The study of influence of the reaction gases ratio at the Ti–Al–C–N coating deposition on the cutting tool wear resistance

The paper presents the results of the study of the component composition of the reaction gases mixture when synthesizing carbonitride coatings of the Ti–Al–C–N system influencing the cutting tool durability. The coating was applied using the updated unit NNV-6.6-I1 by spraying from two one-component cathodes assisted by the incandescent cathode plasma source. During applying the coating, the mixture of reaction gases of N2 nitrogen and C2H2 acetylene in the ratio of 1:4, 2:3, 3:2, and 4:1 was delivered to the chamber. The paper presents the results of measuring the microhardness of studied specimens, which show that a sample with the coating deposited at the reaction gases ratio of N2:C2H2=2:3 had the largest microhardness value (4870 HV0.05). The paper presents the results of field tests of carbide-tipped tools with the studied coatings. Durability tests identified that a cutter with the coating deposited at the gas ratio of N2:C2H2=4:1 increases the tool durability ten times compared to a cutting tool without coating. Using the electron microscopy method, the authors investigated the chemical composition of the tool cutting face after tests. The analysis of the chemical composition of the surface after cutting showed that the content of coating elements on the surface of the sample with a coating deposited at the 4:1 ratio of the reaction gases of nitrogen and acetylene was considerably higher than that of other studied coatings, which indicates the less coating wear. However, ferrum is present in some areas of the cutting face, which says about the adhesion of treated material to the tool.