| AlCr(Ti)SiN coating possesses excellent mechanical properties,high temperature oxidation resistance and corrosion resistance,which is widely used as a high-performance coating.When it is coated on the surface of the tool to cut difficult-to-machine materials,its inferior friction performance accelerates the wear between the tool and the workpiece,and reduces the service life of the tool.In this paper,by adding Mo lubricating phase to AlCr(Ti)SiN coating,adjusting the content of the lubricating phase to optimize the coating performance,and exploring the influence of the content of the lubricating phase on the microstructure,mechanical properties,and tribological properties of the coating.Use vacuum heat treatment to improve coating defects and strengthen coating performance,and compare the cutting performance of self-lubricating tools through cutting experiments.The AlCrSiN/Mo self-lubricating coating is prepared by high-power pulsed magnetron sputtering technology and pulsed DC sputtering technology.The content of the lubricating phase Mo in the coating is controlled by controlling the sputtering power of the target material.With the increase of the Mo content,the crystallinity of the coating gradually increases,the size of surface grains and cross-sectional columnar crystals gradually increase,and the diffraction peaks shift to high angles.When the power of the high-power Al Cr Si target is 1.2 k W and the power of the DC Cr Mo target is 0.4 k W,the Mo content reachs 21.3 at.%.At this time,the hardness and elastic modulus of the coating are relatively high,respectively 17.54 GPa and 295.09 GPa;corresponding to the maximum criticality load is 67.62 N;at this time,the tribological performance of the coating is the best,the wear rate is about 7.97×10-4?m3/(N·?m),the friction coefficient is 0.54,and the overall performance of the coating is the best.At this time,the characteristic values H/E and H3/E*2are also the largest.At high temperatures,the AlCrSiN/Mo self-lubricating coating exhibits better tribological properties than the Al Cr Si N coating.Al Cr Ti Si N/Mo self-lubricating coatings are prepared under different Cr Mo target powers.The Mo content increases from 0 at.%to 4.3 at.%,and the preferred orientation transitioned from(111)to(200)crystal planes.When the power of the Cr Mo target is 0.6 k W,the density of the coating is the best,the mechanical properties are the best,the maximum hardness is 16.08 GPa,the critical load is 59.48 N,and the characteristic values H/E and H3/E*2are the highest at 0.05and 0.032.As the power of the Cr Mo target increases,the friction coefficient of the coating shows a gradual decrease.The minimum friction coefficient is 0.54.When the power of the Cr Mo target is 0.6 k W,the coating has the best wear resistance,and the minimum wear rate is8.10×10-3?m3/(N·?m).After vacuum heat treatment,the structure and performance of AlCrSiN/Mo have been improved to a certain extent.After the heat treatment,the crystallinity of the coating increases,the surface particle size gradually increases,and the metastable phase fcc-(Al,Cr)N solid solution phase decomposes into hcp-Al N and hcp-Cr2N phases.The hardness,wear reduction and wear resistance of the coating have been improved.Due to the difference in thermal expansion coefficient and other factors,the bonding strength of the film base has deteriorated.When the annealing temperature is 700?,the hardness of the coating is the highest 23.01 GPa,the friction coefficient and the wear rate are both 0.56 and 1.67×10-3?m3/(N·?m)respectively.Through the comparison of the cutting performance of three kinds of tools,namely uncoated,Al Cr Si N,and AlCrSiN/Mo coated tools,the cutting life of AlCrSiN/Mo coated tools is the highest,which is twice and 1.2 times that of uncoated tools and Al Cr Si N coated tools,respectively;The cutting temperature is the lowest during the same cutting time;After 30minutes of cutting,the wear of the AlCrSiN/Mo coated flank and the integrity of the bottom edge are better than those of the other two milling cutters. |
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