D. W. Goodman, Purdue University, West Lafayette, IN; R. Torres, D. I. Bassani, Catholic University of Parana, Curitiba, Brazil; C. Siqueira, Federal University of Paraná, Curitiba, Brazil
In order to determine the wear mechanism of the coated tools in a milling operation three nitride based thin films were deposited on hard metal substrate by cathodic arc evaporation. In the first part of the project thin film characterization was performed, such as coating thickness, nanohardness, roughness and friction coefficient determination. The thickness of the TiN, TiN/TiCN and TiNAl coatings was 2, 2 and 2.7 micrometers, respectively. The friction coefficient of three nitride coatings was determined by the pin on plane technique, the friction coefficient of TiN, TiN/TiCN and TiNAl was situated between 0.5 and 0.6. The nanoindentation characterization showed that the hardness of the TiN, TiN/TiCN and TiNAl was 20, 22 and 25 GPa, respectively. In the second part of this project each PVD deposited tool machined 400 parts per cutting edge in a dry milling operation. The machined parts were made of SAE/AISI 8620 steel. The wear mechanism was evaluated in the cutting edge of the milling tool covered with TiN, TiN/TiCN and TiNAl. The results showed that the worn area for TiN thin film is larger in comparison with the other two thin films. The TiN thin film showed thermal cracks as well.
