施加偏压对采用等离子体辅助热丝化学气相沉积法在硬质合金上沉积金刚石/碳化硅/硅化钴复合薄膜的影响
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摘要
金刚石涂层硬质合金是一种出众的刀具材料,将碳化硅掺入金刚石涂层中不仅可以提高涂层的断裂韧性,还能够提高薄膜与基体之间的粘附性。文章采用氢气、甲烷和四甲基硅烷混合气体作为反应气体,用直流等离子体辅助热丝化学气相沉积法在硬质合金基体上沉积金刚石-碳化硅-硅化钴复合薄膜。通过扫描电子显微镜、电子探针显微分析、X射线衍射和拉曼光谱对薄膜的表面形貌、成分以及结构进行了分析,结果显示此复合薄膜中含有金刚石、碳化硅(β-Si C)和硅化钴(Co2Si、Co Si)。复合薄膜的结构和成分可通过调节偏流和气相中四甲基硅烷的浓度来控制,随着偏流的增加,复合薄膜中金刚石晶粒尺寸变大且含量增加,β-Si C的含量减少,因为复合薄膜沉积过程中正偏压促进金刚石的生长,并且增强金刚石的二次形核。虽然电子轰击同时增强了氢气、甲烷和四甲基硅烷的分解,但随着偏流的增加,气相中产生的碳源浓度高于硅源浓度,使金刚石比β-Si C在空间生长上更具有优势。当偏流过高时则形成纯金刚石,不能够同时沉积金刚石、β-Si C和硅化钴三种物质。通过调节偏压和气体成分,金刚石和碳化硅在复合薄膜中的分布得以控制。该工作有助于理解和控制复合材料和超硬薄膜的生长,所产生的复合薄膜可用于提高金刚石涂层刀具切削性能。
Diamond coated hard metal is an outstanding cutting material for manufacturing. By adding Si C to the diamond coating material, not only the surface toughness but also the film adhesive strength can be improved. Diamond/β-Si C/cobalt silicide composite films were deposited on Co-cemented tungsten carbide(WC-Co) substrates by direct current plasma assisted hot filament chemical vapor deposition using a gas mixture of hydrogen, methane and tetramethylsilane. Scanning electron microscopy, electron probe microanalysis, X-ray diffraction and Raman scattering analyses were carried out to characterize the surface morphology, composition and structure of the deposited films. The results revealed that the composite films consist of diamond, β-Si C and cobalt silicides(Co2Si, Co Si). The structure and composition of the composite films can be controlled by adjusting bias current and tetramethylsilane concentration in the gas phase. With the increase of bias current, the grain size and content of diamond also increase, while the content of β-Si C decrease. Since bias current enhances the secondary nucleation and growth of diamond. Although the dissociation of hydrogen, methane and tetramethylsilane are all enhanced by electron bombardment during the biasing process, the concentration of produced C sources is much higher than that of Si sources with the increase of bias current. Then the growth of diamond becomes more competitive than that of β-Si C. The bias current cannot be too high to deposit the three substances of diamond, β-Si C and cobalt silicides. By adjusting bias and gas composition, the distribution of diamond and β-Si C in the composite films was manipulated. These results demonstrated the significance to understand and control the growth of composite materials and super hard thin films. Such composite films can be utilized to improve the cutting performance of diamond coated cutting tools.
Diamond coated hard metal is an outstanding cutting material for manufacturing. By adding Si C to the diamond coating material, not only the surface toughness but also the film adhesive strength can be improved. Diamond/β-Si C/cobalt silicide composite films were deposited on Co-cemented tungsten carbide(WC-Co) substrates by direct current plasma assisted hot filament chemical vapor deposition using a gas mixture of hydrogen, methane and tetramethylsilane. Scanning electron microscopy, electron probe microanalysis, X-ray diffraction and Raman scattering analyses were carried out to characterize the surface morphology, composition and structure of the deposited films. The results revealed that the composite films consist of diamond, β-Si C and cobalt silicides(Co2Si, Co Si). The structure and composition of the composite films can be controlled by adjusting bias current and tetramethylsilane concentration in the gas phase. With the increase of bias current, the grain size and content of diamond also increase, while the content of β-Si C decrease. Since bias current enhances the secondary nucleation and growth of diamond. Although the dissociation of hydrogen, methane and tetramethylsilane are all enhanced by electron bombardment during the biasing process, the concentration of produced C sources is much higher than that of Si sources with the increase of bias current. Then the growth of diamond becomes more competitive than that of β-Si C. The bias current cannot be too high to deposit the three substances of diamond, β-Si C and cobalt silicides. By adjusting bias and gas composition, the distribution of diamond and β-Si C in the composite films was manipulated. These results demonstrated the significance to understand and control the growth of composite materials and super hard thin films. Such composite films can be utilized to improve the cutting performance of diamond coated cutting tools.
引文
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[5]Mandal S,Thomas ELH,Jenny TA,et al.Chemical nucleation of diamond films[J].ACS Applied Materials&Interfaces,2016,8(39):26220-26225.
[6]Park BS,Baik YJ,Lee KR,et al.Behaviour of Co binder phase during diamond deposition on WC-Co substrate[J].Diamond&Related Materials,1993,2(5):910-917.
[7]Dumpala R,Kumar N,Kumaran CR,et al.Adhesion characteristic of nano-and microcrystalline diamond coatings:Raman stress mapping of the scratch tracks[J].Diamond&RelatedMaterials,2014,44(4):71-77.
[8]Cui Y,Wang W,Shen B,et al.A study of CVD diamonjd deposition on cemented carbide ballend milling tools with high cobalt content using amorphous ceramic interlayers[J].Diamond&Related Materials,2015,59:21-29.
[9]Hei H,Ma J,Li X,et al.Preparation and performance of chemical vapor deposition diamond coatings synthesized onto the cemented carbide micro-end mills with a SiC interlayer[J].Surface&Coatings Technology,2015,261:272-277.
[10]Lin CR,Kuo CT,Chan RM.Improvement in adhesion of diamond films on cemented WC substrate with Ti-Si interlayers[J].Diamond&RelatedMaterials,1998,7(11-12):1628-1632.
[11]Haubner R,Lux B.Diamond deposition on steel substrates using intermediate layers[J].International Journal of Refractory Metals&Hard Materials,2006,24(5):380-386.
[12]Li YS,Tang Y,Yang Q,et al.Al-enhanced nucleation and adhesion of diamond films on WC-Co substrates[J].International Journal of Refractory Metals&Hard Materials,2008,26(5):465-471.
[13]Manaud JP,Poulon A,Gomez S.A comparative study of CrN,ZrN,NbN and TaN layers as cobalt diffusion barriers for CVD diamond deposition on WC-Co tools[J].Surface&Coatings Technology,2007,202(2):222-231.
[14]Xu F,Xu JH,Yuen MF,et al.Adhesion improvement of diamond coatings on cemented carbide with high cobalt content using PVD interlayer[J].Diamond&Related Materils,2013,34(2):70-75.
[15]Polini R,Barletta M.On the use of CrN/Cr and CrN interlayers in hot filament chemical vapour deposition(HF-CVD)of diamond films onto WCCo substrates[J].Diamond&Related Materils,2008,17(3):325-335.
[16]Qin F,Chou YK,Dohlen D,et al.Coating thickness effects on diamond coated cutting tools[J].Surface&Coatings Technology,2009,204(6-7):1056-1060.
[17]Xiang L.Zwischenschichten zur entwicklung haftfester CVD-diamantbeschichtungen auf Stahl[D].TU Braunshweig,2002.
[18]Wang T,Zhuang H,Jiang X.One step deposition of highly adhesive diamond films on cemented carbide substrates via diamond/β-SiC composite interlayers[J].Applied Surface Science,2015,359:790-796.
[19]Srikanth VVSS,Hisham SA,Staedler T,et al.Nanocrystalline diamond/β-SiC composite interlayers for the deposition of continuous diamond films on W and Mo substrate[J].Surface&Coatings Technology,2007,201(22):8981-8985.
[20]Srikanth VVSS,Jiang X,Kopf A.Deposition of diamond/β-SiC nanocomposite films onto a cutting tool material[J].Surface&Coatings Technology,2010,204(15):2362-2367.
[21]Song BH,Yoon DY.The effect of d.c.glow discharge on hot filament chemical vapor deposition of diamond[J].Diamond&Related Materils,2000,9(1):82-86.
[22]Dua AK,George VC,Friedrich M,et al.Effect of deposition parameters on different stages of diamond deposition in HFCVD technique[J].Diamond&Related Materils,2004,13(1):74-84.
[23]Faure C,Teule-Gay L,Manaud J,et al.Mechanisms of time-modulated polarized nanocrystalline diamond growth[J].Surface&Coatings Technology,2013,222(19):97-103.
[24]Nose K,Suwa T,Ikejiri K,et al.Ion acceleration in bias-enhanced nucleation of diamond at relatively high pressures[J].Diamond&Related Materials,2011,20(5-6):687-692.
[25]Peters MG,Cummings RH.Methods for coating adherent diamond films on cemented tungsten carbide substrates:US,US5236740[P].1993-08-17[2016-10-12].
[26]Morell G,Perez W,Ching-Prado E,et al.Anharmonic interactions in beryllium oxide[J].Physical Review B?1996,53(9):5388-5395.
[27]Gheeraert E,Deneuville A,Bonnot AM,et al.Defects and stress analysis of the Raman spectrum of diamond films[J].Bulletin of Toyama Technical College,1991,1(5-6):525-528.
[28]Knight DS,White WB.Characterization of diamond films by Raman spectroscopy[J].Journal of Materials Research,1989,4(2):385-393.
[29]Nistor LC,Landuyt JV,Ralchenko VG,et al.Nanocrystalline diamond films:transmission electron microscopy and Raman spectroscopy characterization[J].Diamond&Related Materials,1997,6(1):159-168.
[30]Ferrai AC,Robertson J.Origin of the 1 150 cm~(-1)Raman mode in nano cry stalline diamond[J].Physical Review B,2001,63(12):263-271.
[31]Lopezrios T,Sandre E,Leclercq S,et al.Polyacetylene in diamond films evidenced by surface enhanced Raman scattering[J].Physical Review Letters,1996,76(26):4935-4938.
[32]Nemanich RJ,Glass JT,Lucovsky G,et al.Raman scattering characterization of carbon bonding in diamond and diamondlike thin films[J].Journal of Vacuum Science&Technology A:Vacuum Surfaces&Films,1988,6(3):1783-1787.
[33]Chiang MJ,Hon MH.Positive dc bias-enhanced diamond nucleation with high CH_4 concentration[J].Diamond&Related Materials,2001,10(8):1470-1476.
[34]Wang WN,Fox NA,May PW,et al.Laser Raman studies of poly crystalline and amorphic diamond films[J].Physica Status Solidi,1996,154(1):255-268.
[35]Nistor LC,Landuyt Van J,Ralchenko VG,et al.Nanocrystalline diamond films:transmission electron microscopy and Raman spectroscopy characterization[J].Diamond&Related Materials,1997,6(1):159-168.
[36]Sasaki Y,Nishina Y,Sato M,et al.Raman study of SiC fibres made from polycarbosilane[J].Journal of Material Science,1987,22(2):443-448.
[37]Olego D,Cardona M.Raman scattering by coupled LO-phonon-plasmon modes and forbidden TOphonon Raman scattering in heavily doped p-type GaAs[J].Physical Review B,1981,24(12):7217-7232.
[38]Zhao YL,Zhang RQ,Srikanth WSS,et al.Possible gas-phase reactions of H_2/CH_4/Tetramethylsilane in diamond/β-SiC nanocomposite film deposition:an Ab-initio study[J].Journal of Physical Chemistry A,2007,111(18):3554-3559.
[39]Wei QP,Yu ZM,Ashfold MNR,et al.Fretting wear and electrochemical corrosion of well-adhered CVD diamond films deposited on steel substrates with a WC-Co interlayer[J].Diamond&Related Materials,2010,19(10):1144-1152.
[40]Donnet JB,Paulmier D,Oulanti H,et al.Diffusion of cobalt in diamond films synthesized by combustion flame method[J].Carbon,2004,42(11):2215-2221.
[41]Wei QP,Yu ZM,Ashfold MNR,et al.Synthesis of micro-or nano-crystalline diamond films on WCCo substrates with various pretreatments by hot filament chemical vapor deposition[J].Applied Surface Science,2010,256(13):4357-4364.
[42]Seng WF,Bames PA.Calculations of cobalt silicide and carbide formation on SiC using the Gibbs free energy[J].Materials Science Engineering B,2000,76(3):225-231.
[43]Zhuang H,Zhang L,Staedler T,et al.Highly selective diamond andβ-SiC crystal formation at increased atomic hydrogen concentration:a route for synthesis of high-quality and patterned hybrid diamond/β-SiC composite film[J].Scripta Materialia,2011,65(6):548-551.
[2]Haubner R,Kalss W.Diamond deposition on hardmetal substrates-comparison of substrate pre-treatments and industrial applications[J].International Journal of Refractory Metals&Hard Materials,2010,28(4):475-483.
[3]Liu MN,Bian YB,Zheng SJ,et al.Growth and mechanical properties of diamond films on cemented carbide with buffer layers[J].Thin Solid Films,2015,34:165-169.
[4]Lu P,Gomez H,Xiao X,et al.Coating thickness and interlayer effects on CVD-diamond film adhesion to cobalt-cemented tungsten carbides[J].Surface&Coatings Technology,2013,215(2):272-279.
[5]Mandal S,Thomas ELH,Jenny TA,et al.Chemical nucleation of diamond films[J].ACS Applied Materials&Interfaces,2016,8(39):26220-26225.
[6]Park BS,Baik YJ,Lee KR,et al.Behaviour of Co binder phase during diamond deposition on WC-Co substrate[J].Diamond&Related Materials,1993,2(5):910-917.
[7]Dumpala R,Kumar N,Kumaran CR,et al.Adhesion characteristic of nano-and microcrystalline diamond coatings:Raman stress mapping of the scratch tracks[J].Diamond&RelatedMaterials,2014,44(4):71-77.
[8]Cui Y,Wang W,Shen B,et al.A study of CVD diamonjd deposition on cemented carbide ballend milling tools with high cobalt content using amorphous ceramic interlayers[J].Diamond&Related Materials,2015,59:21-29.
[9]Hei H,Ma J,Li X,et al.Preparation and performance of chemical vapor deposition diamond coatings synthesized onto the cemented carbide micro-end mills with a SiC interlayer[J].Surface&Coatings Technology,2015,261:272-277.
[10]Lin CR,Kuo CT,Chan RM.Improvement in adhesion of diamond films on cemented WC substrate with Ti-Si interlayers[J].Diamond&RelatedMaterials,1998,7(11-12):1628-1632.
[11]Haubner R,Lux B.Diamond deposition on steel substrates using intermediate layers[J].International Journal of Refractory Metals&Hard Materials,2006,24(5):380-386.
[12]Li YS,Tang Y,Yang Q,et al.Al-enhanced nucleation and adhesion of diamond films on WC-Co substrates[J].International Journal of Refractory Metals&Hard Materials,2008,26(5):465-471.
[13]Manaud JP,Poulon A,Gomez S.A comparative study of CrN,ZrN,NbN and TaN layers as cobalt diffusion barriers for CVD diamond deposition on WC-Co tools[J].Surface&Coatings Technology,2007,202(2):222-231.
[14]Xu F,Xu JH,Yuen MF,et al.Adhesion improvement of diamond coatings on cemented carbide with high cobalt content using PVD interlayer[J].Diamond&Related Materils,2013,34(2):70-75.
[15]Polini R,Barletta M.On the use of CrN/Cr and CrN interlayers in hot filament chemical vapour deposition(HF-CVD)of diamond films onto WCCo substrates[J].Diamond&Related Materils,2008,17(3):325-335.
[16]Qin F,Chou YK,Dohlen D,et al.Coating thickness effects on diamond coated cutting tools[J].Surface&Coatings Technology,2009,204(6-7):1056-1060.
[17]Xiang L.Zwischenschichten zur entwicklung haftfester CVD-diamantbeschichtungen auf Stahl[D].TU Braunshweig,2002.
[18]Wang T,Zhuang H,Jiang X.One step deposition of highly adhesive diamond films on cemented carbide substrates via diamond/β-SiC composite interlayers[J].Applied Surface Science,2015,359:790-796.
[19]Srikanth VVSS,Hisham SA,Staedler T,et al.Nanocrystalline diamond/β-SiC composite interlayers for the deposition of continuous diamond films on W and Mo substrate[J].Surface&Coatings Technology,2007,201(22):8981-8985.
[20]Srikanth VVSS,Jiang X,Kopf A.Deposition of diamond/β-SiC nanocomposite films onto a cutting tool material[J].Surface&Coatings Technology,2010,204(15):2362-2367.
[21]Song BH,Yoon DY.The effect of d.c.glow discharge on hot filament chemical vapor deposition of diamond[J].Diamond&Related Materils,2000,9(1):82-86.
[22]Dua AK,George VC,Friedrich M,et al.Effect of deposition parameters on different stages of diamond deposition in HFCVD technique[J].Diamond&Related Materils,2004,13(1):74-84.
[23]Faure C,Teule-Gay L,Manaud J,et al.Mechanisms of time-modulated polarized nanocrystalline diamond growth[J].Surface&Coatings Technology,2013,222(19):97-103.
[24]Nose K,Suwa T,Ikejiri K,et al.Ion acceleration in bias-enhanced nucleation of diamond at relatively high pressures[J].Diamond&Related Materials,2011,20(5-6):687-692.
[25]Peters MG,Cummings RH.Methods for coating adherent diamond films on cemented tungsten carbide substrates:US,US5236740[P].1993-08-17[2016-10-12].
[26]Morell G,Perez W,Ching-Prado E,et al.Anharmonic interactions in beryllium oxide[J].Physical Review B?1996,53(9):5388-5395.
[27]Gheeraert E,Deneuville A,Bonnot AM,et al.Defects and stress analysis of the Raman spectrum of diamond films[J].Bulletin of Toyama Technical College,1991,1(5-6):525-528.
[28]Knight DS,White WB.Characterization of diamond films by Raman spectroscopy[J].Journal of Materials Research,1989,4(2):385-393.
[29]Nistor LC,Landuyt JV,Ralchenko VG,et al.Nanocrystalline diamond films:transmission electron microscopy and Raman spectroscopy characterization[J].Diamond&Related Materials,1997,6(1):159-168.
[30]Ferrai AC,Robertson J.Origin of the 1 150 cm~(-1)Raman mode in nano cry stalline diamond[J].Physical Review B,2001,63(12):263-271.
[31]Lopezrios T,Sandre E,Leclercq S,et al.Polyacetylene in diamond films evidenced by surface enhanced Raman scattering[J].Physical Review Letters,1996,76(26):4935-4938.
[32]Nemanich RJ,Glass JT,Lucovsky G,et al.Raman scattering characterization of carbon bonding in diamond and diamondlike thin films[J].Journal of Vacuum Science&Technology A:Vacuum Surfaces&Films,1988,6(3):1783-1787.
[33]Chiang MJ,Hon MH.Positive dc bias-enhanced diamond nucleation with high CH_4 concentration[J].Diamond&Related Materials,2001,10(8):1470-1476.
[34]Wang WN,Fox NA,May PW,et al.Laser Raman studies of poly crystalline and amorphic diamond films[J].Physica Status Solidi,1996,154(1):255-268.
[35]Nistor LC,Landuyt Van J,Ralchenko VG,et al.Nanocrystalline diamond films:transmission electron microscopy and Raman spectroscopy characterization[J].Diamond&Related Materials,1997,6(1):159-168.
[36]Sasaki Y,Nishina Y,Sato M,et al.Raman study of SiC fibres made from polycarbosilane[J].Journal of Material Science,1987,22(2):443-448.
[37]Olego D,Cardona M.Raman scattering by coupled LO-phonon-plasmon modes and forbidden TOphonon Raman scattering in heavily doped p-type GaAs[J].Physical Review B,1981,24(12):7217-7232.
[38]Zhao YL,Zhang RQ,Srikanth WSS,et al.Possible gas-phase reactions of H_2/CH_4/Tetramethylsilane in diamond/β-SiC nanocomposite film deposition:an Ab-initio study[J].Journal of Physical Chemistry A,2007,111(18):3554-3559.
[39]Wei QP,Yu ZM,Ashfold MNR,et al.Fretting wear and electrochemical corrosion of well-adhered CVD diamond films deposited on steel substrates with a WC-Co interlayer[J].Diamond&Related Materials,2010,19(10):1144-1152.
[40]Donnet JB,Paulmier D,Oulanti H,et al.Diffusion of cobalt in diamond films synthesized by combustion flame method[J].Carbon,2004,42(11):2215-2221.
[41]Wei QP,Yu ZM,Ashfold MNR,et al.Synthesis of micro-or nano-crystalline diamond films on WCCo substrates with various pretreatments by hot filament chemical vapor deposition[J].Applied Surface Science,2010,256(13):4357-4364.
[42]Seng WF,Bames PA.Calculations of cobalt silicide and carbide formation on SiC using the Gibbs free energy[J].Materials Science Engineering B,2000,76(3):225-231.
[43]Zhuang H,Zhang L,Staedler T,et al.Highly selective diamond andβ-SiC crystal formation at increased atomic hydrogen concentration:a route for synthesis of high-quality and patterned hybrid diamond/β-SiC composite film[J].Scripta Materialia,2011,65(6):548-551.