等离子喷涂FeCrBC-NiAl-TiB_(2)复合涂层制备及性能研究

Preparation and Properties of Plasma-sprayed FeCrBC-NiAl-TiB_(2)Composite Coating

目的提高风机等机械设备关键部件的耐磨损性能,延长设备的使用寿命。方法以304不锈钢为基体,利用等离子喷涂技术,制备FeCrBC涂层和FeCrBC-NiAl-TiB_(2)复合涂层。采用X射线衍射仪、金相显微镜、扫描电子显微镜、显微硬度计,分别对涂层的微观组织、物相、显微硬度进行表征。利用摩擦磨损试验机,对FeCrBC涂层和FeCrBC-NiAl-TiB_(2)复合涂层的磨损性能进行研究,并分析其磨损机理。结果FeCrBC涂层和FeCrBC-NiAl-TiB_(2)复合涂层表面均由致密光滑区域和较为疏松的半熔融颗粒等组成,涂层与基体结合得较为紧密,界面处无明显裂纹,结合强度较高,2种涂层的结合强度分别为69.5、69.1 MPa。FeCrBC涂层和FeCrBC-NiAl-TiB_(2)复合涂层的显微硬度相当,分别为823.3HV0.1、810.8HV0.1。FeCrBC-NiAl-TiB_(2)复合涂层的磨损体积为0.11 mm^(3),与FeCrBC涂层相比,复合涂层的磨损率减小了38.1%,具有良好的耐磨损性能。FeCrBC-NiAl-TiB_(2)复合涂层的磨损机理主要为磨粒磨损和疲劳磨损。结论复合涂层中TiB_(2)与FeCrBC相和NiAl相的润湿性良好,结合紧密。FeCrBC-NiAl-TiB_(2)复合涂层因其存在均匀分布的TiB_(2)、(Fe,Cr)_(2)(B,C)、(Fe,Cr)_(3)(B,C)等硬质相,显著提高了涂层的耐磨性能。FeCrBC-NiAl-TiB_(2)复合涂层可以有效提高基体的耐磨损性能,具有良好的应用前景。

Composite coatings can effectively improve the strength,fracture toughness,wear resistance,and other properties of traditional single material coatings,which becomes one of the research hotspots in recent years.Due to high hardness,low density(4.5 g/cm3),and good oxidation resistance,TiB_(2)-metal composite coating is believed to be one of the more potential candidates for improving the surface wear resistance of key components.In this paper,the microstructure,phase structure,and bonding strength of plasma-sprayed FeCrBC-NiAl-TiB_(2)composite coatings were characterized.The abrasion resistance of FeCrBC and FeCrBC-NiAl-TiB_(2)composite coatings was also studied systematically.Raw materials TiB_(2)(10wt.%),NiAl(10wt.%),and FeCrBC(80wt.%)powder were mixed in a three-dimensional mixer for 60 min in proportion to prepare the FeCrBC-NiAl-TiB_(2)composite powder.The 304 stainless steel(30 mm×10 mm×3 mm andφ25.4 mm×10 mm)was selected as the substrate.Before sandblasting,the samples were cleaned with acetone to remove the surface oil.An atmospheric plasma spraying system(BSX-80,Xiamen Baisunxing Automation Co.,LTD.)was used to deposit the FeCrBC and FeCrBC-NiAl-TiB_(2)composite coating.The phase of powder and coating was determined by an X-ray diffractometer(XRD,CuKα,D8 Advanced,Bruker).The microhardness of the coating was measured with a Vickers hardness tester(Laizhou Huayin,HVS-1000).The bonding strength of the coating was determined with an electronic universal testing machine(WJinan Liantai,DW-100Y).The morphology of the coating was observed with a scanning electron microscope(JSM-6390LA)and an energy-dispersive X-ray spectroscopy(EDX,INCA X-MAX).The wear resistance of samples was tested with a pin-disc friction and wear testing machine(Zhongke Kaihua,SFT-2M).Before the test,the surface of the samples was polished with SiC sandpaper to keep a similar roughness(Ra 0.2-0.5μm).A displacement sensor probe was applied for the morphology of the grinding of the samples.The wear rate was calculated and the morphology after the friction surface was observed.The surfaces of FeCrBC and FeCrBC-NiAl-TiB_(2)composite coatings were both composed of dense and smooth areas and loose molten particles.Because the melting point of TiB_(2)particles was higher than the metal phase,the spreading deformation after particle impact was smaller,hence the surface roughness of the composite coating increased.Both FeCrBC and FeCrBC-NiAl-TiB_(2)composite coatings were closely bonded to the substrate,and there was no obvious crack at the interface.The bonding strength of FeCrBC and FeCrBC-NiAl-TiB_(2)composite coatings was 69.5 MPa and 69.1 MPa respectively.TiB_(2)in the composite coating had good wettability with the FeCrBC phase and NiAl phase.The microhardness of FeCrBC coating and FeCrBC-NiAl-TiB_(2)composite coating were equivalent,which were 823.3HV0.1 and 810.8HV0.1 respectively.The wear volume and wear rate of the FeCrBC-NiAl-TiB_(2)composite coating were 0.11 mm3 and 0.65×10^(–5)mm^(3)/(N·m),respectively.Compared with the FeCrBC coating,the wear rate of the FeCrBC-NiAl-TiB_(2)composite coating was reduced by 38.1%,which exhibited good wear resistance.The wear mechanism of FeCrBC-NiAl-TiB_(2)composite coating was mainly abrasive wear and fatigue wear.Because of the uniform distribution of hard phases such as TiB_(2),(Fe,Cr)_(2)(B,C),and(Fe,Cr)_(3)(B,C)on the surface of the coating,the wear resistance of the FeCrBC-NiAl-TiB_(2)composite coating is significantly improved.The FeCrBCNiAl-TiB_(2)composite coating can effectively improve the wear resistance of the substrate and has a good application prospect.