الفهرس 
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Abstract
In the present work, the friction material composites were proposed to be used as brake lining materials. The composites were reinforced by agricultural fibers of corn, palm, and sugar bars.
The proposed composites materials are environmentally friendly friction material for brake lining and clutch facings. The conventional brake lining material based on asbestos that causes serious lung diseases and being cancerous potential was replaced by the proposed composites.
Agricultural wastes of sugar bars, corn, and palms firewood are prepared to obtain fine sticks of dimension less than 5 mm. The fiber materials were mixed by commercial carbon, barium sulfate, silica and metallic powder in defined ratios and then added to phenol formaldehyde. The specimen composite was pressed in the die at temperature 100Co. The produced specimens were subjected to machining processes to obtain the cylindrical form of 8 mm diameter.
The test rig was manufactured in the workshop of high institute of energy –Aswan. It consists of a rotating flat disc made of alloy steel, with an outside diameter of 250 mm and 16 mm thickness. A heating coil was used to increase the experimental temperature surrounding the disc.
The tests investigated the effect of agriculture fiber wastes (corn fiber, sugar bars fibers, palms fibers) content on the friction of coefficient and wear also, the effect of water dilution on wear was investigated. Wear mechanisms of proposed composites were characterized by scanning electronic microscopy. The tribological properties of the proposed composites materials were compared to three commercial brakes lining “brake lining (A), (B), and (C). Those were made in Turkey, Egypt, and China respectively.
Based on the experimental results it was found that, addition of agriculture fiber wastes (corn fiber, sugar bars fibers, palms fibers) into composites materials improved the friction coefficient and decreases the wear. The corn fiber was more compatible with aluminum powder where it gives highest friction coefficient and low wear, while it was incompatible with iron powder. The results shows the increase of the friction coefficient of high metallic powder content for each metallic powders. Friction coefficient of the composites decreased with increasing agriculture fiber content in present of water contamination on sliding surface, while composites of medium and low agriculture fiber content of high metallic powder content reveal a general trend for friction coefficient increase. The proposed composite materials give best results for wear at room temperature, while it give undesirable results for wear at high temperature when compared with commercial brake lining.
Wear of composites increased with increasing agriculture fiber content at high temperature, which may be attributed to the low resistance of agriculture fiber to withstand high temperature. Wear of composites decreased with increasing metallic powder content, which may be attributed to the increasing of the heat transfer from the composite.