CrC中间层碳含量对CrC/a-C∶H涂层附着力的影响
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摘要
目的提高氢化非晶碳涂层的附着力,研究不同碳含量的CrC中间过渡层对CrC/a-C∶H涂层附着力的影响。方法用反应磁控溅射结合射频PECVD方法制备CrC/a-C∶H涂层,通过调节C2H2流量(0、10、20、30m L/min)在高速钢基材上获得具有不同碳含量CrC中间层的CrC/a-C∶H涂层。用压痕法和划痕法测量涂层的附着力,并用拉曼光谱、原子力显微镜、扫描电镜和纳米压痕等方法对涂层进行表征。结果随着中间层CrC碳含量的增加,涂层的附着力先增加后减小,当C2H2流量为20 mL/min时,CrC/a-C∶H涂层具有最大的附着力,划痕附着力为70.5 N,压痕附着力为HF1,此时涂层的硬度为23.4 GPa,表面光洁度为RMS36.9 nm。通过高斯曲线拟合拉曼图谱得到ID/IG为0.54,G峰位置在1535.9 cm~(-1)。扫描电镜观察结果表明,CrC/a-C∶H涂层有两个明显的界面,即基材/CrC中间层界面与CrC中间层/a-C∶H顶层界面,中间层CrC为柱状晶结构,a-C∶H顶层为玻璃态。结论 CrC中间层碳含量对CrC/a-C∶H涂层的附着力有显著影响,具有合适碳含量的CrC中间层有助于提高涂层的附着力,当含碳量过高时,中间层会由晶态转变为非晶态,不利于承载来自于a-C∶H顶层的薄膜内应力,导致CrC/a-C∶H涂层附着力急剧下降。CrC/a-C∶H涂层附着失效主要发在CrC中间层/a-C∶H顶层界面。CrC中间层碳含量影响CrC/a-C∶H涂层的光洁度,相同a-C∶H涂层工艺条件下,光滑涂层具有更好的附着力。
The work aims to improve the adhesion of hydrogenated amorphous carbon coating on substrate and study the effect of CrC interlayer with different carbon contents on the adhesion of CrC/a-C∶H coating. The CrC/a-C∶H coatings were prepared by reactive magnetron sputtering combined with RF PECVD. The C_2H_2 flow rate was adjusted(0, 10, 20, and 30 mL/min) to obtain CrC/a-C∶H coatings with different carbon contents in the CrC interlayer. The adhesion of the coating was measured by indentation and scratching. The coatings were characterized by Raman, AFM, SEM and Nano-indentation methods. With the increasing of the C content in the CrC interlayer, the adhesion of the coating first increased and then decreased. When the C_2H_2 flow rate was 20 mL/min, the CrC/a-C∶H coating had the highest adhesion force; the scratch adhesion force was 70.5 N and the indentation adhesion force was HF1. At this point, the hardness of the coating was 23.4 GPa and the RMS surface roughness was 36.9 nm. The ID/IG obtained by Gaussian curve fitting Raman map was 0.54 and the G peak position was 1535.9 cm~(-1). The SEM image showed that the coatings had two clear observable interfaces, the substrate/CrC interlayer interface and the CrC interlayer/a-C∶H top layer interface. The CrC interlayer of the CrC/a-C∶H coating was a columnar crystal structure and the top layer a-C∶H was amorphous. The carbon content of CrC interlayer has a significant effect on the adhesion of CrC/a-C∶H coating. The appropriate carbon content of CrC interlayer helps to improve the adhesion of the coating. When the carbon content is too high, the interlayer will change from crystalline to amorphous, which is not conducive to carrying the internal stress of the film from a-C∶H top layer, resulting in a sharp decline in the adhesion of CrC/a-C∶H coating. The adhesion failure of CrC/a-C∶H coating mainly occurs at the interface of CrC interlayer/a-C∶H top layer. The carbon content of the CrC interlayer affects the roughness of the CrC/a-C∶H coating. The adhesion of the coating is linearly related to the roughness. With different CrC interlayers for the same a-C∶H layer, smoother CrC/a-C∶H coatings have higher adhesion force.
The work aims to improve the adhesion of hydrogenated amorphous carbon coating on substrate and study the effect of CrC interlayer with different carbon contents on the adhesion of CrC/a-C∶H coating. The CrC/a-C∶H coatings were prepared by reactive magnetron sputtering combined with RF PECVD. The C_2H_2 flow rate was adjusted(0, 10, 20, and 30 mL/min) to obtain CrC/a-C∶H coatings with different carbon contents in the CrC interlayer. The adhesion of the coating was measured by indentation and scratching. The coatings were characterized by Raman, AFM, SEM and Nano-indentation methods. With the increasing of the C content in the CrC interlayer, the adhesion of the coating first increased and then decreased. When the C_2H_2 flow rate was 20 mL/min, the CrC/a-C∶H coating had the highest adhesion force; the scratch adhesion force was 70.5 N and the indentation adhesion force was HF1. At this point, the hardness of the coating was 23.4 GPa and the RMS surface roughness was 36.9 nm. The ID/IG obtained by Gaussian curve fitting Raman map was 0.54 and the G peak position was 1535.9 cm~(-1). The SEM image showed that the coatings had two clear observable interfaces, the substrate/CrC interlayer interface and the CrC interlayer/a-C∶H top layer interface. The CrC interlayer of the CrC/a-C∶H coating was a columnar crystal structure and the top layer a-C∶H was amorphous. The carbon content of CrC interlayer has a significant effect on the adhesion of CrC/a-C∶H coating. The appropriate carbon content of CrC interlayer helps to improve the adhesion of the coating. When the carbon content is too high, the interlayer will change from crystalline to amorphous, which is not conducive to carrying the internal stress of the film from a-C∶H top layer, resulting in a sharp decline in the adhesion of CrC/a-C∶H coating. The adhesion failure of CrC/a-C∶H coating mainly occurs at the interface of CrC interlayer/a-C∶H top layer. The carbon content of the CrC interlayer affects the roughness of the CrC/a-C∶H coating. The adhesion of the coating is linearly related to the roughness. With different CrC interlayers for the same a-C∶H layer, smoother CrC/a-C∶H coatings have higher adhesion force.
引文
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[14]CATHERINE Y.Preparation techniques for diamond-like carbon[C]//Diamond and diamond-like films and coatings.New York:Plenum press,1991:193-228.
[15]FERRARI A C,ROBERTSON J.Interpretation of Raman spectra of disordered and amorphous carbon[J].Physical review B:Condensed matter,2000,61(20):14095-14107.
[16]CASIRAGHI C,FERRARI A C,ROBERTSON J.Raman spectroscopy of hydrogenated amorphous carbons[J].Physical review B:Condensed matter,2005,72(8):85401-85409.
[17]MARTíNEZ M,LóPEZ C,FERNáNDEZ A,et al.Influence of the microstructure on the mechanical and tribological behavior of TiC/a-C nanocomposite coatings[J].Thin solid films,2009,517(5):1662-1671.
[18]KEUNECKE M,BEWILOGUA K,BECKER J,et al.CrC/a-C:H coatings for highly loaded,low friction applications under formulated oil lubrication[J].Surface and coatings technology,2012,207:270-278.
[19]WOLFGANG T,NELSON F L D,DOMINIC S.Tribomechanical properties of CrC/a-C thin films sequentially deposited by HIPIMS and MFMS[J].Surface and coatings technology,2018,335:173-180.
[2]BEWILOGUA K,HOFMANN D.History of diamond-like carbon films-from first experiments to worldwide applications[J].Surface and coatings technology,2014,242(15):214-225.
[3]HéAU C.DLC films in mechanical,manufacturing industry[C]//Tribology of diamond-like carbon films-fundamentals and applications.New York:Springer,2008:469-483.
[4]HOLLECK H.Material selection for hard coatings[J].Journal of vacuum science and technology,1986,4(6):2661-2669.
[5]CEMIN F,BIM L T,LEIDENS L M,et al.Identification of the chemical bonding prompting adhesion of a-C∶Hthin films on ferrous alloy intermediated by a SiCx∶Hbuffer layer[J].ACS applied materials and interfaces,2015,7(29):15909-15917.
[6]PAULEAU Y.Residual stresses in DLC films and adhesion to various substrates[C]//Tribology of diamond-like carbon films-fundamentals and applications.New York:Springer,2008:102-136.
[7]VOEVODINA A,CAPANOM A,LAUBES J P,et al.Design of a Ti/TiC/DLC functionally gradient coating based on studies of structural transitions in Ti-C thin films[J].Thin solid films,1997,298(1-2):107-115.
[8]STüBER M,ULRICH S,LEISTE H,et al.Graded layer design for stress-reduced and strongly adherent superhard amorphous carbon films[J].Surface and coatings technology,1999(116-119):591-598.
[9]LEE K R,EUN K Y,KIM I,et al.Design of W buffer layer for adhesion improvement of DLC films on tool steel[J].Thin solid films,2000(377-378):261-268.
[10]VETTER J.60 years of DLC coatings:historical highlights and technical review of cathodic arc processes to synthesize various DLC types,and their evolution for industrial applications[J].Surface and coatings technology2014,257(25):213-240.
[11]BUGAEV S P,PODKOVYROV V G,OSMOKOV K V,et al.Ion assisted pulsed magnetron sputtering deposition of Ta-C films[J].Thin solid films,2001,389(1-2):16-26.
[12]DEKOVEN B M,WARD P R,WEIS R E,et al.Carbon thin film deposition using high power pulsed magnetron sputtering[J].SVC annual technical conference proceedings,2003(46):158-165.
[13]SARAKINOS K,BRAUN A,ZILKENS C,et al.Exploring the potential of high power impulse magnetron sputtering for growth of diamond-like carbon films[J].Surface and coatings technology,2012,206(10):2706-2710.
[14]CATHERINE Y.Preparation techniques for diamond-like carbon[C]//Diamond and diamond-like films and coatings.New York:Plenum press,1991:193-228.
[15]FERRARI A C,ROBERTSON J.Interpretation of Raman spectra of disordered and amorphous carbon[J].Physical review B:Condensed matter,2000,61(20):14095-14107.
[16]CASIRAGHI C,FERRARI A C,ROBERTSON J.Raman spectroscopy of hydrogenated amorphous carbons[J].Physical review B:Condensed matter,2005,72(8):85401-85409.
[17]MARTíNEZ M,LóPEZ C,FERNáNDEZ A,et al.Influence of the microstructure on the mechanical and tribological behavior of TiC/a-C nanocomposite coatings[J].Thin solid films,2009,517(5):1662-1671.
[18]KEUNECKE M,BEWILOGUA K,BECKER J,et al.CrC/a-C:H coatings for highly loaded,low friction applications under formulated oil lubrication[J].Surface and coatings technology,2012,207:270-278.
[19]WOLFGANG T,NELSON F L D,DOMINIC S.Tribomechanical properties of CrC/a-C thin films sequentially deposited by HIPIMS and MFMS[J].Surface and coatings technology,2018,335:173-180.