Saikrishnan G., Jayakumari L.S., Vijay R. and Lenin Singaravelu D.
The purpose of this study is to investigate the influence of commercially available iron–aluminum alloy compared to copper, iron and aluminum powders on the tribological…
Abstract
Purpose
The purpose of this study is to investigate the influence of commercially available iron–aluminum alloy compared to copper, iron and aluminum powders on the tribological performances of friction composites. The main objective is to replace copper from the friction composite formulations.
Design/methodology/approach
In this study, friction composites were fabricated as of standard brake pads using commercially available iron–aluminum alloy and compared to copper powder, iron powder and aluminum powder-based without varying the other ingredients. The brake pads were developed as per the industrial procedure. The physical, mechanical and thermal properties of the developed brake pads were analyzed as per industrial standards. Tribological properties were analyzed using the chase test. Initial speed and deceleration tests in a real-time braking scenario were performed using a full-scale inertia brake dynamometer. Worn surface analysis was done using a scanning electron microscope.
Findings
The results indicate that iron–aluminum alloy (mechanomade)-based friction composites possess good physical, chemical, thermal and mechanical properties with stable fade and recovery characteristics due to its composition and flake morphology. During initial speed and deceleration braking conditions, iron–aluminum alloy also showed good tribological behavior.
Originality/value
This paper explains the influence of commercially available iron–aluminum alloy in friction composites in enhancing tribological performance by its composition and flake morphology, which could potentially replace copper in friction composites by solving subsequent problems.
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Saikrishnan G., Jayakumari L.S. and Vijay R.
The purpose of this paper is to deal with the tribological study on the brake pads developed using various purity-based graphitized graphite.
Abstract
Purpose
The purpose of this paper is to deal with the tribological study on the brake pads developed using various purity-based graphitized graphite.
Design/methodology/approach
This paper deals with developing copper-free brake pads by using graphite as a key lubricant produced using a graphitization process with purity percentages (85, 90 and 95%). The brake pads were developed using traditional manufacturing processes and evaluated for their physical, chemical, thermal and mechanical properties as per industrial standards. Fade and recovery characteristics were analyzed using a full-scale inertia brake dynamometer as per JASO-C-406. The scanning electron microscope was used to analyze the worn surfaces of the brake pads.
Findings
The testing findings reveal that the brake pads with 95% graphitized graphite showed better shear strength with good adhesion levels and lesser density, hardness, acetone extract value, loss on ignition and higher porosity. Effectiveness studies of brake pads with graphite (95% graphitized) showed better results at higher pressure speed conditions than others because of better plateau formation and adequate lubrication.
Originality/value
This paper discusses graphitized graphite of different purity influences brake pad's tribological performance by modifying tribo-films and reducing friction undulations.
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J. Rajakumar, P. Saikrishnan and A. Chamkha
The purpose of this paper is to consider axisymmetric mixed convection flow of water over a sphere with variable viscosity and Prandtl number and an applied magnetic field.
Abstract
Purpose
The purpose of this paper is to consider axisymmetric mixed convection flow of water over a sphere with variable viscosity and Prandtl number and an applied magnetic field.
Design/methodology/approach
The non-similar solutions have been obtained from the origin of the streamwise co-ordinate to the point of zero skin friction using quasilinearization technique with an implicit finite-difference scheme.
Findings
The effect of M is not notable on the temperature and heat transfer coefficient when λ is large. The skin friction coefficient and velocity profile are enhance with the increase of MHD parameter M when λ is small. Viscous dissipation has no significant on the skin friction coefficient under MHD effect. For M=1, the movement of the slot or slot suction or slot injection do not cause any effect on flow separation. The slot suction and the movement of the slot in downstream direction delay the point of zero skin friction for M=0.
Originality/value
The present results are original and new for water boundary-layer flow over sphere in mixed convection flow with MHD effect and non-uniform mass transfer. So this study would be useful in analysing the skin friction and heat transfer coefficient on sphere of mixed convection flow of water boundary layer with MHD effect.
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This study aims to determine the braking performance of limestone as a filler in brake friction materials.
Abstract
Purpose
This study aims to determine the braking performance of limestone as a filler in brake friction materials.
Design/methodology/approach
Samples containing limestone material (30-35-40%), which can be an alternative to brake friction material filler, were produced. The samples were weighed on precision scales, mixed homogeneously and produced using the hot molding method. The physical and tribological properties of the produced samples were determined, and their microscopic analyzes were made with scanning electron microscopy.
Findings
As the amount of limestone increased, the density of the samples decreased. The friction coefficient and wear rates were close to each other and within the optimum limits for all samples. Limestone materials can be used instead of barite materials studied in the literature on brake linings. Microcracks were observed only in samples containing 30% and 35% limestone in microscopic images.
Originality/value
In this study, the wear rate, coefficient of friction and microstructures on the friction surfaces of brake friction materials containing limestone were investigated. The usability of limestone as a filler in brake friction materials provides valuable information to researchers and industrial organizations in the brake friction material field.
Sundarrajan D., Pitchipoo Pandian and Manoharan Sembian
This paper aims to deal with the synergistic effect of steel slag-molybdenum disulfide particles on fade-recovery performances of non-asbestos organic friction material.
Abstract
Purpose
This paper aims to deal with the synergistic effect of steel slag-molybdenum disulfide particles on fade-recovery performances of non-asbestos organic friction material.
Design/methodology/approach
The brake friction materials were developed by using steel slag and molybdenum disulfide particles as individual and combination in the formulation. The brake friction materials were developed in the form of standard brake pads as per the industrial practice. The physical, mechanical and thermal properties of the developed brake pads were tested as per the industrial standards. The tribological properties were analyzed using the Chase test as per IS2742-Part-4. Worn surface analysis was done using a scanning electron microscope.
Findings
The experimental results indicate that the brake pads filled with a combination of steel slag and molybdenum disulfide showed stable friction and less wear rate due to the synergetic nature of abrasive and lubricant.
Originality/value
This paper explains the influence of steel slag and molybdenum disulfide particles as individual and combined in brake pads formulation to enhance the tribological performance by producing stabilized friction with undulations.
Peer review
The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-06-2020-0216/
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Vijay R., Manoharan S. and Lenin Singaravelu D.
This paper aims to deal with the effect of natural barytes purity levels on the tribological performance of brake pads.
Abstract
Purpose
This paper aims to deal with the effect of natural barytes purity levels on the tribological performance of brake pads.
Design/methodology/approach
In this study, brake pads were developed by varying three different natural barytes without varying other ingredients. The brake pads were developed as per the standard industrial practice. The physical, mechanical and thermal properties of the developed brake pads were tested as per the industrial standards. The tribological properties were analyzed using a full-scale inertia brake dynamometer. Worn surface analysis was done using scanning electron microscope coupled with elemental mapping.
Findings
The experimental results indicate that the brake pads filled with natural barytes 95% purity had good physical, chemical and mechanical properties with stable friction and less wear rate due to reduced impurity level preventing frictional undulations.
Originality/value
This paper explains the effect of the purity level of natural barytes in brake pads formulation to enhance the tribological performance by altering tribofilms and preventing friction undulations.
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Hicri Yavuz and Hüseyin Bayrakceken
The purpose of this paper, brake friction material samples with six different contents were produced using three different fiber types consisting of variable proportions of…
Abstract
Purpose
The purpose of this paper, brake friction material samples with six different contents were produced using three different fiber types consisting of variable proportions of huntite mineral and basalt, glass and steel fibers. The friction properties and formation of the transfer film in these friction materials were investigated.
Design/methodology/approach
Friction materials were produced using a hot molding method from materials containing 10%–15% huntite in varying proportions, consisting of basalt, glass and steel fibers. The densities and hardness values of the samples were measured. Friction tests were performed using a brake pad friction material tester to determine tribological properties. After the friction tests, microscopic examination of the sample surfaces was performed using scanning electron microscope (SEM) and three-dimensional (3D) surface profilometer devices.
Findings
Huntite mineral content and fiber type affected the friction coefficient. With an increase in the amount of huntite, the friction coefficient increased in the friction material samples formed with glass and steel fibers. The fiber type and amount of huntite also affected the transfer film formation. The surface roughness values of all the friction materials decreased with an increase in the amount of huntite. The surface roughness values of the samples with glass fibers were higher than those of other samples.
Originality/value
The importance of using huntite minerals and different fiber types in automotive brake friction materials is emphasized. This will help industrial companies and academics study the tribological properties of friction materials.
Baskara Sethupathi P. and Chandradass J.
This study aims to compare the influence of different solid lubricants on the friction stability of a non-asbestos disc brake pad.
Abstract
Purpose
This study aims to compare the influence of different solid lubricants on the friction stability of a non-asbestos disc brake pad.
Design/methodology/approach
Three brake pads were developed using three lubricants, namely, non-asbestos brake pad with sulfide mix (NASM), non-asbestos brake pad with bismuth sulfide (NABS) and non-asbestos brake pad with molybdenum disulfide (NAMO). Sulfide mix was indigenously developed by physically mixing friction modifiers, alkaline earth chemicals and various metallic sulfides homogeneously dispersed in graphite medium. The physical, chemical, mechanical and thermal properties of brake pads were characterized as per industrial standards. The tribological performances were studied using the Chase testing machine as SAE-J661-2012. The worn surface of the pads was studied using scanning electron microscope to analyze the dominating wear mechanism.
Findings
NASM was excellent in fade as well as wear resistance. NABS was better from a wear point of view, but fade resistance was moderate despite its higher cost. NAMO fared average in fade and wear despite its excellent dry lubricating properties. NASM was excellent in terms of fade as well as wear resistance.
Originality/value
Among the selected metal sulfides, the indigenously developed sulfide mix was better than the other two sulfides, which indicates that the synergetic effect of metal sulfides was always preferable to the individual sulfides.
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Mohd Fadzli Bin Abdollah, Hilmi Amiruddin and Mohamad Jabbar Nordin
This study aims to scrutinise the impact of fibre length and its composition on the tribological attributes of oil palm fibre (OPF) polymeric composite as an alternative brake…
Abstract
Purpose
This study aims to scrutinise the impact of fibre length and its composition on the tribological attributes of oil palm fibre (OPF) polymeric composite as an alternative brake friction material.
Design/methodology/approach
Fabrication of the sample was conducted by using a hot-compression method. The tribological test was carried out by deploying a ball-on-disk tribometer. Analysis of the data was then done by using the Taguchi approach as well as analysis of variance.
Findings
The results indicated that all design variables (fibre composition, length and treatment) are not statistically significant, as all p-values are greater than 0.05. Remarkably, irrespective of the fibre treatment, the wear rate and coefficient of friction (COF) distribution suggested that a smaller fibre length with a high fibre composition might enhance the composite’s tribological performance with COF of 0.4 and wear rate below than 1 × 10–9 mm3/Nm. The predominant wear mechanisms were identified as micro-cracks, fine grooves and fibre debonding.
Research limitations/implications
In this study, all-inclusive scrutiny needs to be carried out for further exploration.
Originality/value
The main contribution and novelty of this study are opening a new perspective on the formulation of new substances from bio-based material (i.e. OPF) that possess superior tribological characteristics for friction-based applications.
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İlker Sugözü, Cengiz Öner, İbrahim Mutlu and Banu Sugözü
The purpose of this study was to investigate the use of boric acid as a friction modifier material in brake friction composites and to determine the effect of heat treatment…
Abstract
Purpose
The purpose of this study was to investigate the use of boric acid as a friction modifier material in brake friction composites and to determine the effect of heat treatment applied during production on braking performance.
Design/methodology/approach
The addition of five different amounts of boric acid was balanced with cashew, which is in the friction modifier material group. The samples were produced in the following order: dry mixing, preforming and hot-pressing. The effect of the heat treatment that can be applied after the hot-pressing process on the braking performance was investigated. The tribological and physical properties of the samples were determined using tests performed according to appropriate standards. The microstructures of the friction surfaces were investigated using scanning electron microscopy.
Findings
It was observed that the tribological properties of brake friction composites containing 20% by weight of boric acid were improved. It has also been observed that the heat treatment applied after hot pressing increased the friction coefficient of the samples by 7% on average and decreased the specific wear ratio of the samples. When the surface morphologies of the samples are examined, it is seen that the friction layers of the heat-treated samples are wider, and the microvoids and cracks are reduced.
Originality/value
This study showed that boric acid can be used as a friction modifier in brake friction composites. It also revealed the tribological and physical contribution of the applied heat treatment to the composite. Thus, it guides brake friction composite manufacturers in the industry and researchers working in this field.