli M.b, Pfister V.c, Sepe F.d
(2013) Proceedings of the ASME Turbo Expo, vol. 2
aUniversity of Salento, Dep. Engineering for Innovation, Lecce, Italy;
bIstituto Nazionale di Geofisica e Vulcanologia, Osservatorio Etneo - Sezione di Catania, Italy;
cENEA, Technical Unit for Material Technologies, Brindisi, Italy;
dENAC, Italian Civil Aviation Authority, Roma, Italy
Abstract
This study is focused on volcanic ash ingestion in aircraft engines, that can lead to slow but constant deterioration in engine performance and engine failure because of the mechanical damages to the wall surface. In particular the particles that impact on blades surfaces cause erosion damage and permanent losses in engine performance. Aircraft engine fans could be severely damaged by the ash flow. In order to clarify the erosion phenomenon the fan has been simulated through the general-purpose CFD code and the numerical simulations were performed using the Reynolds-Averaged Navier-Stokes (RANS). After validating the numerical modeling of the flow without erosion by comparisons with experimental data in literature, a surface injection of a discrete phase has been introduced in order to evaluate particle ingestion of volcanic ash. This phenomenon is a typical gasparticle two-phase turbulent flow and a multi-physics problem where the flow field, particle trajectory and wall deformation interact with among others. A wide experimental investigation has been carried out on an ash sample from Etna volcano. In particular a sieve analysis to obtain particles dimensional distribution and an analysis of SEM images to calculate particles shape factor. These data were used to modeling the particle injection in the CFD model. The numerical investigation was aimed to clarify the effects of particle erosion and to evaluate the change of the flow field in the case of eroded blades. By erosion rate patterns, the eroded mass was estimated and it was used to model the eroded geometry, by a user routine implemented in the dynamic mesh module of the code. So the performances of the damaged fan were estimated and compared with the baseline geometry without erosion. Copyright © 2013 by ASME.
Document Type: Conference Paper
Source: Scopus