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The purpose of this paper is to investigate the influence of binder effect on tribological behavior of brake friction composite materials: a case study of phenolic resin modified by N-Methylaniline.

Four different friction materials have been fabricated by varying modified phenolic resin content. The samples were prepared by the conventional powder metallurgy methods following ball milling, mixing, pre-forming, hot pressing and post-curing processes. Thermogravimetric analysis was used to determination of the degradation mechanism of organic components and study of thermal stability of the samples. A friction test was carried out in dry conditions using a vertical tribometer. Analysis of worn surfaces was performed using a scanning electron microscope.

The experimental results revealed that the sample containing 25 Wt.% phenolic resin has good mechanical and thermal properties with stable friction characteristics.

This paper presents the effect of N-methylaniline modified phenolic resin on friction composites to improve tribological performance by its thermal properties.

THE BENEFIT of lubricants and of additives an “lubricant modifiers” has been known for centuries. For example, animal fat was used to reduce friction and thus squeaking, of Roman chariot wheels sulphur was employed to aid the machining of iron during the Industrial Revolution, The type of additives which will be discussed in this paper are, however, of more recent origin and are complex chemical compounds which are added in controlled quantities to lubricating fluids to enhance or modify their specific natural properties.

The research aims to investigate the impact of thermo-mechanical aging on SBR under cyclic-loading. By conducting experimental analyses and developing a 3D finite element analysis (FEA) model, it seeks to understand chemical and physical changes during aging processes. This research provides insights into nonlinear mechanical behavior, stress softening and microstructural alterations in SBR compounds, improving material performance and guiding future strategies.

This study combines experimental analyses, including cyclic tensile loading, attenuated total reflection (ATR), spectroscopy and energy-dispersive X-ray spectroscopy (EDS) line scans, to investigate the effects of thermo-mechanical aging (TMA) on carbon-black (CB) reinforced styrene-butadiene rubber (SBR). It employs a 3D FEA model using the Abaqus/Implicit code to comprehend the nonlinear behavior and stress softening response, offering a holistic understanding of aging processes and mechanical behavior under cyclic-loading.

This study reveals significant insights into SBR behavior during thermo-mechanical aging. Findings include surface roughness variations, chemical alterations and microstructural changes. Notably, a partial recovery of stiffness was observed as a function of CB volume fraction. The developed 3D FEA model accurately depicts nonlinear behavior, stress softening and strain fields around CB particles in unstressed states, predicting hysteresis and energy dissipation in aged SBRs.

This research offers novel insights by comprehensively investigating the impact of thermo-mechanical aging on CB-reinforced-SBR. The fusion of experimental techniques with FEA simulations reveals time-dependent mechanical behavior and microstructural changes in SBR materials. The model serves as a valuable tool for predicting material responses under various conditions, advancing the design and engineering of SBR-based products across industries.

The objective of this study was to evaluate the antioxidant effect of oregano and thyme extracts isolatedly and combinedly applied in soybean oil.

Soybean oil containing 3,000 mg/kg of oregano and thyme oleoresins and the mixture of both, as well as soybean oil containing TBHQ (50 mg/kg) and soybean oil free of antioxidants, were subjected to accelerated oven test (60°C/10 days). Samples were collected every two days and analyzed as to their peroxide and conjugated diene values.

The mixture of oleoresins and consequent increase of concentration were as effective as the antioxidant TBHQ.

These studies may prove to be beneficial to the exploitation of natural antioxidant sources for the preservation and/or extension of raw and processed food shelf life. Therefore, they could also be applied in the area of pharmaceuticals for the protection of human life.

This study offers information on the use of natural antioxidants as an alternative to the use of synthetic antioxidants, which might be considered toxic.

This paper aims to investigate the structural, tribological and electrochemical properties of Ag₂O, ZnO, NiO coatings and Ag₂O/ZnO/NiO nanocomposite films deposited on commercially pure titanium.

Ceramic thin films (Ag₂O, ZnO, NiO coatings and Ag₂O/ZnO/NiO nanocomposite film) were deposited on commercially pure titanium (CP-Ti) substrate. Surface characterization of the uncoated and coated samples was made by structural surveys (scanning electron microscopic examinations and X-ray diffraction analyses), hardness measurements, tribological and corrosion experiments.

Results were indicated that sol-gel coatings improved the wear and corrosion resistance of CP-Ti, and the best results were seen at the nanocomposite coating. It may be attributed to its small grain size, high surface hardness and high film thickness.

This study can be a practical reference and offers insight into the influence of nanocomposite ceramic films on the increase of hardness, tribological and corrosion performance. Also, the paper displayed a promising approach to produce Ag₂O/ZnO/NiO nanocomposite coating on commercially pure titanium implants for biomedical applications.

This paper aims to investigate the thermal oxidation characteristics of the unsaturated bonds (C=C) of trimethylolpropane trioleate (TMPTO) and to reveal the high temperature oxidation decay mechanism of unsaturated esters and the nature of the anti-oxidation properties of the additives.

Using a DXR laser microscopic Raman spectrometer and Linkam FTIR600 temperature control platform, the isothermal oxidation experiments of TMPTO with or without 1.0 wt. % of different antioxidants were performed.

The results indicated that the Raman peaks of =C-H, C=C and -CH₂- weaken gradually with prolonged oxidation time, and the corresponding Raman intensities drop rapidly at higher temperatures. The aromatic amine antioxidant can decrease the attenuation of peak intensity, as it significantly reduces the rate constant of C=C thermal oxidation. The hindered phenolic antioxidant has a protective effect during the early stages of oxidation (induction period), but it may accelerate the oxidation of C=C afterwards.

Research on the structure changes of synthetic esters during oxidation by Raman spectroscopy will be of great importance in promoting the use of Raman spectroscopy to analyze the oxidation of lubricants.

This paper aims to analyse the surface evolution of pure recycled titanium subjected to isothermal and cyclic oxidation conditions using dry air as oxidant gas. It is important to mention that the cyclic oxidation behaviour of pure titanium is a process that has been barely studied.

An isothermal and cyclic oxidation reactor was built for these purposes. This installation allows the oxidation of material under the action of any atmosphere and for temperatures up to 1,200°C. For this study, the oxidation behaviour of the material was studied at 850°C and 950°C.

Oxide growth under isothermal oxidation conditions in air follows a parabolic behaviour with an activation energy of 118 kJ/mol, and the oxide phase formed on the surface of the metal was rutile. The cyclic oxidation of the material indicates that oxide is spalled from the surface following linear behaviours; this phenomenon is controlled by the thermal stresses experienced by the samples during heating and cooling cycles.

The material is obtained from the production of electrolytic copper, and during its reprocessing practices at high temperature, it was thought that it could experience some abnormal oxidation. In addition, given that pure titanium is currently used for biomedical application, some surface degree can be given by means of oxidation and subsequent spallation process situation that is found during the cyclic oxidation experiments, which could be a low-cost method to engineer a surface for these purposes.

This paper aims to discuss that a WC/Co-Cr alloy coating was applied to the surface of H13 steel by laser cladding.

The oxidation behavior of the WC/Co-Cr alloy coating at 600°C was investigated by comparing it with the performance of the steel substrate to better understand the thermal stability of H13 steel.

The results showed that the WC/Co-Cr alloy coating exhibited better high-temperature oxidation resistance and thermal stability than did uncoated H13 steel. The coated H13 steel had a lower mass gain rate and higher microhardness than did the substrate after different oxidation times.

The WC/Co-Cr alloy coating was composed of e-Co, CW3, Co6W6C, Cr23C6 and Cr7C3; this mixture offered good thermal stability and better high-temperature oxidation resistance.

In this paper, a formula for life prediction of SMT solder joints under thermal cycling has been established on a damage model. The major failure mechanisms such as fatigue, creep and atmospheric oxidation have been considered in the formula. The experimental verification shows that the life formula established in this paper coincides with the experimental results.