Joinville, Brazil
Joinville, Brazil

Time filter

Source Type

Rzatki F.D.,Federal University of Santa Catarina | Barboza D.V.D.,Federal University of Santa Catarina | Schroeder R.M.,Whirlpool Embraco | De O. Barra G.M.,Federal University of Santa Catarina | And 3 more authors.
Wear | Year: 2015

Polyether ether ketone (PEEK) composites and AISI 52100 steel are high-performance materials that are often selected for high stress tribological applications under solid and hydrodynamic lubrication. In this study, the viability of these materials as a pair for boundary-lubricated systems was evaluated. Tribo-tests to evaluate different characteristics were conducted: (i) the effect of metallic surface finish (1 μm polished, 9 μm polished, shot peened and ground); (ii) the effect of temperature (room temperature and 90°C); and (iii) the effect of long-term PEEK exposure to lubricant oil (i.e., chemical ageing). An AMTI tribometer equipped with a hermetic chamber and a heating system was used for reciprocating sliding tests with a 10 mm stroke, 2 Hz frequency and 2 h duration. The tests used a cylinder-on-disc configuration (polymer on metal), a tetrafluoroethane atmosphere and a 100 N normal force. The wear tracks were analysed using a light interferometer, SEM and optical microscope to assess the wear mechanisms, including transfer film formation. The surface skewness and transfer film establishment were the main factors affecting the friction coefficient. In contrast, the wear of the PEEK composites was mainly affected by the surface bearing index and chamber temperature. Moreover, transfer films were observed only on counterbodies that had a surface roughness (Sq) of at least 0.030 μm. Finally, accelerated ageing of PEEK composites was performed in an autoclave at 180°C and 3 bar pressure for 7 days in the presence of an ester-based lubricant oil and tetrafluoroethane atmosphere. DSC, DTG and FTIR techniques indicated that the filler/matrix interfaces of the PEEK composites were dissolved by the ester-based lubricant oil. Chemical ageing showed a significant effect on the friction steady state regime. Instead of a stable value, the friction coefficients of the aged composites increased slowly and continuously. © 2015ElsevierB.V.Allrightsreserved.


De Mello J.D.B.,Federal University of Uberlandia | Binder C.,Federal University of Santa Catarina | Binder R.,Whirlpool Embraco | Klein A.N.,Federal University of Santa Catarina
Society of Tribologists and Lubrication Engineers Annual Meeting and Exhibition 2010 | Year: 2010

Self-lubricating composite samples were produced using the powder injection molding process, plasma assisted debinding and sintering process, and in situ formation solid lubricant particles. The reference alloy presented a microstructure constituted of perlite and ferrite while the addition of SiC to the feedstock powder induced the formation of graphite nodules. Increasing the precursor content produced a reduction of the average friction coefficient. The nodules of graphite were mainly constituted of turbostratic two-dimensional which presents longer inter lamellae distances than the highly oriented three-dimensional graphite. The increase in distance may induce low interaction between these atomic planes, and was probably the origin of the low friction coefficient. This is an abstract of a paper presented at the STLE Annual Meeting and Exhibition 2010 (Las Vegas, NV 5/16-20/2010).


De Mello J.D.B.,Federal University of Uberlandia | Binder C.,Federal University of Santa Catarina | Binder R.,Whirlpool Embraco | Klein A.N.,Federal University of Santa Catarina
Wear | Year: 2011

The production of self lubrication composites containing second phase particles incorporated into the volume of the material appears to be a promising solution. A new processing route to obtaining a homogeneous dispersion of discrete solid lubricant particles in the volume of sintered steels produced by metal injection molding (MIM) was recently presented. This new route was achieved by in situ formation of graphite nodules due to the dissociation of precursor (SiC particles) mixed with the metallic matrix powders during the feedstock preparation. Nodules of graphite (size ≤20. μm) presenting a nanostructured stacking of graphite foils a few nanometers thick were obtained. The thermal debinding, as well as the sintering, was performed in a single thermal cycle using a Plasma Assisted Debinding and Sintering (PADS) process. In this work, we present and discuss the effect of precursor content and sintering temperature on the scuffing resistance of plasma assisted debinded and sintered self lubricating steel produced by metal injection mould technique. Three different temperatures (1100, 1150 and 1200. °C) and six different SiC contents (0-5%) were analyzed. Increasing the precursor content and, as a consequence, the number of graphite nodules, produced a clear increase in scuffing resistance for all analyzed sintering temperatures. Friction coefficient was little affected by the sintering temperature. However, the scuffing resistance was greatly increased (5×) for the lower sintering temperature (1100. °C). © 2011 Elsevier B.V.


Kalluf F.,Whirlpool Embraco | Espindola A.,Whirlpool Embraco | Tutelea L.,Polytechnic University of Timişoara | Boldea I.,Polytechnic University of Timişoara
2012 IEEE Energy Conversion Congress and Exposition, ECCE 2012 | Year: 2012

Compressor electric motor drives play a key role in energy consumption of residential refrigerators. Electrical efficiency, robustness to starting and overloads and speed variation range define the performance of compressor electric motor drives. Between the lowest cost fixed speed split phase capacitor grid-connected induction motor, with lower efficiency, and the higher-efficiency grid connected cage PM rotor split phase capacitor motor and the inverter fed variable PM synchronous motor of highest initial costs, we introduce in this paper a 2 speed grid-connected motor drive. The proposed topology uses a separate split phase winding, cage-PM-four-pole rotor synchronous motor (PMSM) for low speed (4 pole) and a single phase (main) winding for 2 pole operation. The target is 85% efficiency at 50W output for 4 poles (low speed) PMSM operation with good starting and at least 60% efficiency in 2 pole (high speed) induction motor operation at 100W, with smooth transients from low to high speed under full torque load. Circuit models for steady state and for transients with dedicated Matlab codes have been developed, with key FEM validation, to substantiate full scale experiments as the main contributions of the paper for a ready to use industrial solution. © 2012 IEEE.


Klein A.N.,Federal University of Santa Catarina | Binder C.,Federal University of Santa Catarina | Schroeder R.,Federal University of Santa Catarina | De Mello J.D.B.,Federal University of Uberlandia | Binder R.,Whirlpool Embraco
Advances in Powder Metallurgy and Particulate Materials - 2011, Proceedings of the 2011 International Conference on Powder Metallurgy and Particulate Materials, PowderMet 2011 | Year: 2011

A new processing route to obtain a homogeneous dispersion of discrete particles of solid lubricant in the volume of sintered steels produced by metal injection molding (MIM) was recently presented. This was achieved by in situ formation of graphite nodules due to the dissociation of precursor (SiC particles) mixed with the metallic matrix powders during the feedstock preparation. Nodules of graphite (size ≤ 20μm) presenting a nanostructured stacking of graphite foils a few nanometers thick were obtained. The thermal debinding, as well as the sintering, was performed in a single thermal cycle using a Plasma Assisted Debinding and Sintering (PADS) process. In this work, we present and discuss the effect of metallic matrices on the tribological behavior of plasma assisted debinded and sintered self lubricating steel. Three different matrix compositions (Fe+0.6C; Fe+0.6C+4.0%Ni; Fe+0,6C+4.0%Ni+1.0%Mo) were analyzed. Friction coefficient and wear rate (sample and counter-body) were greatly affected by the composition of the matrices.


De Mello J.D.B.,Federal University of Uberlandia | Binder C.,Federal University of Santa Catarina | Binder R.,Whirlpool Embraco | Klein A.N.,Federal University of Santa Catarina
Tribology - Materials, Surfaces and Interfaces | Year: 2010

In the present investigation, the effect of plasma nitriding on the microabrasion behaviour of sintered unalloyed iron is investigated. Plasma nitriding was carried using two different sets of operative parameters in order to produce microstructures composed of different dominants iron nitrides, e.g. Fe 4N (γ′) and Fe 2-3N (ε), phases. Microabrasive wear tests were carried out in a 'free ball' microabrasion tester using SiC slurries. The tribological parameters were kept constant during the tests. The microstructures constituted of ε-(Fe 2-3N) phase presented a superior abrasion resistance. © 2010 W. S. Maney & Son Ltd.


Hammes G.,Federal University of Santa Catarina | Binder C.,Federal University of Santa Catarina | Klein A.N.,Federal University of Santa Catarina | De Mello J.D.B.,Federal University of Uberlandia | Schroeder R.,Whirlpool Embraco
Advances in Powder Metallurgy and Particulate Materials - 2014, Proceedings of the 2014 World Congress on Powder Metallurgy and Particulate Materials, PM 2014 | Year: 2014

This work presents the effect of double press and double sinter (DPDS) technique on the mechanical and tribological properties of self-lubricating composites. The matrix composition was based on a Fe-Mo-CSi alloy, and the solid lubricants, added during mixing step, were hexagonal boron nitride (hBN) and graphite. The samples were produced by single and double press techniques, for comparison, and were evaluated in terms of hardness, tensile strength and sliding wear. The compaction technique had almost no influence on friction coefficient and wear rate of both specimens and counter-bodies, whereas DPDS significantly increased scuffing resistance. This effect is directly related to a reduction in porosity, which in turn causes an improvement in the mechanical strength of the composites.

Loading Whirlpool Embraco collaborators
Loading Whirlpool Embraco collaborators