Desenvolvimento de material para ferramenta de corte cerâmica autolubrificada

Abstract

Due to growing concern about the risks caused by the use of cutting fluid in the machining process, substitution alternatives are sought, which is the case of the use of self-lubricated cutting tools. However, the insertion of a lubricating material in the cutting tool matrix modifies the physical-mechanical properties. Therefore, it is necessary to know the properties and behavior of materials that will be used for this purpose, once that they influence directly on the tool performance, its useful life, the wear and the cost of the process. Given this, the work has been aimed to develop and evaluate a self-lubricating cutting tool with alumina matrix (Al2O3) and molybdenum disulfide (MoS2), Graphite and Barium Fluoride (BaF2) as solid lubricants. The samples were developed from pure alumina and with compositions containing 5, 10 and 15% of each solid lubricant in the matrix. The powders were processed through the grinding and sintering via SPS. After, the compacted material was characterized regarding microhardness, hardness, fracture toughness, and roughness. The ability to lubricate was investigated in a pin-on-disc tribological test. The fracture surfaces and wear were evaluated by scanning electron microscopy. As results, it was observed that with the increase of the insertion of solid lubricant there was a decrease in the values of microhardness, hardness, and fracture toughness. The best tribological results were obtained for samples containing 15% of MoS2.