A STUDY OF THE DURABILITY OF A PAPER-BASED FRICTION MATERIAL INFLUENCED BY POROSITY

The friction performance and thermal resistance of paper-based oil immersed friction materials are influenced by the material structure formed as a result of the combination of porosity and resiliency. In this paper, the effects of porosity on the thermal durability of paper-based friction materials were studied, of which the contents are varied but the geometries are the same as used in real applications. The relationship between the degree of carbonization and the durability was discussed in several terms of mechanical property changes of the material. The friction and thermal durability tests were conducted by using an SAE No. 2 apparatus under a repeated engage-disengagement condition. To obtain the thermal durability performance the sliding surface temperature was also measured, Coefficients of friction of the low porosity material tend to decrease as the test cycle increases. And the total thickness loss of the low porosity material after durability test is bigger than that of the high porosity material. These durability performances were well correlated with the mechanical and physical property changes of the material, that is, variations of carbonization degree, permeability and hysteresis loss energy.