超音速喷涂技术及其应用

回顾了超音速喷涂技术的发展过程;总结了超音速火焰喷涂、超音速等离子喷涂、超音速电弧喷涂及冷喷涂等设备的结构和技术特点;介绍了超音速喷涂工艺及涂层特性;展望了该技术在制备纳米涂层方面的应用及发展前景。     

浅谈超音速火焰喷涂在汽车冲压模具上的应用

通过围绕超音速火焰喷涂在汽车模具上的应用,探讨在新形势下表面拉毛处理的新技术应用。     

超音速火焰喷涂及涂层性能简介

本文简要介绍了超音速火焰喷擦的原理、发展状态；比较了超音速火焰喷涂层、等离子喷涂层，爆炸喷涂层、自熔合金喷熔层以及电镀硬铬层的硬度和耐磨损性能；介绍了超音速火焰喷涂层的部份应用实例及其应用效果。     

超音速火焰喷涂(HVOF)技术的发展与工艺特点

介绍了超音速火焰喷涂技术的发展过程,未来的发展方向以及涂层的应用,详细比较了各种超音速火喷涂枪的工艺特点和涂层造价。此外,还对时速火焰喷涂层的性能进行了较的介绍。     

超音速火焰喷涂枪的研究

利用理论分析与实验相结合的方法,在比较和借鉴国外相近喷枪的基础上,对喷枪结构参数进行了选择,对喷枪的实际性能进行了估算。将在此基础上设计出的喷枪进行点火试验,得到的实测值与估算值吻合得很好。这证明了喷枪的结构设计合理,性能的估算比较准确,从而为设计和改进喷枪结构,提高喷枪的性能提供了可靠的理论依据。     

超音速火焰喷涂在汽车模具上的应用

分析了汽车冲压模具使用的工况条件,讨论了冲压模具的主要失效形式和汽车冲压件的主要缺陷,同时介绍了超音速火焰喷涂的原理、特点及应用优势。通过对超音速火焰喷涂技术在模具上的应用和效果分析得出,采用超音速火焰喷涂技术,可有效地提高模具的使用性能,消除冲压件表面的拉毛缺陷,从而延长模具的使用寿命。     

超音速火焰喷涂WC/Co涂层的组织性能研究

分析比较了等离子喷涂、超音速火焰喷涂的WC／Co涂层的形貌、显微组织、孔隙率、硬度、结合强度及其耐磨性。结果表明：超音速火焰喷涂涂层具有与粉末相近的相结构，与等离子喷涂相比涂层具有高的致密度、硬度和良好的耐磨性，涂层与基体结合情况也得到很大的改善。     

超音速火焰喷涂工艺对涂层耐磨性能的影响

采用起音速火焰喷涂工艺在Q235B基体上制备Co-Cr-WC涂层;利用MMW-1立式万能摩擦磨损试验机对涂层耐磨性能进行检测,并与Cr12模具钢试盘整体淬火、45钢试盘表面电孤喷涂70钢涂层、45钢试盘表面电孤喷涂1mm厚的3Cr13马氏体不锈钢涂层3种试样进行对比;利用金相显微镜、扫描电子显微镜对涂层磨痕进行观察.试...     

喷涂距离对超音速火焰喷涂 CoCrAlYTa 涂层组织性能的影响

采用超音速火焰喷涂技术制备CoCrAlYTa涂层,研究了喷涂距离对涂层相组成、孔隙率以及硬度、弯曲强度、高温抗氧化性能的影响。结果表明:喷涂距离在200～300 mm范围内时,随着喷涂距离的减小,涂层的致密度增加,孔隙率下降,显微硬度和弯曲结合强度增加,但相组成基本不变,主要由CoAl,AlCo2Ta和CoTa3相组成;涂层致密度越高,在高温氧化过程中,表面越易尽早形成连续氧化膜并促进涂层中Al元素的选择氧化,因此随着喷涂距离的减小,涂层的高温抗氧化性能逐渐增强。     

Application of HVOF thermal spraying to solve corrosion problems in the petroleum industry—an industrial note

Commercially available thermal spray coatings have seen limited use in corrosion applications due to the presence of interconnecting porosity and oxide networks. Use of vacuum chambers or post-treatments can eliminate most defects, but these methods are costly and impractical on a large scale. The ability to produce such high-quality coatings by thermal spraying in atmosphere and without post-treatments would offer important advantages as a means of building and repairing process equipment. A modified HVOF process using unique inert gas shrouding has resulted in highly dense, low-oxide coatings of metallic alloys. These coatings were extensively evaluated for severe petroleum industry corrosion applications in laboratory and plant testing, with exposures as long as 5 years. Coatings of corrosion-resistant alloys, such as type 316L stainless steel and Hastelloy C-276, were shown to act as true corrosion barriers. They were protective to underlying base metals in severe environments and in most cases exhibited corrosion resistance comparable to the corresponding wrought alloy. The process was scaled up for on-site plant use and successfully applied to numerous corrosion problems in petroleum industry plant equipment. Significant technical and economic advantages can be realized by use of thermal spray coatings to solve plant equipment problems.     

HVOF喷涂Ni基涂层性能的研究

采用超音速火焰喷涂技术（HVOF）制备了3种镍基涂层，并对涂层的性能进行测试。结果表明：烧结粉末Ni60制备的涂层结合强度达44．6MPa、显微硬度963．8HV，均明显优于包覆粉末Ni包C、Ni包MoS2制备的涂层；Ni包C涂层孔隙率最高，达5．4％，并含有许多的未熔软质相；涂层中的镍起粘结作用，能显著提高涂层的结合强度和显微硬度；起减磨作用的MoS2和C相会明显降低涂层的结合强度。     

超音速火焰喷涂FeCrSiB涂层的腐蚀行为

采用超音速火焰(high velocity oxygen fuel,HVOF)喷涂技术在Q235钢基体上制备了FeCrSiB合金涂层.利用X射线衍射仪、扫描电子显微镜、电化学工作站等设备对涂层的显微组织结构和耐腐蚀性进行了研究.结果表明,采用HVOF喷涂技术制备的FeCrSiB涂层结构致密,孔隙率为0.65%,与基体结合良好.FeCrSiB涂层在3.5%NaCl溶液、1 mol/L HCl溶液和1 mol/L NaOH溶液中都经历了活性溶解-钝化-过钝化的过程,且该涂层在3.5%NaCl溶液和1 mol/L HCl溶液中的耐腐蚀性能要优于镀铬层,在1 mol/L NaOH溶液中的耐腐蚀性能低于镀铬层.     

Effect of spraying distance on the microstructure and mechanical properties of a Colmonoy 88 alloy deposited by HVOF thermal spraying

The present work has been conducted in order to determine systematically the influence of the spraying distance on the microstructure and mechanical properties of a Colmonoy 88 alloy deposited by means of HVOF thermal spray onto a SAE 1045 steel substrate. The spray distance varied between 380-470 mm and the evaluation of the deposits characteristics and properties was carried out both on their surface and on cross section. Both hardness and elastic modulus of the coatings were determined according to the model of Oliver and Pharr. The yield strength of the coatings was also estimated following the methodology developed by Zeng and Chiu for the analysis of the loading and unloading curves obtained from nanoindentation experiments, as well as from classical static spherical indentation tests. The microstructural analysis indicated a significant increase in the unmelted particles volume fraction and the development of interlamellar microcracks as the spraying distance increases, leading to a decrease in the elastic modulus of the coatings. Both hardness and elastic modulus showed an anisotropic behavior and were found to be higher on the cross section of the coating than on the deposition plane. A satisfactory comparison between the predicted and experimental values of the coatings yield strength was observed for all the conditions investigated.     

铁基非晶基涂层的HVOF制备及耐腐蚀性能(英文)

以工业原材料制备的铁基非晶合金、镍铬合金、碳化钨颗粒的混合粉末为原材料,采用高速火焰喷涂技术制备铁基非晶基涂层。通过分析铁基非晶基涂层分别在1 mol/L盐酸、氯化钠、硫酸和氢氧化钠溶液中的动态极化特性,研究其腐蚀阻抗。采用扫描电子显微镜(SEM)分析涂层的腐蚀形貌。结果表明:铁基非晶基涂层具有优良的耐蚀性能,而且在含氯离子溶液中,表现出比304L奥氏体不锈钢更高的腐蚀阻抗。在1 mol/L盐酸溶液中,铁基非晶基涂层的腐蚀电流密度和钝化电流密度分别为132.0μA/cm2和9.0 mA/cm2,在1 mol/L氯化钠溶液中分别为2.5μA/cm2和2.3 mA/cm2,且表现出一个宽的自钝化区间。其优异的耐蚀性能表明铁基非晶基粉末可以作为一种耐腐蚀、耐磨损的工程材料。     

Development and trends in HVOF spraying technology

Three actual trends in development of HVOF spraying technology are described and discussed. The trends concern application fields as well as gun and feedstock characteristics. At the example of demountable draw bars it is shown that HVOF sprayed cermet coatings are capable to protect light weight material components subject to dynamical load against wear without detraction of fatigue strength. Personnel and production time savings can be exploited. High deposition efficiency at considerable powder feed rate, high density and negligible oxygen content in corrosion protective iron or nickel based coatings is achieved for spraying with newly developed HVOF guns operating at increased combustion chamber pressures. Also spraying of highly reactive materials like titanium under atmospheric conditions becomes feasible. A major obstacle for industrial use of respective coatings is the lack of adapted characterisation methods that permit to ascertain corrosion protective function. Ultrafine powder feedstock is used in order to reduce overall costs of wear protective cermet coatings due to the possibility to finish coatings by comparatively cheap belt grinding. However, it is shown that the replacement of coatings produced with conventional powder size fractions requires careful consideration of the particular tribological system. While cermet coatings produced with ultrafine powders outperform conventional coatings for sliding wear conditions, their capability to withstand dry abrasive wear stress is poor. The benefits concerning coating production costs may be outweighed by significantly decreased component life time.     

Mathematical modelling of Inconel 718 particles in HVOF thermal spraying

High velocity oxygen fuel (HVOF) thermal spray technology is able to produce very dense coating without over-heating powder particles. The quality of coating is directly related to the particle parameters such as velocity, temperature and state of melting or solidification. In order to obtain this particle data, mathematical models are developed to predict particle dynamic behaviour in a liquid fuelled high velocity oxy-fuel thermal spray gun. The particle transport equations are solved in a Lagrangian manner and coupled with the three-dimensional, chemically reacting, turbulent gas flow. The melting and solidification within particles as a result of heat exchange with the surrounding gas flow is solved numerically. The in-flight particle characteristics of Inconel 718 are studied and the effects of injection parameters on particle behavior are examined. The computational results show that the particles smaller than 10 μm undergo melting and solidification prior to impact while the particle larger than 20 μm never reach liquid state during the process.     

超音速火焰喷涂CoCrW涂层热震过程中的裂纹扩展行为

为研究CoCrW涂层的抗冷热冲击性能,采用JP5000型超音速火焰喷涂设备在高温合金表面制备了该涂层,分析了裂纹在热震过程中的扩展行为。结果表明,在800 ℃保温,25 ℃水淬的热循环条件下,经过40次热震后,涂层表面均匀地分布着网状裂纹,截面上存在垂直裂纹,但未出现涂层脱落现象;在裂纹与基体、涂层界面交汇处生成了弥散分布的以Al2O3为主要成分的氧化物。分析认为,热应力和组织应力是裂纹产生和扩展的主要驱动力,但裂纹吸收了热震过程中产生的能量,避免了应力集中,有利于提高涂层的抗热震性能。界面处弥散分布的氧化物降低了涂层与基体的结合强度,热震试验最终的失效形式可能是界面处涂层的剥离。     

启闭机活塞杆表面超音速火焰喷涂WC-10Co-4Cr涂层的性能

采用超音速火焰热喷涂技术在启闭机活塞杆材料40Cr钢表面制备WC-10Co-4Cr涂层,通过扫描电镜、X射线衍射仪、显微硬度计、摩擦磨损试验机、电化学工作站等手段对涂层的基本性能进行了研究并与基材的性能进行了对比分析。结果表明:涂层的显微硬度为1 330HV0.3是基体的3.9倍,摩擦因数小于基体,其耐磨性能达到基体的145倍,涂层的耐腐蚀性能较基体也有大幅提高,并且涂层致密度高孔隙率低于0.45%,与基体之间的结合强度高于70.37MPa。将涂层应用于活塞杆表面可以大幅提高其表面性能,特别是耐磨性能及耐腐蚀性能,使得活塞杆的使用寿命提高为常用电镀铬的3倍以上。     

高速电弧喷涂技术在工程中的应用与展望

高速电弧喷涂(HVAS)技术具有生产效率高、涂层性能优异等诸多优点，可以在防腐蚀、抗高温等工作场合中得到应用；在电厂的建设与维护、石油工程的建设与维修等诸多领域都具有良好的应用前景。