共查询到19条相似文献,搜索用时 78 毫秒
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等离子喷涂陶瓷涂层具有高硬度、高熔点、耐磨、耐腐蚀、隔热、绝缘等特点,巳成为近年来热喷涂行业研究发展的重要方向,并日益广泛地应用于零部件的表面防护与强化。 相似文献
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等离子喷涂纳米陶瓷涂层研究 总被引:1,自引:0,他引:1
从纳米喂料的制备、纳米陶瓷涂层的制备及其结构和特性三方面评述了等离子喷涂纳米陶瓷涂层研究的进展,探讨了等离子喷涂纳米陶瓷涂层研究中存在的主要问题,并展望了等离子喷涂纳米陶瓷涂层的发展前景。 相似文献
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等离子喷涂NiCrCoAlY涂层氧化控制研究 总被引:1,自引:0,他引:1
利用等离子喷涂技术制备了NiCrCoAlY粒子和涂层,研究了等离子喷涂过程中NiCrCoAlY粒子的氧化行为以及屏蔽气体对NiCrCoAlY涂层抗高温氧化性能的影响。结果表明,粒子在飞行过程中存在对流氧化和扩散氧化两种氧化机制,对NiCrCoAlY粒子来说,在距喷嘴55 mm以内的射流中心处以对流氧化为主,在距离喷嘴55 mm以外将以扩散氧化为主;除飞行中的氧化外,粒子在喷涂过程中还发生形成涂层后的氧化,NiCrCoAlY粒子以飞行中的氧化为主;添加屏蔽气体能减少喷涂过程中涂层的氧化,提高涂层的抗高温氧化性能 相似文献
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采用等离子喷涂技术制备了WC-Co涂层,所采用2种喂料分别为普通微米材料和混合纳米粒子的材料.分析了涂层的显微形貌、物相成分以及显微硬度、耐磨性等.研究结果表明:喷涂态的纳米WC粒子混合WC-Co涂层中的WC晶粒尺寸小于100 nm.纳米WC粒子混合涂层晶粒尺寸更小,WC颗粒分布更加均匀.WC颗粒的弥散强化和细晶强化作用使得涂层韧性、塑性更好.减缓了应力的集中,使微裂纹的产生和扩展几率降低.纳米WC粒子混合涂层更易生成高硬度的η1相以及立方结构物质,改善了涂层的塑性,使滑移方向更多,提高了涂层抵抗磨损的能力.纳米WC粒子混合涂层的细晶强化效应使得WC颗粒的接触数量更多,提高了涂层的硬度.普通涂层的磨损表面存在很多细小的裂纹,容易产生脆性断裂.纳米WC粒子混合涂层韧性较好,抗磨损能力更强. 相似文献
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This paper describes the formation process of nanostructured alumina coatings and the injection system obtained by suspension
plasma spraying (SPS), an alternative to the atmospheric plasma spraying technique in which the material feedstock is a suspension
of the nanopowder to be sprayed. The nanoscale alumina powders (d ≈ 20 nm) were dispersed in distilled water or ethanol and injected by a peristaltic pump into plasma under atmospheric conditions.
Optical microscopy (OM), scanning electron microscopy (SEM), and x-ray diffraction (XRD) analyses were performed to study
the microstructure of the nanostructured alumina coatings. The results showed that the nanoscale alumina powders in suspension
were very easily adsorbed at the inner surface of injection, which caused the needle to jam. The rotation of the pump had
a great effect on the suspension injection in the plasma. The very small resistance of the thin plasma boundary layer near
the substrate can drastically decrease the impacting velocity of nanosize droplets. The concentration of suspension also has
a significant influence on the distribution of the size of the droplet, the enthalpy needed for spraying suspension, and the
roughness of the coating surface. The phase structures of alumina suspension coatings strongly depend on the plasma spraying
distance. A significant nanostructured fine alumina coating was obtained in some areas when ethanol was used as a solvent.
The microstructures of the coating were observed as a function of the solvent and the spraying parameters. 相似文献
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R. Etchart-Salas V. Rat J. F. Coudert P. Fauchais N. Caron K. Wittman S. Alexandre 《Journal of Thermal Spray Technology》2007,16(5-6):857-865
Direct current Suspension Plasma Spraying (SPS) allows depositing finely structured coatings. This article presents an analysis
of the influence of plasma instabilities on the yttria-stabilized suspension drops fragmentation. A particular attention is
paid to the treatment of suspension jet or drops according to the importance of voltage fluctuations (linked to those of the
arc root) and depending on the different spray parameters such as the plasma forming gas mixture composition and mass flow
rate and the suspension momentum. By observing the suspension drops injection with a fast shutter camera and a laser flash
sheet triggered by a defined transient voltage level of the plasma torch, the influence of plasma fluctuations on jet or drops
fragmentation is studied through the deviation and dispersion trajectories of droplets within the plasma jet.
This article is an invited paper selected from presentations at the 2007 International Thermal Spray Conference and has been
expanded from the original presentation. It is simultaneously published in Global Coating Solutions, Proceedings of the 2007 International Thermal Spray Conference, Beijing, China, May 14-16, 2007, Basil R. Marple, Margaret M. Hyland, Yuk-Chiu Lau, Chang-Jiu Li, Rogerio S. Lima, and Ghislain
Montavon, Ed., ASM International, Materials Park, OH, 2007. 相似文献
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D. Zois A. Lekatou M. Vardavoulias I. Panagiotopoulos A. Vazdirvanidis 《Journal of Thermal Spray Technology》2008,17(5-6):887-894
Nanostructured and conventional Al2O3 powders have been plasma sprayed to produce coatings. The parameters for retaining a fraction of the nanostructure were investigated. Dissimilarities were observed between the two types of coating, regarding properties and phase proportions, which are related with the different percentages of semimolten particles in the coatings. The nanocoatings retained a higher percentage of semimolten particles than the conventional coatings owing to the higher porosity of the nanoparticle agglomerates. The molten part of both conventional and nanostructured coatings consisted of γ-Al2O3 of columnar morphology. In order to investigate the mechanism of the melting front advance into the particle interior, the particles were sprayed directly into deionized water. The nanoparticles mainly formed hollow spheres, whereas the conventional particles mainly formed compact spheres. The internal porosity of the solidified nanoparticle agglomerates, which affected the overall coating porosity and, consequently, coating properties such as hardness, adhesion, and surface roughness, was linked to the hollow sphere phenomenon. 相似文献
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Preparation of Al/SiC Composite Coatings on Surface of Aluminum Alloy by Atmospheric Plasma Spraying
对铝合金表面等离子喷涂制备Al/SiC复合涂层进行了研究,探索了SiC体积分数对复合粉末的沉积行为以及Al/SiC复合涂层性能的影响规律。研究发现,在等离子焰流中,纯SiC发生降解和氧化。SiC含量越高,等离子喷涂沉积Al/SiC复合涂层越困难,纯SiC沉积后与基体粘结层之间存在裂纹;SiC含量越高,Al/SiC复合涂层硬度越高。Al/SiC (50:50)复合涂层厚度70 μm,显微硬度达到3690 MPa,对铝合金表面起到强化效果 相似文献
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等离子喷涂金属/陶瓷梯度热障涂层研究进展 总被引:1,自引:0,他引:1
热障涂层在众多领域具有重要的应用价值,但基体与涂层的物理性能不匹配是遏制其服役性能和寿命提高的主要原因。金属/陶瓷梯度热障涂层通过逐渐改变涂层内部的成分、结构,可有效地改善基体和涂层因物理性能突变而导致的界面失效问题。首先介绍了金属/陶瓷梯度热障涂层对比于双层热障涂层的独特微观结构,并简要分析了其具有明显性能优势的原因。随后总结了金属/陶瓷梯度热障涂层残余应力的具体分布、影响因素和模拟模型优化现状,重点从优化涂层制备工艺、改进喷涂技术、改善涂层设计三个方面,介绍了改善涂层性能的研究进展。其中优化球磨和喷涂工艺参数、模拟研究喷涂过程、改进喷涂技术的方式是通过提高涂层质量来提升其物理性能,而改变涂层成分分布形式、涂层层数和厚度主要是通过改善涂层残余应力分布和水平来提升其抗热失效能力。最后提出了进一步优化模拟模型、改进喷涂技术、创新涂层设计和完善机理研究,是未来等离子喷涂金属/陶瓷梯度热障涂层的重点研究方向。 相似文献
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Alexandre Guignard Georg Mauer Robert Va?en Detlev St?ver 《Journal of Thermal Spray Technology》2012,21(3-4):416-424
In the field of thermal barrier coatings (TBCs) for gas turbines, suspension plasma sprayed (SPS) submicrometer-structured coatings often show unique mechanical, thermal, and optical properties compared to conventional atmospheric plasma sprayed ones. They have thus the potential of providing increased TBC performances under severe thermo-mechanical loading. Experimental results showed the capability of SPS to obtain yttria stabilized zirconia coatings with very fine porosity and high density of vertical segmentation cracks, yielding high strain tolerance, and low Young??s modulus. The evolution of the coating microstructure and properties during thermal cycling test at very high surface temperature (1400?°C) in our burner rigs and under isothermal annealing was investigated. Results showed that, while segmentation cracks survive, sintering occurs quickly during the first hours of exposure, leading to pore coarsening and stiffening of the coating. In-situ measurements at 1400?°C of the elastic modulus were performed to investigate in more detail the sintering-related stiffening. 相似文献
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超音速等离子喷涂WC/Co纳米结构涂层性能研究 总被引:10,自引:1,他引:10
采用超音速等离子喷涂设备分别制备了含纳米结构和普通结构的WC/Co涂层。研究了2种涂层的结合强度、显微硬度和摩擦磨损性能,并用扫描电镜(SEM)和透射电镜(TEM)对涂层喂料(纳米WC/Co粉体)、涂层表面形貌和晶粒结构进行了分析。结果表明:含纳米结构涂层的性能优于普通的WC/Co喷涂涂层,纳米晶粒细晶强化是涂层性能提高的主要原因。 相似文献
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Leszek Łatka Andrea Cattini Didier Chicot Lech Pawłowski Stefan Kozerski Fabrice Petit Alain Denoirjean 《Journal of Thermal Spray Technology》2013,22(2-3):125-130
Plasma generated by the SG-100 torch was applied to spray suspension formulated with the use of ZrO2 + 8 wt.% Y2O3 (8YSZ) and ZrO2 + 24 wt.% CeO2 + 2.5 wt.% Y2O3 (24CeYSZ) as solid phases. The suspensions were formulated with the use of 20 wt.% solid phase, 40 wt.% water, and 40 wt.% ethanol. The plasma spray parameters were optimized by keeping constant: (a) the electric power of 40 kW and (b) the working gas compositions of 45 slpm for Ar and 5 slpm for H2. On the other hand, the spray distance was varied from 40 to 60 mm and the torch linear speed was varied from 300 to 500 mm/s. The coatings were sprayed onto stainless steel substrates, and their thicknesses were in the range from 70 to 110 μm. The coating microstructures were analyzed with a scanning electron microscope. Mechanical properties were tested with the different methods including the indentation and scratch tests. The indentation test, carried out with various loads ranging from 100 to 10,000 mN, enabled to determine elastic modulus and Martens microhardness. Young’s modulus of the coatings was in the range of 71-107 GPa for 8YSZ and 68-130 GPa for 24CeYSZ coatings. The scratch test enabled the authors to find the scratch macrohardness. 相似文献
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超音速火焰喷涂纳米结构涂层研究进展 总被引:1,自引:0,他引:1
超音速火焰(High Velocity Oxy -Fuel,简称HVOF)喷涂具有高速和相对较低的温度两个重要特征,能够获得比普通火焰喷涂或等离子喷涂(Plasma Spray,简称PS)结合强度更高的致密涂层.纳米材料具有独特的表面效应、体积效应及量子尺寸效应,其电学、力学、磁学、光学和热学等性能产生了惊人的变化.随着材料科学技术的深入发展, 在实际生产和生活中运用性能优良的纳米材料倍受人们关注,其中,采用热喷涂技术制备纳米结构涂层是构筑纳米结构材料的最具前途的方法之一.从目前国内外的情况来看,HVOF喷涂纳米结构涂层技术的研究取得了较大的进展.综合国内外文献,总结了HVOF喷涂制备纳米结构涂层的研究现状,着重阐述了热喷涂纳米涂层的基本过程和结合机理,指出了利用HVOF喷涂纳米结构涂层存在的问题,并对热喷涂纳米结构涂层的发展前景作了展望. 相似文献