2016 年 82 巻 2 号 p. 198-204
We have attempted to improve performance of cutting tools by coating on tool edge surface with a hard and lubricious thin film. In this work, B-C coatings have been prepared on silicon and tungsten carbide substrates by DC magnetron sputtering with a sintered B4C target. For obtaining excellent frictional properties in the B-C coatings, CH4 gas was introduced as a plasma gas Nano-indentation studies showed that the CH4 introduction in the film formation process led to a lower hardness of the film. On the other hand, the adhesive strength to the substrate was increased by the CH4 introduction in the film formation process. Furthermore, the frictional properties of the B-C coating against a steel ball in an ambient atmosphere were improved by CH4 addition and their friction coefficients reduced from 1.0 to 0.4. Then, we created B-C coated tools, and evaluated the cutting performance against a stainless steel by using a high speed precision lathe. The B-C coated tool showed better cutting performance than non coated tool. However, the B-C coating was peeled off from the tool edge at the cutting length of 1000 m in a dry condition.