Salete Martins Alves

Micro and nanometric wear evaluation of metal discs used on determination of biodiesel fuel lubricity

The contact of diesel fuel with engine subsystems demands a good wear resistance. Lubricity is an important feature for integrity of injection system and the sulphur composites are primarily responsible for lubrication of the injector nozzle. Biodiesel is responsible for partially restoring the lubricity of diesel fuel that presents low levels of sulphur composites and, furthermore, it causes less pollution than diesel fuel. The lubricity is measured through the wear scar diameter following the ASTM D 975 standards. However, the friction and wear with light loads of micro/nanocomponents are highly dependent on surface interactions that can be evaluated by microscopy techniques. This study aimed to measure and to analyze the biodiesel lubricity and their blends (B5, B20) with diesel by observing the wear scars of discs using the scanning electronic microscopy (SEM), atomic force microscopy (AFM) and micro roughness techniques. The fuels performance was evaluated using HFRR tribometer. The tests conditions were based on standard ADTM D-6079-04. The coefficient of friction was measure during the test. After the test, the worn ball and disc were analyzed by SEM, AFM and profilometer. The results showed that the addition of biodiesel in diesel improve the tribological performance of fuel. Also, the just WSD value is not sufficient to evaluate the lubrication ability of a fuel. Analysis of the worn disc surfaces proved to be compatible with WSD number and also more sensitive to these kinds of fuels, showing mainly the form and intensity of the wear.

Study of oxide nanoparticles as additives for vegetable lubricants

Currently, vegetable oils have been studied as biolubricants in order to reach new environmental standards. Besides being non-renewable, mineral oils from petroleum bring consequences to the environment due to its low biodegradability. Thus, the aim of this work is to develop a biolubricant and to add oxide nanoparticles (ZnO and CuO) in order to improve abrasion resistance and friction. This product must be biodegradable and has better performance under boundary lubrication. The methodology consisted of the synthesis of biolubricants using vegetable oils (soybean and sunflower) by epoxidation reaction. The tribological performance was evaluated by HFRR (High Frequency Reciprocating Rig). The developed biolubricants showed good tribological properties besides being more adapted to the environment. Also, it was possible to verify that biolubricants without additives are slightly more tribologically effective than lubricants with additives.

Influence of EP additive on tool wear in drilling of compacted graphite iron

Compacted Graphite Iron (CGI) is a good option for the manufacturing of engine blocks, because of the possibilities to decrease the wall thickness and to operate at higher pressures. However, due to its greater tensile strength and hardness compared with grey cast iron, the pearlitic CGI structure makes its machining more difficult. Thus, the aim of this paper is to investigate the improvements in CGI drilling achieved through the use of cutting fluids with EP additives. Experimental investigation of the influence of an EP additive on the drilling process was carried out using a CNC machine with 7.64 kW of power and maximum rotation of 5000 rpm. The cutting parameters were a cutting speed of 110 m/min, feed velocity of 350 mm/min and hole-depth of 20 mm. Three cutting fluids were analyzed, with and without EP additives. The results showed that the EP additive influenced the CGI drilling performance due to a layer comprised of sulphur (EP additive) and metal. Adhesion was avoided and the friction and wear behavior was improved.

Effect of desulfurization of diesel and its blends with biodiesel on metallic contact

The current environmental scenario has required changes in fuel nature, in order to minimize the harmful effects caused by sulfur in diesel. However, reductions in sulfur content promote loss of its lubricity and consequently wear in the injection system of the diesel engine. This study aimed to investigate the influence of sulfur minimization on fuel lubricity and wear of metallic disks. The fuel tribological analysis was carried out in HFRR equipment in accordance with ASTM D 6079 - 04. The tested fuels were diesel oil with 50, 500 and 1800 ppm sulfur, and their blends of soybean and sunflower biodiesel (5, 20 and 100% in volume). The results showed an increase of disks wear with reduction of sulfur content when lubricated with pure diesel. This fact was decreased when biodiesel was added to all concentrations.

Correlation Between Fuel Lubricity and Vibration Signals Obtained in Ball-disc Analysis Using Fourier Transform

During the contact between metallic surfaces in mechanical systems, some dynamic characteristics present significant changes as the vibration signal patterns. The acquisition and characterization of these signals, by the use of Fourier Transform (FT), are non-intrusive tools in the evaluation of lubricity. This study aimed to evaluate dynamically the fuels lubricity (diesel S50, biodiesel and its blends) by the reciprocating sliding of a ball against a flat disc (AISI 52100 steel). After that, the vibration signals were evaluated by statistical test and FFT (Fast Fourier Transform) and STFT (Short-Time Fourier Transform) analyses and verified their associations with parameters supplied by ASTM D6079. The results present a correlation between lubricity, frequency spectrum and the parameters of profiles from the worn disc surface. In addition, the evolution of wear scars presented an influence of the biodiesel content in these fuels.

Biodiesel Compatibility with Elastomers and Steel

This chapter describes the compatibility of biodiesel with automotive components, such as metallic and polymeric materials. It consists of a survey of literature as well as research results obtained by the authors. Aspects as wear, corrosion, and degradation materials are discussed.

Synthesis of magnetic nanoparticles by microwave for aplication in lubricantion

The synthesis and characterization of magnetic nanoparticles have been widely studied due to their applications in several areas of knowledge. Obtaining nanomaterials as additives with specific properties for industrial lubricating oil has been getting many expectations that can minimize tribological problems, in addition the friction and wear handle failures in equipment and machinery. For iron oxide nanoparticles, the most important variations are caused by the observed phenomena that are intrinsic or become dominant in nano-scale. These phenomena include confinement due to the size, predominance interface phenomena and quantum phenomena. However, the study of these magnetic phenomena of nanoparticles is connected with type and morphology, directly influenced by the synthesis. Therefore the aim of this study is to synthesize the nanoparticles by microwave power 300W, in two different times and temperatures, 0.5 minutes and 2.0 minutes, 55° C and 95 ° C, respectively, obtaining them with different physical and chemical properties, also be characterized by X-Ray Diffraction and correlated with crystallite size, time, kinetic energy study nucleation and about how the magnetic nanoparticles can act as antiwear additives.

Leverage about synthesis and dispersion with cuo nanoparticle in oil lubricating

The challenge for nanotechnology application in automotive lubrication is the difficulty in dispersing the nanoparticles in lubricating oils. Some factors have a direct influence on the dispersion of particles, such as size and shape, which are controlled by the chosen synthesis method. In addition, the use of covers and dispersant agents aid the dispersion of nanoparticles in lubricating oils. In this work studied the effect of different amount of energy given during the synthesis of nanoparticles in microwaves, in order to observe its influence on the dispersion size and shape of nanoparticles. They were covered with oleic acid, as well disperse in toluene, improving nanoparticle dispersion. The dispersion in of nanoparticles in oil was observed by physical characteristic, spectroscopy in the visible ultraviolet (UV/VIS) and micrographs (MO). The results showed that the synthesis with higher amount of energy generated a smaller particle size and better dispersion in oil. However the nanoparticle shape is not influenced by energy amount. The use of Oleic acid and toluene improved the dispersion of the nanoparticles in the lubricant oil as observed in the results of UV/ VIS by biggest interparticle distance.