微米尺度与纳米尺度陶瓷颗粒等离子喷涂(APS)、超音速火焰喷涂(HVOF)、冷喷涂制备MCrAlY-Al_2O_3复合涂层的微结构与性能对比

陶瓷颗粒增强型金属基复合涂层在诸多工业领域都有需求,其中包括炼钢工业。本文中,MCr Al Y-Al2O3复合粉末通过球磨法制备,并且通过等离子喷涂、超音速火焰喷涂和冷喷涂分别制备了MCr Al Y-Al2O3复合涂层。实验结果显示,可以选用不优先使基体与Al2O3结合的复合粉末控制涂层中的Al2O3含量。涂层粉末的微结构在冷喷涂涂层和超音速火焰喷涂涂层中得到了良好的保留,这是因为喷涂粒子未熔化或部分熔化。然而,对于等离子喷涂的涂层,大多数Al2O3颗粒被隔离在层状界面,在条状界面上形成连续的氧化皮。经退火处理后,由元素扩散引起的条状界面的强化使得超音速火焰喷涂和大气等离子喷涂的涂层硬度增大。此外,冷喷涂涂层由于退火后加工硬化效果的消除,硬度增加不像超音速火焰喷涂和等离子喷涂涂层那样明显。     

热喷涂Fe基非晶合金涂层的微观结构与摩擦磨损行为

分别采用超音速火焰喷涂工艺和爆炸喷涂工艺,在Q235不锈钢基体上制备Fe基非晶合金涂层,对比研究这2种非晶合金涂层在室温下的干摩擦磨损特性,并探讨摩擦磨损机理.结果表明,与超音速火焰喷涂工艺制备的Fe基非晶合金涂层相比,采用爆炸喷涂工艺制备的涂层更致密,孔隙率为2.1％,显微硬度更高,平均硬度高达1 095.6 HV,且耐磨性更好;并且涂层摩擦因数增至稳定值的时间较短,具有更稳定的摩擦磨损行为.超音速火焰喷涂涂层的磨损形式主要以疲劳磨损为主,而爆炸喷涂涂层的磨损形式为粘着磨损和磨粒磨损的综合作用,并以粘着磨损为主.     

高效能超音速等离子喷涂制备NiCr-Cr3C2涂层特点

采用高效能超音速等离子喷涂系统(HEPJet)制备了Ni Cr-Cr3C2涂层,并对涂层性能进行了测试。结果表明采用高效能超音速等离子喷涂方法制备的Ni Cr-Cr3C2涂层结构致密,孔隙率约为1%左右,显微硬度约为986HV0.3,涂层具有明显的双相结构。EDS分析结果认为,涂层由Ni Cr和Cr3C2相交替组成。Ni Cr-Cr3C2涂层的结合强度达到68MPa,与超音速火焰(HVOF)喷涂制备的Ni Cr-Cr3C2涂层结合强度相近。超音速等离子喷涂Ni Cr-Cr3C2涂层的沉积效率测定结果约为63.8%。     

纳米涂层的制备方法

论述了几种喷涂方法制备纳米涂层,包括热喷涂方法和冷喷涂方法.热喷涂方法中介绍了等离子喷涂、超音速火焰喷涂以及爆炸喷涂制备纳米涂层的技术.     

制备工艺方法对 NiCrFeMo 涂层组织和性能影响研究

采用等离子喷涂、 超音速火焰喷涂和冷喷涂工艺制备了 NiCrFeMo 涂层, 并对涂层的金相性能、 不同基体 材料下涂层的结合性能、 不同温度下涂层的耐磨性能进行了检测。 实验结果表明： 采用冷喷涂工艺制备的涂层孔 隙率最低, 对应涂层的结合强度最高, 但冷喷涂工艺制备的涂层对基体材料较为敏感, 而超音速火焰喷涂和等离 子喷涂受基体材料影响不大。 在室温下, 冷喷涂涂层显示出较优的耐磨性能, 在高温下超音速火焰喷涂涂层显示 出较优的耐磨性能。     

热喷涂Fe基非晶合金涂层的研究现状

综述了超音速火焰喷涂(HVOF),等离子喷涂(PS)技术的性能特征,以及运用热喷涂技术制备Fe基非晶涂层的发展历史与现状。从非晶合金涂层的高硬度、耐磨性及腐蚀性能等方面阐述了非晶合金涂层的优越性,对新型Fe基非晶涂层的形成机理进行研究,探讨采用超音速火焰喷涂技术制备高质量非晶合金涂层的关键因素。并展望了采用热喷涂技术制备非晶合金涂层的未来发展趋势。     

不同热喷涂技术对铁基非晶涂层的电化学腐蚀性能的影响

文章分别采用等离子喷涂、超音速火焰喷涂、爆炸喷涂制备了铁基非晶涂层。研究了不同喷涂技术制备铁基非晶涂层的显微结构和电化学腐蚀性能,探讨了喷涂技术类型对电化学腐蚀机理的影响。结果显示,三种热喷涂技术制备铁基非晶涂层的非晶含量分别为78.23%、85.41%、89.58%。其中,爆炸喷涂制备的铁基非晶涂层拥有最优的抗腐蚀性能。不同喷涂技术所制备的涂层孔隙率和非晶含量存在较大差异,进而影响了电化学腐蚀机理和抗腐蚀性能。     

超音速火焰喷涂技术的发展与特点

介绍了超音速火焰喷涂技术的发展过程、喷枪结构及工作原理、涂层的应用、与其它喷涂方法的比较以及未来的发展方向。此外，还对超音速火焰喷涂涂层的性能(如硬度、密度、结合强度、残余应力)进行了简介。     

等离子与火焰喷涂镍铝涂层性能研究

采用等离子和火焰两种方法制备NiAl涂层,对比了NiAl复合粉末在这两种喷涂工艺条件下所得涂层的硬度、结合强度和组织结构。实验结果表明采用等离子法制备的NiAl涂层致密,涂层孔隙率低,与基体的结合强度高,且涂层的硬度较高。     

卷筒扇形板表面HVOF喷涂技术与应用

针对热轧平整机组开卷机卷筒扇形板的防护,系统分析对比了渗氮、镀铬、等离子喷涂APS(Air Plasma Spraying)及超音速火焰喷涂(HVOF)等常用表面处理技术的特点。基于HVOF具有涂层结合强度高、硬度高、耐磨性能好、孔隙率低及可多次修复使用等优点,重点研究了两种粉末WC-12Co和WC-CrC-Ni经0°,15°,30°不同喷涂角度制备试样的显微形貌、硬度、沉积率、耐磨性等。确定了涂层粉末和最佳喷涂工艺参数,并将其用于卷筒扇形板的实际表面处理中,使用效果良好。     

A Comparison of Wear Due to Abrasion of WC–Ni Coatings on Aluminium Alloy Sprayed by HVOF and Detonation Gun

In this investigation, aluminum alloy is coated with WC–Ni layer deposited by detonation spraying and high velocity oxy fuel (HVOF) spraying. The important features of microstructure and hardness of the coating are characterized extensively. The wear rates of the coating due to abrasion are determined for different applied loads. The worn coatings are examined under scanning electron microscopy. A correlation is established between the wear rates of the coatings due to abrasion and hardness. The results show that abrasion action takes place by both particle rolling and particle sliding. Fracture of particles during abrasion increases wear rate. In general, the wear rate due to abrasion is higher for the coating deposited by detonation spraying than that of coating deposited by HVOF spraying.     

Optimizing High-Velocity Oxygen Fuel-Sprayed WC–17Co Coating Using Taguchi Experimental Design to Improve Tribological Properties

High-velocity oxy-fuel (HVOF) thermal spraying is one of the best methods for depositing conventional WC–Co cermets. The aim of the present work was to optimize the WC–17Co coating deposited using HVOF spraying process. Taguchi fractional factorial experimental design (L18) and ANOVA were used to optimize the process parameters. Seven factors (spray distance, oxygen flow rate, carrier gas flow rate, powder feed rate, coating thickness, substrate preheat temperature and grit type) were selected. Grit type had two levels, and the others had three levels. The coating properties measured were wear resistance, microhardness and roughness. Pin-on-disk wear tests were used for measuring wear. Scanning electron micrographs were used to investigate the cross sections of the coatings and the morphology of the as-sprayed coatings, and their relationship between the process parameters and energy-dispersive X-ray was used to analyze the coatings. In Taguchi method, “lower the better” quality was used for optimizing roughness and “higher the better” quality was used for optimizing wear resistance and microhardness. The most influential factor on increasing wear resistance and microhardness was powder feed rate and on reducing the roughness was oxygen flow rate. In addition, the influence of grit type on wear resistance and microhardness and the influences of grit type and substrate preheat temperature on the coating roughness were negligible.     

热喷涂WC—Co复合涂层的研究现状及展望

热喷涂WC—Co涂层由于具有硬度高及耐磨性能优良的特性作为耐磨涂层已得到了迅速的发展及广泛的应用。本文综述了国内外在利用热喷涂技术制备WC—Co复合涂层方面的研究进展;介绍了WC—Co热喷涂复合粉末的制备、各种热喷涂方法的工艺特点,比较了不同工艺方法制备的各种WC—Co涂层的组织结构及性能。综合研究表明：HVOF工艺更适合制备多峰及纳米结构WC—Co涂层;与传统WC—Co涂层比较,多峰和纳米结构WC—Co涂层在机械性能以及耐磨性能方面均有较大提高。     

低温超音速火焰喷涂纳米WC-10Co4Cr涂层的显微结构和性能

以纳米和微米WC-10Co4Cr粉末为热喷涂粉末,采用低温超音速火焰喷涂（LT-HVOF）和超音速火焰喷涂（HVOF）技术制备了WC-10Co4Cr涂层,采用SEM、XRD、和显微硬度仪等对LT-HVOF WC涂层显微结构和性能进行了表征.结果表明：n-WC涂层、lm-WC涂层的显微结构与普通超音速火焰喷涂WC涂层没有明显的区别,其主晶相为WC; m-WC涂层呈明显的层状结构,涂层中WC颗粒尖端发生了钝化和部分熔化,粒径变小,并形成了WC/的核壳结构;其主晶相为.n-WC涂层显微硬度较lm-WC涂层低,但其韧度高而使涂层的磨损失重最低;m-WC涂层的显微硬度和韧度最低,磨损失重最大.     

热喷涂WC-10Co4Cr涂层的研究现状

WC陶瓷涂层以其较高的硬度和优良的耐磨性能而被广泛的应用于各种耐磨保护涂层。文章综述了热喷涂WC-10Co4Cr涂层的主要制备方法及工艺现状;指出了其中最为适合制备WC-10Co4Cr粉末和涂层的技术方法,并总结了近年来热喷涂技术特别是超音速火焰喷涂技术制备WC-10Co4Cr涂层的主要研究进展;同时,通过对影响涂层组织和性能的主要因素和影响机理的分析,对热喷涂WC-10Co4Cr陶瓷涂层的研究趋势进行了展望,提出值得关注稀土元素对WC-10Co4Cr涂层的改性作用。     

Coatings Deposited by the High-Velocity Flame Spraying Method

The properties (porosity, hardness, wear resistance) of coatings obtained by high-velocity flame spraying were studied. It was shown that high-velocity spraying produces highly dense coatings (porosity below 3%) which have good abrasion resistance under extreme conditions: resistance to abrasive-erosion was 10-12 times better than that of uncoated steel. Abrasive wear resistance at low attack angles was obtained in coatings of maximum hardness, i.e., hardness above that of the abrasive. At high attack angles an optimum ratio of hardness to ductility is desired. The optimal structure for WC Co coatings is the so-called twice cemented hard alloy structure, in which granules or particles of WC Co are included within the cobalt binder. At large attack angles the concentration of carbide phase should exceed 50%, and at normal angles is optimally 20-30%.     

面向工程机械绿色再制造的超音速火焰喷涂碳化钨硬面涂层的性能

绿色再制造工程在上世纪八十年代国际上兴起,并成为发展最快的新型研究领域和新兴产业之一。本文利用超音速火焰喷涂技术制备WC-12Co涂层,探讨了该涂层在磨损失效的ZL50C型装载机驱动桥差速器的十字轴领域的应用可能性。通过光学显微镜、扫描电子显微镜、X射线、显微硬度计和拉伸测试对所制备的涂层进行了评定,以硬度为目标,所获的优化工艺参数为:丙烷压力为0.45MPa,流量为17L/min,氧气压力为0.65MPa,流量为167L/min,喷涂距离为275mm。通过优化工艺参数制备的WC-12Co涂层致密,孔隙率低于1%,涂层由WC、Co和部分分解的W2C等组成;涂层的显微硬度为1100HV0.1左右,结合强度超过63.7MPa。通过在十字轴的表面制备了厚度约500μm的WC-12Co涂层,恢复了轴的直径尺寸,并大大改善了十字轴的耐磨性,该类涂层适用于十字轴等耐磨工程机械零部件的再制造。