چكيده به لاتين
The purpose of this study was to create the necessary knowledge to design compounds of copper-free friction materials using environmentally friendly materials. The proposed base friction material of the low-metal composite type (containing less than 20% by weight of steel fibers) has been improved. Using the error test method, 5 compounds were presented as the base compound, three compounds including 2, 4, and 6% by weight of platelet potassium titanate and at the end of the compound containing 6% of potassium titanate and ceramic fibers, respectively, which contained fibers. Ceramics and potassium titanate have shown the best performance among other compounds in terms of frictional properties. The friction performance of the presented composites was evaluated by friction test on laboratory scale according to SAE J661 or ISIRI-586-2 standard. After performing the functional test, the wear mechanism of the composite was investigated using a scanning electron microscope, and the necessary graphic models were presented to explain the structure of composite worn surfaces without copper. Analysis of the wear mechanism using scanning electron microscopy showed that the sample containing ceramic fibers and potassium titanate had a better performance in the formation of contact plates and more stable friction film and resulted in better friction performance than other compounds. The formation of a stable wear mechanism including friction film, contact plates, and micro-slots seems to be the main factor in controlling friction performance and stability of friction film. In the sample containing ceramic fibers and potassium titanate, by optimizing the components of the previous four compounds and adding ceramic fibers along with potassium titanate, showed stable and optimal frictional performance. The ability to form a stable friction film on the contact plates plays an important role in controlling and reducing the wear rate. In such a way that changes in the nucleation process, growth, and degradation of the friction film cause noticeable changes in the fluctuations of friction coefficient and wear rate. Scanning electron microscopy images of more contact plates next to the micro-slits were shown in samples containing ceramic fibers and potassium titanate, and graphical models of the relationships between the friction film formation process and friction changes were presented.
