等离子喷涂WC-10Co-4Cr涂层的组织演变与抗腐蚀磨损性能

为提高不锈钢表面的抗腐蚀耐磨损性能,利用等离子喷涂的方法制备了2种晶粒尺寸的WC-10Co-4Cr涂层,采用SEM及EDS、XRD表征了涂层的组织和物相结构,进行了不同温度下的摩擦磨损试验,研究分析了晶粒尺寸对涂层组织与摩擦性能的影响。研究表明:WC-10Co-4Cr涂层微观结构中包含WC、W2C、W6Co6C,还存在Co/Cr(W,C)、W2(C,O)相;微米涂层中存在析出的W2C沿WC颗粒表面外延生长的包覆结构,而纳米WC涂层中,团聚粒子沿扁平粒子边界收缩,减少了扁平粒子内部的垂直贯穿裂纹。在室温和200℃时,纳米WC-10Co-4Cr涂层的摩擦系数与平均磨损率均优于微米涂层。纳米WC-10Co-4Cr涂层在室温磨损的机制为硬质颗粒诱发的犁削磨损,在200℃时为以粘着磨损为主与微域犁削相结合的磨损形式。在3.5%NaCl溶液中的电化学特性显示,WC-10Co-4Cr涂层将1Cr18Ni9Ti基体的腐蚀电位由–612m V提高到–317～–252 mV,腐蚀倾向得以减弱。     

WC颗粒对WC-10Co-4Cr涂层结构演变与性能的影响

为提高不锈钢表面的抗腐蚀耐磨损性能,利用等离子喷涂的方法制备了两种晶粒尺寸的WC-10Co-4Cr涂层,采用SEM、XRD表征了涂层的物相结构,在不同温度下进行了摩擦磨损试验,研究分析了晶粒对涂层微观结构与摩擦性能的影响。研究表明：相比较,纳米WC-10Co-4Cr涂层微观结构中包含WC、W₂C,还存在Co/Cr(W, C)的γ相,未发现微米涂层中析出的W2C将沿WC颗粒表面外延生长的包覆结构,而且纳米团聚粒子更容易沿扁平粒子边界收缩,明显减少了粒子内部的垂直贯穿裂纹。在室温和200℃时,纳米WC-10Co-4Cr涂层摩擦系数与平均磨损率均优于微米涂层。与微米涂层相比较,纳米WC-10Co-4Cr涂层在室温磨损的根源在于硬质颗粒诱发的犁削磨损,在200℃时为以粘着磨损为主的微域犁削相结合的磨损模式。并在3.5%NaCl溶液中将1Cr18Ni9Ti基体的腐蚀电位由-617mV提高到-335~-290mV,降低了腐蚀倾向。     

超音速火焰喷涂微纳米WC-CoCr涂层的性能与空蚀行为

采用超音速火焰喷涂(HVOF)制备普通微米和微纳米WC-10Co4Cr金属陶瓷涂层,使用光学显微镜、扫描电镜和X射线衍射仪方法分析涂层的组织结构;测量涂层的显微硬度、孔隙率及开裂韧性;采用超声振动空蚀装置在淡水介质中研究WC-10Co4Cr涂层的抗空蚀性能和空蚀行为,并探讨涂层的空蚀机理。结果表明:采用HVOF制备的微纳米WC-10Co4Cr涂层主要由WC相、非晶Co Cr相和微量的W2C相组成,涂层中WC未产生明显的脱碳现象;HVOF工艺制备的微纳米WC-10Co4Cr涂层的力学性能和抗空蚀性能明显优于普通WC-10Co4Cr涂层的,在稳定空蚀阶段淡水中微纳米涂层的抗空蚀性能比普通涂层的提高大约1倍。     

等离子喷涂WC-12Co/NiCrAl复合涂层的摩擦磨损特性

以NiCrAl涂层为粘结层,用等离子喷涂工艺在TC4钛合金表面制备了WC-12Co/NiCrAl复合涂层。通过扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪(XRD)和显微硬度仪等手段分析了涂层微观形貌、化学成分和显微硬度,并用磨损试验考察了WC-12Co/NiCrAl复合涂层的摩擦磨损特性。结果表明:WC-12Co涂层表面未熔颗粒较多,涂层截面孔隙率为10.2%;WC发生部分分解,出现W2C、Co6W6C等新相;涂层与基体结合界面为机械结合+局部微冶金结合方式;显微硬度为双态Weibull分布,呈现不同位置结构的差异化。WC-12Co涂层表现出良好的减摩及耐磨性能,同载荷下摩擦因数低于基体,磨损失重为基体的1/10,磨粒磨损是其主要磨损机制。     

高焓等离子喷涂WC-10Co4Cr涂层的耐磨性

为提高马氏体不锈钢（0Cr13Ni4Mo）的表面硬度及耐磨性能,对不锈钢表面进行高焓等离子喷涂WC10Co4Cr强化,对涂层进行组织观察和物相组成分析,并在不同温度下进行了摩擦磨损试验。研究表明：WC10Co4Cr涂层组织致密,主要由WC物相构成,另外还有少量的W2C和Co25Cr25W8C2。在室温和高温（400 ℃）时,WC10Co4Cr涂层均具有较低的摩擦因数。室温时,基体的磨损机制主要以粘着磨损和磨粒磨损为主。WC10Co4Cr涂层其磨损机制主要以微切削为主。400 ℃条件下,不锈钢基体的磨损机理主要以粘着磨损和剥层为主,磨痕边缘部位主要以磨粒磨损为主。WC10Co4Cr涂层试样的磨损机制主要以磨粒磨损为主,伴随有剥层现象出现。     

表面喷涂对不锈钢零件耐磨性能的影响

在不锈钢表面采用超音速火焰喷涂了WC-10Co-4Cr涂层,并对喷涂粉末和涂层的显微形貌、物相组成进行了表征,研究了基体与涂层的耐磨性能。结果表明,不锈钢表面涂层与基体以机械结合为主、冶金结合为辅,基体与涂层间过渡良好,未发现气孔或者微裂纹缺陷;原始喷涂粉末的物相组成为WC、Co和少量Co3W3C相,经过超音速火焰喷涂处理后,涂层的物相组成为WC、Co6W6C和W2C相;经过超音速火焰喷涂处理后,涂层的摩擦磨损性能明显优于不锈钢基体,这主要与致密的涂层硬度较高、抗摩擦磨损能力更强有关。     

等离子喷涂沉积WC-10Co4Cr涂层的脱碳机制与腐蚀摩擦学特性

为提高不锈钢摩擦副在腐蚀环境中的服役寿命,利用等离子喷涂技术制备了WC-10Co4Cr涂层,研究了涂层的物相结构、腐蚀摩擦学特性与电化学特性。研究表明,等离子喷涂WC-10Co4Cr涂层中的WC脱碳产生少量W_2C、W以及η相,当喷涂电流为650A,电压为56V时,涂层孔隙率低、致密性好。涂层在中性溶液中的摩擦系数为0.3387~0.3682,呈现伴随(WC、W_2C)-CoCr电偶腐蚀的磨料磨损;在酸性溶液中摩擦系数为0.3224~0.3981,表现为CoCr相的点蚀磨损。等离子喷涂的WC-10Co4Cr涂层增强了1Cr18Ni9Ti基体的耐腐蚀能力,基体在3.5%NaCl溶液中腐蚀电位由-617mV提高到-335~-290mV;在酸溶液中将基体的腐蚀电位由-502mV提高到-206~-179mV。     

超音速火焰喷涂微、纳米结构WC-10Co4Cr涂层及其性能

采用超音速火焰喷涂技术（HVOF）在06Cr13Ni4Mo不锈钢基体上分别制备了微米结构、纳米结构WC-10Co4Cr涂层。通过X射线衍射仪（XRD）和扫描电子显微镜（SEM）表征和分析了不同结构WC-10Co4Cr涂层的物相组成、微观组织结构,并对涂层的显微硬度、孔隙率、结合强度、抗冲蚀性能进行了对比,探讨了涂层泥沙冲蚀机理。结果表明：HVOF制备的纳米结构 WC-10Co4Cr涂层组织致密,孔隙率更低,涂层的显微硬度、结合强度高于微米涂层,冲蚀质量损失量也小于微米涂层;纳米结构细化了涂层晶粒,增强了涂层的显微硬度和韧性,提高了涂层的抗微切削和抗疲劳剥落性能,有利于涂层的抗泥沙冲蚀性能。     

含MoS2的超音速喷涂WC-10Co-4Cr复合涂层摩擦性能研究

利用超音速火焰喷涂方法,以WC-10Co-4Cr为基体,添加MoS2以制备WC- 10Co-4Cr/MoS2自润滑复合涂层;对比分析了添加不同含量MoS2涂层的微观组织结构和物相;重点进行了摩擦磨损试验,研究润滑相MoS2对超音速喷涂WC涂层摩擦学特性的影响机理.研究结果表明:引入的MoS2一少部分转化成新态,其余则进入WC涂层空隙中,在摩擦过程中形成润滑膜起到润滑作用,并有效地降低了摩擦因数,使摩擦磨损过程中温升降低,有效减少热损伤,提高了涂层的耐磨性能;WC-10Co-4Cr/MoS2复合涂层具有很好的自润滑性,w(MoS2)15％时WC-10Co-4Cr/MoS2复合涂层的摩擦磨损性能最佳.     

机床液压设备表面喷涂WC-10Co4Cr涂层与性能研究

采用超音速火焰喷涂法在机床液压设备表面热喷涂了WC-10Co4Cr涂层,并对涂层显微形貌、物相组成、耐磨性能和耐腐蚀性能进行了测试。结果表明,WC-10Co4Cr涂层的物相组成主要为WC、W_2C、Co Cr和Co相;WC-10Co4Cr涂层较为致密、均匀,孔隙率约为0.75%;WC-10Co4Cr涂层的体积损失量约为基体的1/150,表现出优良的抵抗滑动摩擦磨损能力;虽然电镀硬铬可以提升材料的耐腐蚀性能,但WC-10Co4Cr涂层的耐腐蚀性能更加优越,腐蚀速率约为基体材料的2%。     

WC-(W,Cr)_2C-Ni/Ag复合涂层的制备及摩擦学性能

针对众多运动部件存在严重的摩擦磨损问题,使用大气等离子喷涂(APS)设备在1Cr18Ni9Ti不锈钢金属基材上喷涂制备WC-(W,Cr)2C-Ni和WC-(W,Cr)2C-Ni/Ag两种防护涂层,使用CSM摩擦磨损试验机考察两种涂层在室温下与Si3N4球配副时的滑动摩擦磨损性能。结果表明:Ag相的添加可明显降低涂层在干摩擦条件下的摩擦因数,并能减轻涂层的磨损程度;APS制备的WC-(W,Cr)2C-Ni/Ag复合涂层不仅具有优良的自润滑性能,而且具有极佳的耐磨性能,有望作为一种新型耐磨自润滑涂层材料。     

Microstructure and Wear Resistance Evolution of HVOFSprayed WC-（W,Cr）2C-Ni Coating with Post Heat Treatment In Air Atmosphere

WC-(W,Cr)2C-Ni coating was prepared on 1Cr18Ni9Ti stainless steel and C-276 Ni-base Hastelloy by high velocity oxy-fuel(HVOF)spraying.The effect of post heat treatment in air atmosphere on the microstructure,phase composition,microhardness,fracture toughness,and wear resistance of HVOF-sprayed WC-(W,Cr)2C-Ni coating was investigated.The microstructure and phase composition of the coatings were analyzed by means of field emission scanning electron microscopy(FESEM)and X-ray diffraction(XRD).The microhardness and fracture toughness of the coatings were measured using a microhardness tester and a Vickers hardness tester.Moreover,dry friction and wear behavior of the coatings sliding against Si3N4 ball was investigated using an oscillating friction and wear tester;and the worn surfaces of the coatings were analyzed by means of scanning electron microscopy(SEM).It was found that heat treatment within 500-800°C resulted in crystallization of amorphous phase in as-sprayed coating,generating nanoscale new phases such as NiWO4,CrWO4 and Cr2WO6.Besides,heat treatment led to increase of the microhardness of as-sprayed coating,and the highest microhardness was obtained after heat treatment at 800°C.The fracture toughness and wear resistance of the as-sprayed coating increased with increasing heat treatment temperature up to 700°C but tended to decrease with further elevating temperature.In other words,the mechanical properties and wear resistance of the as-sprayed coatings were worsened owing to excessive growth of oxidation grains and depletion of ductile Ni binder after heat treatment above 700°C.Thus it was suggested that as-sprayed ceramic composite coating should be post heat treated in air at a moderate temperature of 700°C so as to achieve the optimized mechanical properties and wear resistance.     

The Dry Sliding Wear Behavior of HVOF-Sprayed WC: Metal Composite Coatings

WC-based cermet coatings containing various metallic binders such as Ni, Co, and Cr are known for their superior tribological properties, particularly abrasion resistance and enhanced surface hardness. Consequently, these systems are considered as replacements for traditional hard chrome coatings in critical aircraft components such as landing gear. The purpose of this investigation was to conduct a comparative study on the dry sliding wear behavior of three WC-based cermet coatings (WC-12Ni, WC-20Cr₂C₃-7Ni, and WC-10Co-4Cr), when deposited on carbon steel substrates. Ball on disk wear tests were performed on the coatings using a CSEM Tribometer (pin-on-disk) with a 6-mm ruby ball at 20 N applied load, 0.2 m/s sliding velocity, and sliding distances up to 2000 m. Analysis of both the coating wear track and worn ruby ball was performed using optical microscopy and an Alphastep-250 profilometer. The results of the study revealed both wear of the ruby ball and coated disks allowed for a comparison of both the ball wear and coating wear for the systems considered. Generally, the use of Co and Cr as a binder significantly improved the sliding wear resistance of the coating compared to Ni and/or Cr₂C₃.     

等离子熔覆Fe基/WC-10Co-4Cr涂层的组织与性能研究

目的 制备高强度和高硬度的耐磨性涂层,用于已磨损的机械零件表面,以延长其使用寿命,避免机器因磨损而带来的各种故障。方法 采用等离子熔覆技术在40CrMnMo表面制备WC-10Co-4Cr/Fe300合金复合熔覆层,研究不同质量分数WC-10Co-4Cr对熔覆层组织和性能的影响。利用金相显微镜、超景深光学显微镜、SEM、EDS、XRD对熔覆层的组织形貌进行表征和物相分析,借助数显显微硬度计和销盘式摩擦磨损试验机测试熔覆层的硬度和耐磨性。结果 WC-10Co-4Cr/Fe300合金作为一种复合材料,与基材形成了冶金结合,结合区域无孔洞和裂纹。熔覆层微观结构随着WC-10Co-4Cr含量的增加,逐渐由柱状晶向树枝晶过渡,它主要由Fe₆W₆C、(Cr、Fe)₂₃C₆和WC相组成。熔覆层的平均硬度大致随着WC-10Co-4Cr含量的增加而提高,当WC-10Co-4Cr的质量分数达到20%时,熔覆层的硬度最高(518.5HV0.2),大约是基体硬度的1.7倍。熔覆层的主要摩擦机理为磨粒磨损,随着WC-10Co-...     

Effect of Atmospheric Plasma Spraying Power on Microstructure and Properties of WC-(W,Cr)2C-Ni Coatings

WC-(W,Cr)₂C-Ni coatings were prepared by atmospheric plasma spraying (APS) with different spraying powers. The effect of spraying power on microstructure, phase composition, hardness, fracture toughness, and oscillating dry friction and wear behaviors of the coatings were studied. Simultaneously, the microstructure and properties of the as-sprayed coatings were compared with those of WC-17Co coating prepared under the optimal spraying power. It was found that spraying power had significant effect on the molten degree of feedstock powder and phase composition as well as microstructure and properties of WC-(W,Cr)₂C-Ni coatings. WC-(W,Cr)₂C-Ni coating deposited at a moderate spraying power of 22.5?kW had the highest fracture toughness and the best wear resistance. WC-17Co coating obtained under the moderate spraying power had poor fracture toughness and wear resistance. Moreover, the four kinds of coatings were all dominated by subsurface cracking and removal of materials when sliding against Si₃N₄ ball under unlubricated conditions.     

Microstructure and high-temperature friction and wear behavior of WC-(W,Cr)2C-Ni coating prepared by high velocity oxy-fuel spraying

WC-(W,Cr)₂C-Ni coating was prepared by high velocity oxy-fuel spraying (HVOF). The microstructure and phase composition of the as-sprayed coating and that after oxidation at high temperature were analyzed by means of scanning electron microscopy (SEM), field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), and transmission electron microscopy (TEM). The oxidation behavior of as-sprayed coating and starting powders was evaluated by thermogravimetry. Dry sliding friction and wear behavior of the WC-(W,Cr)₂C-Ni coating sliding against Si₃N₄ ball at different temperatures (room temperature 20 °C and elevated temperature of 700 °C and 800 °C) was evaluated using an oscillating friction and wear tester. Besides, the microhardness and fracture toughness of the coating was also measured. Results show that sintering agglomerated WC-20 wt.%Cr-7 wt.%Ni powder is an effective method to prepare agglomerated and sintered WC-(W,Cr)₂C-Ni composite powder. The excellent oxidation resistance of WC-(W,Cr)₂C-Ni coating is mainly resulted from a double-decker shell-core microstructure formed in the coating. The composition of the outer shell is (W,Cr)₂C phase and that of the inner shell is Cr₃C₂. During high-temperature friction and wear test, well remained hard WC phase in the WC-(W,Cr)₂C-Ni coating can guarantee its good mechanical properties and wear resistance, and newly generated nano NiWO₄, CrWO₄ and Cr₂WO₆ particles can further improve these properties significantly.     

超细/纳米结构WC-10Co-4Cr涂层的透射电镜表征与性能分析

利用真空原位还原碳化反应合成超细/纳米WC-Co复合粉末,通过添加一定量Cr获得WC-10Co-4Cr复合粉末,经团聚造粒获得喷涂用复合粉末喂料,采用超音速火焰(HVOF)喷涂系统制备出超细/纳米结构的WC-10Co-4Cr涂层。利用X射线衍射仪,扫描电子显微镜和透射电子显微镜对涂层的物相、显微组织结构、元素分布特征等进行了系统表征,并对涂层耐磨性、耐蚀性进行了测试分析。结果表明:基于原位反应合成WC-Co复合粉制备的超细/纳米结构WC-10Co-4Cr涂层具有较好的耐磨性和耐腐蚀性。涂层以WC为主相,含有非晶结构的粘结相Co(Cr),同时存在少量六方晶体结构的W_2C相和非晶复相W_2C+Co(Cr)。对涂层中元素Co和Cr的分布进行了量化分析,得到其从WC晶粒到相界到共晶区再到Co区的变化规律。结合WC-10Co-4Cr复合粉末和超音速火焰喷涂工艺的特点,阐释了Cr在WC-10Co-4Cr涂层分布状态的形成原因,并讨论了对涂层性能的影响。     

超音速火焰喷涂涂层的摩擦磨损性能研究

采用划痕分析和干砂粒/橡胶轮磨损测试,主要研究了超音速火焰喷涂(High-Velocity-Air-Fuel,简称HVAF )WC涂层与Al-Ni-Cu合金的摩擦磨损性能,并且与电镀硬铬的性能进行了对比.结果表明,HVAF WC涂层和Al-Ni-Cu合金都发生微量磨损,而电镀铬层中发生明显的增重,同时导致Al-Ni-Cu合金大量磨损.在与Al-Ni-Cu合金对磨中,HVAF WC涂层的磨损机理为磨粒磨损,而电镀硬铬为粘着磨损.滚动接触疲劳磨损对涂层均有作用.     

HVOF喷涂WC-10Co4Cr涂层的性能及滑动磨损机理

目的研究WC-10Co4Cr涂层的耐滑动磨损性能及机理。方法在0Cr13Ni5Mo不锈钢基体上,采用超音速火焰喷涂(HVOF)制备了WC-10Co4Cr金属陶瓷涂层。分析了WC-10Co4Cr涂层的物相组成、显微组织,并测试了其硬度、结合强度、孔隙率及在560 r/min和1120 r/min转速下的滑动磨损性能。结果涂层的显微硬度为1325HV0.2,结合强度为72 MPa。涂层组织致密,孔隙率为0.76%。在560 r/min下磨损10h,涂层与基体的磨损失重比为1:138.36;在1120 r/min下磨损10 h,涂层与基体的磨损失重比为1:127.44。结论在滑动摩擦磨损的初期,涂层的磨损失效机制主要表现为磨粒磨损。随着滑动速度的增大,涂层的磨损失效机制主要表现为疲劳磨损。     

亚微米WC添加对超音速火焰喷涂WC–Co涂层磨损性能影响

采用湿法球磨将亚微米WC（~300 nm）和WC–12Co粉末混合均匀并使亚微米WC均匀粘附于WC–12Co粉末的表面,采用超音速火焰喷涂方法（HVOF）在304不锈钢基体表面制备WC和WC–12Co的WC–Co复合涂层,研究亚微米WC的添加对涂层相组成、显微硬度、耐磨性能和表面形貌的影响。利用X射线衍射分析涂层相组成,压痕法测试涂层的显微硬度,通过往复式摩擦磨损实验测试磨损性能,扫描电子显微镜（SEM）对涂层磨损表面和断面进行微观形貌观察,并分析涂层的磨损过程和机制。结果表明,添加质量分数5%的亚微米WC颗粒显著提高了涂层的显微硬度（16.3%）;增强了涂层的耐磨性,磨损率从6.09×10-7 mm3/Nm减小到5.15×10-7 mm3/Nm（减小13.8%）;亚微米WC颗粒喷涂后在涂层中保持了WC相,并主要存在于WC–Co扁平粒子界面和孔隙。基于涂层中扁平粒子的结合特性与磨损失效特征,建立强化模型,分析亚微米WC颗粒对涂层扁平粒子界面的强化机制。