料浆包渗法制备MoSi_2高温抗氧化涂层
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摘要
目的开发钼基体表面制备Mo Si2高温抗氧化涂层的新工艺。方法创造性地采用料浆包渗法在钼基体表面制备MoSi2高温抗氧化涂层,使用X射线衍射仪(XRD)结合能谱仪(EDS)分析并确定涂层的主体层和过渡层物相。通过扫描电子显微镜(SEM)观察涂层表面及断面的微观组织形貌,探讨硅化物形成机理并建立料浆包渗过程模型。探究料浆涂覆厚度、NaF活化剂含量、热处理温度、热处理时间等工艺参数对涂层厚度的影响。结果采用料浆包渗法在钼基体表面制备出了双层硅化物涂层,外层为多边棱柱状MoSi2,内层为均匀致密的玻璃状Mo5Si3。料浆涂覆厚度较薄时,涂层内层(Mo5Si3)加厚,而外层(MoSi2)变薄。活化剂NaF质量分数在0～20%内与涂层厚度呈正相关性,质量分数达到20%后,涂层厚度基本不变。热处理温度在活化剂NaF和渗剂Si粉相变转化点附近,对涂层生成起较大作用。热处理时间越长,涂层总厚度越大,但涂层生成速率与热处理时间呈倒抛物线关系。结论采用料浆包渗法,能在较低热处理温度下(800～1400℃)及较短的热处理时间内(1～7 h)在钼基体表面成功制备出致密的MoSi2高温抗氧化涂层,提高热处理温度和增加时间能够增加涂层厚度。
The work aims to develop a novel process for preparing MoSi2 high temperature oxidation resistant coating on the surface of molybdenum substrate. The Mo Si2 coating was synthesized on the surface of molybdenum substrate subtly by slurry infiltration method. The phases of the coating, including the main layer and transition layer, were analyzed and determined by X-ray diffraction(XRD) and energy dispersive spectrometer(EDS). The morphology of microstructure on surface and cross-section of the coating was observed by scanning electron microscopy(SEM). Model of slurry infiltration process was established to illustrate the formation mechanism of the silicide. The effects of process parameters, such as slurry coating thick-ness, activator(NaF) content, temperature and duration of heat treatment, on the thickness of silicide coating were investigated in detail. Bilayer silicide coating was prepared on the surface of the molybdenum substrate by slurry infiltration technology. The outer layer was a polygonal prismatic MoSi2, while the inner layer was a uniform and dense glassy Mo5Si3. Thinner slurry led to thicker inner layer(Mo5Si3) and thinner outer layer(MoSi2). The coating thickness was linearly correlated with the content of activator(NaF, 0～20wt%), and it was almost constant when the content of NaF was above 20wt%. The coating formation was effected significantly when the heat treatment temperature was around the phase transformation point of activator NaF and infiltration agent Si. The total thickness of the coating grew with longer heat treatment duration, but the coating formation rate had an inverted parabolic relationship with extended duration. The dense MoSi2 oxidation resistant coating can be synthesized on the surface of molybdenum by slurry infiltration technology at a relatively low heat treatment temperature(800～1400 ℃) in a relatively short heat treatment time(1～7 h). The total thickness of the coating can be increased by increasing heat treatment temperature and extending the heating duration.
The work aims to develop a novel process for preparing MoSi2 high temperature oxidation resistant coating on the surface of molybdenum substrate. The Mo Si2 coating was synthesized on the surface of molybdenum substrate subtly by slurry infiltration method. The phases of the coating, including the main layer and transition layer, were analyzed and determined by X-ray diffraction(XRD) and energy dispersive spectrometer(EDS). The morphology of microstructure on surface and cross-section of the coating was observed by scanning electron microscopy(SEM). Model of slurry infiltration process was established to illustrate the formation mechanism of the silicide. The effects of process parameters, such as slurry coating thick-ness, activator(NaF) content, temperature and duration of heat treatment, on the thickness of silicide coating were investigated in detail. Bilayer silicide coating was prepared on the surface of the molybdenum substrate by slurry infiltration technology. The outer layer was a polygonal prismatic MoSi2, while the inner layer was a uniform and dense glassy Mo5Si3. Thinner slurry led to thicker inner layer(Mo5Si3) and thinner outer layer(MoSi2). The coating thickness was linearly correlated with the content of activator(NaF, 0～20wt%), and it was almost constant when the content of NaF was above 20wt%. The coating formation was effected significantly when the heat treatment temperature was around the phase transformation point of activator NaF and infiltration agent Si. The total thickness of the coating grew with longer heat treatment duration, but the coating formation rate had an inverted parabolic relationship with extended duration. The dense MoSi2 oxidation resistant coating can be synthesized on the surface of molybdenum by slurry infiltration technology at a relatively low heat treatment temperature(800～1400 ℃) in a relatively short heat treatment time(1～7 h). The total thickness of the coating can be increased by increasing heat treatment temperature and extending the heating duration.
引文
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[16]曹正,田晓东,李宁,等.Nb-Ti-Si合金表面辉光离子渗Mo/包埋渗Si制备Mo Si2涂层的研究[J].表面技术,2015(1):68-71.CAO Zheng,TIAN Xiao-dong,LI Ning,et al.Preparation of Mo Si2 coating by Nb-Ti-Si alloy by glow plasma deposition of Mo/Pack cementation of Si[J].Surface technology,2015(1):68-71.
[17]ZHANG H,GU S.Preparation and oxidation behavior of Mo Si2-Cr Si2-Si3N4,composite coating on Mo substrate[J].International journal of refractory metals&hard materials,2013,41(11):128-132.
[18]ZHANG H,LV J,WU Y,et al.Oxidation behavior of(Mo,W)Si2-Si3N4 composite coating on molybdenum substrate at 1600℃[J].Ceramics international,2015,41(10):14890-14895.
[19]张厚安,吴艺辉,古思勇,等.钼表面(Mo,W)Si2-Si3N4复合涂层的低温氧化行为研究[J].厦门理工学院学报,2013,21(3):1-4.ZHANG Hou-an,WU Yi-hui,GU Si-yong,et al.Analysis of low temperature oxidation behavior of molybdenum(Mo,W)Si2-Si3N4 composite coatings[J].Journal of Xiamen University of Technology,2013,21(3):1-4.
[20]ZHANG H,HUANG Y,LIN J,et al.Growth kinetics and microstructure evolution of intermediate phases in MoSi2-Si3N4-WSi2/Mo diffusion couples[J].Journal of materials engineering&performance,2016,26(2):1-6.
[21]汤德志.钼合金表面涂层的制备及性能研究[D].长沙:中南大学,2014.TANG De-zhi.Research on the preparation and properties of coating on molybdenum[D].Changsha:Central South University,2014.
[22]黄羽.基于Si高温扩散的Mo-W-Si-N系涂层钼材的研制[D].厦门:厦门理工学院,2016.HUANG Yu.Development of Mo-W-Si-N coated molybdenum based on Si high-temperature diffusion of Si[D].Xiamen:Xiamen University of Technology,2016.
[23]HUANG C,ZHANG Y,RUI V.Microstructure and anti-oxidation behavior of laser clad Ni-20Cr coating on molybdenum surface[J].Surface&coatings technology,2010,205(3):835-840.
[24]肖来荣,易丹青,蔡志刚,等.包渗法制备硅化物涂层的结构形貌及形成机理[J].中南大学学报(自然科学版),2008,39(1):48-53.XIAO Lai-rong,YI Dan-qing,CAI Zhi-gang,et al.Microstructure and formation mechanism of silicide coating prepared by pack cementation[J].Journal of Central South University(natural science),2008,39(1):48-53.
[25]MASSALSKI T B.Binary alloy phase diagrams[M].Materials Park(OH):ASM International,1990.
[26]肖来荣,蔡志刚,宋成.Mo(Si,Al)2高温抗氧化涂层的形貌与结构研究[J].兵器材料科学与工程,2006,29(3):54-57.XIAO Lai-rong,CAI Zhi-gang,SONG Cheng.Morphology and structure of Mo(Si,Al)2 high temperature oxidation resistant coating[J].Ordnance material science and engineering,2006,29(3):54-57.
[27]徐克玷.钼的材料科学与工程[M].北京:冶金工业出版社,2014.XU Ke-zhen.Material science and engineering of molybdenum[M].Beijing:Metallurgical Industry Press,2014.
[28]CALLISTER W D J,RETHWISCH D G.材料科学与工程基础[M].第四版.郭福,马立民,等译.北京:化学工业出版社,2015:259-264.CALLISTER W D J,RETHWISCH D G.Fundamentals of materials science and engineering[M].4th edition.GUO Fu,MA Li-min,et al,translated.Beijing:Chemical Industry Press,2015:259-264.
[2]何斌衡.稀土钼合金的制备及工艺与性能的研究[D].长沙:中南大学,2012.HE Bin-heng.Study on preparation technology and properties of RE molybdenum alloys[D].Changsha:Central South University,2012.
[3]LIU G,ZHANG G J,JIANG F,et al.Nano structured high-strength molybdenum alloys with unprecedented tensile ductility[J].Nature materials,2013,12(4):344-351.
[4]于志涛,王快社,胡平,等.低氧TZM合金研究进展[J].材料导报,2015,29(1):92-98.YU Zhi-tao,WANG Kuai-she,HU Ping,et al.Progress of low oxygen TZM molybdenum alloy[J].Materials review,2015,29(1):92-98.
[5]YANG F,WANG K S,HU P,et al.La doping effect on TZM alloy oxidation behavior[J].Journal of alloys&compounds,2014,593(5):196-201.
[6]安耿.钼及钼合金表面Mo Si2抗氧化涂层的研究进展[J].中国钼业,2013,37(2):55-60.AN Geng.Research progress on the MoSi2 oxidation resistance coating of molybdenum and its alloys[J].China molybdenum,2013,37(2):55-60.
[7]宋瑞,王快社,胡平,等.钼及钼合金表面高温抗氧化涂层研究现状[J].材料导报,2016,30(5):69-74.SONG Rui,WANG Kuai-she,HU Ping,et al.Present situation of anti-oxidation coatings preparation on molybdenum and its alloys[J].Materials review,2016,30(5):69-74.
[8]霍达,李文生,冯力,等.喷涂工艺对MoSi2-Al2O3涂层组织与性能的影响[J].表面技术,2018(4):267-273.HUO Da,LI Wen-sheng,FENG Li,et al.Effect of spraying process on microstructure and properties of MoSi2-Al2O3 coatings[J].Surface technology,2018(4):267-273.
[9]张稳稳,林涛,邵慧萍.料浆法制备Mo表面硅化物涂层的研究[J].粉末冶金技术,2013,31(1):18-21.ZHANG Wen-wen,LIN Tao,SHAO Hui-ping.Study on the silicide coatings on molybdenum by slurry method[J].Powder metallurgy technology,2013,31(1):18-21.
[10]YOON J K,KIM G H,BYUN J Y,et al.Formation of Mo Si2-Si3N4 composite coating by reactive diffusion of Si on Mo substrate pretreated by ammonia nitridation[J].Scripta materialia,2002,47(4):249-253.
[11]WANG Y,WANG D,YAN J.Preparation and characterization of MoSi2/MoB composite coating on Mo substrate[J].Journal of alloys&compounds,2014,589(9):384-388.
[12]LIU J,GONG Q,SHAO Y,et al.In-situ fabrication of Mo Si2/Si C-Mo2C gradient anti-oxidation coating on Mo substrate and the crucial effect of Mo2C barrier layer at high temperature[J].Applied surface science,2014,308:261-268.
[13]JIANG Y,GONG Q,CAI Z,et al.Fabrication of Cr Si2/Mo Si2/Si C-Mo2C gradient composite coating on Mo substrate and the stabilizing effect of Cr on the coating's anti-oxidation properties[J].Surface&coatings technology,2015,282:188-199.
[14]李鹏飞,范景莲,成会朝,等.钼合金表面Mo Si2涂层的制备工艺和形成机理[J].中南大学学报(自然科学版),2012,43(7):2506-2512.LI Peng-fei,FAN Jing-lian,CHENG Hui-chao,et al.Preparation and formation mechanism of MoSi2 coating on molybdenum alloy[J].Journal of Central South University(natural science),2012,43(7):2506-2512.
[15]李涌泉,杜晓娟,蒋亮,等.活性元素Y对高Nb-Ti Al合金表面硅化物渗层组织的影响[J].表面技术,2016,45(10):28-33.LI Yong-quan,DU Xiao-juan,JIANG Liang,et al.Effect of active element Y on formation of silicide co-deposition coatings on high Nb-TiAl alloy[J].Surface technology,2016,45(10):28-33.
[16]曹正,田晓东,李宁,等.Nb-Ti-Si合金表面辉光离子渗Mo/包埋渗Si制备Mo Si2涂层的研究[J].表面技术,2015(1):68-71.CAO Zheng,TIAN Xiao-dong,LI Ning,et al.Preparation of Mo Si2 coating by Nb-Ti-Si alloy by glow plasma deposition of Mo/Pack cementation of Si[J].Surface technology,2015(1):68-71.
[17]ZHANG H,GU S.Preparation and oxidation behavior of Mo Si2-Cr Si2-Si3N4,composite coating on Mo substrate[J].International journal of refractory metals&hard materials,2013,41(11):128-132.
[18]ZHANG H,LV J,WU Y,et al.Oxidation behavior of(Mo,W)Si2-Si3N4 composite coating on molybdenum substrate at 1600℃[J].Ceramics international,2015,41(10):14890-14895.
[19]张厚安,吴艺辉,古思勇,等.钼表面(Mo,W)Si2-Si3N4复合涂层的低温氧化行为研究[J].厦门理工学院学报,2013,21(3):1-4.ZHANG Hou-an,WU Yi-hui,GU Si-yong,et al.Analysis of low temperature oxidation behavior of molybdenum(Mo,W)Si2-Si3N4 composite coatings[J].Journal of Xiamen University of Technology,2013,21(3):1-4.
[20]ZHANG H,HUANG Y,LIN J,et al.Growth kinetics and microstructure evolution of intermediate phases in MoSi2-Si3N4-WSi2/Mo diffusion couples[J].Journal of materials engineering&performance,2016,26(2):1-6.
[21]汤德志.钼合金表面涂层的制备及性能研究[D].长沙:中南大学,2014.TANG De-zhi.Research on the preparation and properties of coating on molybdenum[D].Changsha:Central South University,2014.
[22]黄羽.基于Si高温扩散的Mo-W-Si-N系涂层钼材的研制[D].厦门:厦门理工学院,2016.HUANG Yu.Development of Mo-W-Si-N coated molybdenum based on Si high-temperature diffusion of Si[D].Xiamen:Xiamen University of Technology,2016.
[23]HUANG C,ZHANG Y,RUI V.Microstructure and anti-oxidation behavior of laser clad Ni-20Cr coating on molybdenum surface[J].Surface&coatings technology,2010,205(3):835-840.
[24]肖来荣,易丹青,蔡志刚,等.包渗法制备硅化物涂层的结构形貌及形成机理[J].中南大学学报(自然科学版),2008,39(1):48-53.XIAO Lai-rong,YI Dan-qing,CAI Zhi-gang,et al.Microstructure and formation mechanism of silicide coating prepared by pack cementation[J].Journal of Central South University(natural science),2008,39(1):48-53.
[25]MASSALSKI T B.Binary alloy phase diagrams[M].Materials Park(OH):ASM International,1990.
[26]肖来荣,蔡志刚,宋成.Mo(Si,Al)2高温抗氧化涂层的形貌与结构研究[J].兵器材料科学与工程,2006,29(3):54-57.XIAO Lai-rong,CAI Zhi-gang,SONG Cheng.Morphology and structure of Mo(Si,Al)2 high temperature oxidation resistant coating[J].Ordnance material science and engineering,2006,29(3):54-57.
[27]徐克玷.钼的材料科学与工程[M].北京:冶金工业出版社,2014.XU Ke-zhen.Material science and engineering of molybdenum[M].Beijing:Metallurgical Industry Press,2014.
[28]CALLISTER W D J,RETHWISCH D G.材料科学与工程基础[M].第四版.郭福,马立民,等译.北京:化学工业出版社,2015:259-264.CALLISTER W D J,RETHWISCH D G.Fundamentals of materials science and engineering[M].4th edition.GUO Fu,MA Li-min,et al,translated.Beijing:Chemical Industry Press,2015:259-264.