Abstract
Abrasive tools consist of abrasive grains, binder and pores. Binders are the matrix of the material and may be of the metallic, vitrified or resin type. The wide use of polymeric materials (resinoid) is due to their low cost and excellent mechanical properties. The grain has the function of roughing the material, the binder, on the other hand, has the characteristics of ensuring grain adhesion and the pores in the structure are responsible for cooling the abrasive tool. In this work, we report the preparation and evaluation of the mechanical characteristics of resin bond composite abrasives with different structures based on the porous concentration. The composite abrasives were made with phenolic resin and alumina grains. Four different structures were studied from 10 to 30% of porous volume fraction with 50% of grain volume fraction. The concentration of porous and bond in the structure composition were employed to compare the mechanical performance of the prepared composite abrasive. To evaluate the mechanical properties of composites, Impact strength, Young’s Modulus by impulse excitation and flexural strength were realized. It was observed that as the porosity is higher, the impact resistance (absorbed energy) is lower, which confirms the lower resistance produced by the surface area contact (grain/binder) and a greater accumulation of tension in the binder material, the higher porosity value, higher the flexural strength value until 20% of porosity. Samples with higher volumes level of porosity presented lower Young’s Modulus but the presence of pores produced by volatiles by-products (mainly water) should act as stress concentrators, thus favoring lower mechanical properties at the resin-grain interface.
