Microstructure and mechanical properties of Ti/TiN/TiAlN composite coating prepared by arc ion plating and magnetron sputtering composite technology..
Using magnetron sputtering and arc ion plating technology, a Ti/TiN/TiAlN composite coating was prepared on the high-speed steel substrate. Using scanning electron microscope, X-ray diffractometer, micro-hardness tester, micro-scratch tester and other methods, the influence of plating conditions on the morphology, structure and mechanical properties of the composite coating was studied. The results show that the transition layer of ion plating has an important influence on the microstructure and mechanical properties of the magnetron sputtering coating. For example, the composite film prepared by the newly developed AIP+MS technology has higher hardness, better wear resistance, smoother surface and stronger film-base bonding force (greater than 30N) than the film prepared by AIP or MS technology. . Because the "large particles" on the surface of the TiN transition layer of arc ion plating will crystallize and grow when the TiAlN film is deposited by magnetron sputtering, the microstructure is similar to the TiAlN on the film, which improves the combination with the surrounding film. The negative effect of "large particles" on the surface of the TiN transition layer is greatly weakened.
In the machinery manufacturing industry, most of the mechanical parts are currently made by cutting. Coated tools can improve processing efficiency and accuracy, extend the service life of the tools, and reduce processing costs. More than 80% of cutting tools use coated tools. At present, ion plating and magnetron sputtering technology are widely used to prepare coated tools. Ion plating technology has the advantages of high ion energy, high ionization rate, dense film layer and strong adhesion. However, the film prepared by ion plating easily contains micro-sprayed particles, which affects the surface roughness and destroys the continuity of the film; The surface of the film prepared by magnetron sputtering deposition technology is flat and dense, without obvious holes and large particles during arc deposition. Vacuum Technology Network (http://www.chvacuum.com/) believes that magnetron sputtering also has disadvantages: the target material is not uniformly etched and the target material utilization rate is small. At present, high-speed steel has the advantages of low price, recyclability and other advantages for complex cutting tools, which has gradually increased its application, but its wear resistance is not ideal enough and its service life is also low.
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TiN coating has high hardness, high wear resistance, low friction coefficient and good chemical stability. TiAlN film has higher hardness, high temperature oxidation resistance, thermal fatigue performance, wear resistance and other excellent characteristics. The composite film can not only make full use of the original good comprehensive mechanical properties of the single-layer film, but also improve the film's hardness, toughness and high-temperature oxidation resistance. It is one of the important development directions for improving the performance of hard films. At present, ion plating TiN film has been widely used in tool and mold coatings, but the problem of "large particles" on the surface of the film prepared by ion plating technology limits its application in the field of high surface quality requirements. This article combines the advantages of arc ion plating technology with high ionization rate, high incident particle energy, uniform film layer and smooth surface of magnetron sputtering technology, while taking into account the difference in the thermal expansion coefficient of the material (high-speed steel: ~11.7×10-6/K , Ti coating: 10.8×10-6/K, TiN coating: 9.4×10-6/K, TiAlN coating: 7.5×10-6/K), Ti/TiN is deposited on the surface of high-speed steel tools /TiAlN composite coating. Using this method not only can effectively improve the surface quality of the film prepared by the arc ion plating technology, but also provides a preparation method with practical production significance.
1. Experiment content
1.1. Experimental equipment and materials
In this experiment, AIP-01 type multi-arc ion coating machine and JGP-560b type magnetron sputtering coating machine were used for coating. A titanium target with a purity of 99.99% was used as the target material of the ion coating machine. Titanium aluminum alloy target material (Ti/Al atomic ratio 50:50) As the sputtering target material of the magnetron sputtering coating machine, 99.99% pure Ar gas is used as the working gas, 99.99% pure N2 is used as the reactive gas, and the matrix is W6Mo5Cr4V2 high-speed steel (abbreviated as M2, quenching + tempering, HRC60), the sample size is 10mm×10mm×5mm.
1.2. Experimental method
Preparation process: After grinding and polishing the surface of M2 steel substrate, ultrasonic cleaning with acetone and absolute ethanol was used → Ti layer and TiN layer were plated in sequence in ion coating machine → Coating samples were taken out → In magnetron sputtering equipment for plating Cover TiAlN layer → to obtain Ti/TiN/TiAlN composite coating. Before preparing the composite coating, first optimize the process of preparing TiAlN film by magnetron sputtering. Based on the equipment characteristics of the JGP-560b magnetron sputtering coating machine, fix the optimized coating process parameters such as deposition temperature, working pressure, and target source power. Under such conditions, by changing the nitrogen flow rate, the effect on the performance of the TiAlN film was studied. The coating process is shown in Table 1.
Table 1 TiAlN coating process prepared by magnetron sputtering technology
Preparation of TiAlN Coating Process by Magnetron Sputtering Technology
When preparing Ti/TiN/TiAlN composite coatings, first prepare Ti/TiN transition layers of different thicknesses, and then plate the optimized TiAlN coating on the appropriate transition layer. The preparation process of the composite coating is shown in Table 2. The samples numbered 2-1#, 2-2#, and 2-3# are ion-plated TiN transition layers. The deposition time is 5, 15, and 30 minutes, respectively, and then the TiAlN surface coating is coated by magnetron sputtering. No. 2-4# sample is ion-plated with TiN transition layer for 30 minutes, in situ ion cleaning for 3 minutes, followed by magnetron sputtering plating TiAlN surface coating, the difference between No. 2-5# and 2-4# sample lies in magnetron sputtering When the TiAlN film was shot, the nitrogen flow rate was 4mL/min.
Table 2 Process of preparing Ti/TiN/TiAlN composite coating by ion plating and magnetron sputtering composite technology
Process for preparing Ti/TiN/TiAlN composite coating by composite technology of ion plating and magnetron sputtering
1.3, performance test method
The HV-1000 microhardness tester was used to measure the microhardness of the coating, and the multi-point measurement method was used to obtain the average value. The loading load was 25g and the loading time was 15s; the film base bonding force was measured by the MST scratch tester. The instrument has a diamond indenter tip radius R=0.1mm and a maximum load of 30N. It comprehensively evaluates the film-base adhesion through optical microscopic observation of acoustic signals, friction, coefficient of friction and in-situ scratches. During the scratch experiment, as the loading force of the test needle increases, the film will crack or fall off a little, but this does not necessarily lead to the failure of the film. When testing the bonding force with this equipment, select the smallest film that starts to break The load is the low critical load LC1, and the load when the film is completely peeled off is the high critical load LC2. The film-base bonding force of the film should be combined with LC1 and LC2. The existing comparative experimental results show that the critical load measured by this device is equivalent to common literature reports. The radius of the scratch indenter is 1/4 times that of 200μm. Philips X′ymbolbB@Pert X-ray diffraction (XRD) instrument was used to analyze the phase structure of the samples; LEO-1530VP type field emission scanning electron microscope (FESEM) was used to observe the surface and cross-sectional morphology of the film coating and the thickness of the coating.
3. Conclusion
(1) The TiAlN film prepared by magnetron sputtering technology has a surface particle size of 150-200nm, regular shape, uniform size, dense distribution, no defects such as "large particles", and good surface quality; with nitrogen flow during deposition The increase of the film deposition rate decreases, the microhardness decreases, and the film base bonding force increases.
(2) Use magnetron sputtering to coat TiAlN surface coating on the surface of ion-plated TiN film. In the process of film growth, the surface of "large particles" produced by ion plating technology also has film crystal growth and grain structure morphology Similar to the grains on the film, it is tightly combined with the surrounding film structure. The "large particles" are continuous with the TiAlN film on the surface and have a smooth transition. The film of the composite coating is tightly bonded.
(3) The Ti/TiN/TiAlN composite coating prepared by combining arc ion plating technology and magnetron sputtering technology has uniform structure, flat surface, good film-base bonding performance, and film-base bonding force greater than 30N.
Founded in 2015,Zunhua Baorui Titanium Equipment Co.,Ltd. is a manufacturer specializing in pvd vacuum ion coating equipment. The company’s products mainly include large plate coating machine, large tube collating machine, tool coating machine and LOW-E glass production line. Mr.Wang baijiang ,general manager of the company ,has been engaged in vacuum coating industry for more than 30 years. He continuously improve production technology, improve product performance and devote himself to provide customers with better product experience and higher production efficiency.