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采用YAG脉冲激光器对电弧喷涂Fe基非晶涂层进行激光重熔处理。通过X-ray、SEM、冲蚀磨损和硬度测量仪等检测手段,研究非晶合金涂层在重熔后的组织结构、硬度和抗冲蚀性能的变化。结果表明:电弧喷涂铁基非晶合金在激光重熔后发生晶化,重熔层非晶含量随功率升高而降低。激光重熔基本消除了非晶涂层的层状结构、残余的气孔和裂纹,平整了涂层表面,提高了涂层韧性,显著改善了涂层的抗冲蚀性能。对喷涂1层的非晶涂层进行重熔时,重熔层的冲蚀磨损量约为喷涂层的1/10,约为基体Q345的1/5。对喷涂5层的非晶涂层进行重熔时,选择0. 1 kW低功率有利于获得较好的抗冲蚀性能。当涂层较厚而激光重熔未熔透时,涂层内应力会随激光功率增大而升高,并导致涂层开裂。当5层非晶涂层被熔透时,抗冲蚀性能显著提高。 相似文献
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利用等离子喷涂方法制备Al2O3-40% TiO2涂层,对涂层进行激光重熔处理.分别对等离子喷涂层和激光重熔涂层进行耐冲蚀磨损性能试验,研究了激光重熔对Al2O3-40% TiO2等离子喷涂层耐冲蚀性能的影响.结果表明,激光重熔消除了Al2O3-40% TiO2等离子喷涂层的层状结构,使得等离子喷涂层中γ-Al2O3转变为α-Al2O3,形成了α-Al2O3+TiAl2O5稳定结构.激光重熔后的涂层组织致密均匀、硬度高,具有冶金结合特征,使得耐冲蚀性能得到极大提高,其磨损特征为冲蚀粒子冲击作用下产生的裂纹、破碎与块状剥落. 相似文献
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目的提高电弧喷涂含非晶相Fe基涂层的抗冲蚀及耐腐蚀性能。方法采用YAG脉冲激光器对电弧喷涂含非晶相Fe基涂层进行激光重熔处理。通过X-ray、SEM、冲蚀磨损和电化学等检测手段,研究该涂层重熔后的组织结构、冲蚀磨损性能和耐腐蚀性能。结果电弧喷涂含非晶相Fe基涂层经激光重熔后发生了晶化,并随着功率的增加,非晶含量降低,硬度也降低。重熔后,涂层与基体的结合方式由之前的机械咬合转变为冶金结合,涂层的致密度明显提高,组织缺陷减少。与喷涂层相比,0.3k W激光重熔涂层的抗冲蚀性能在30°攻角下可提高3倍,在90°攻角下可提高将近6倍。重熔层的冲蚀磨损机制在低冲角时以显微切削为主,高冲角时则以挤压破碎为主。随着激光功率的增加,重熔涂层的抗冲蚀性能降低。同时,在3.5%NaCl溶液中,重熔层的耐蚀性能随重熔激光功率的提高而提高,并且重熔层的腐蚀电流密度比喷涂层明显降低。结论激光重熔不但改善了电弧喷涂含非晶相Fe基涂层与基体间的结合状态,同时也增强了涂层的耐蚀和耐磨性能,是一种有效提升涂层性能的后处理工艺。 相似文献
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分别采用等离子喷涂和等离子喷涂一激光重熔复合工艺在TiAl合金表面制备了热障涂层,研究了两种涂层在850℃:下75%Na2SO4+25%NaCl(质量分数)熔融盐中的热腐蚀行为,进而分析激光重熔工艺对等离子喷涂热障涂层耐热腐蚀性能的影响。结果表明:激光重熔热障涂层可以有效地阻止熔融盐腐蚀介质进入涂层发生腐蚀,具有更优的抗热腐蚀性能和使用寿命。 相似文献
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激光表面重熔对ZrO_2-8wt%Y_2O_3热障涂层组织与抗热震性能的影响 总被引:2,自引:1,他引:1
采用等离子喷涂设备在H13热作模具钢表面制备氧化钇部分稳定的氧化锆(ZrO2-8 wt%Y2O3)热障涂层,并用CO2横流激光器对热障涂层进行表面重熔处理,并采用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、热震试验等手段研究激光重熔前后热障涂层的微观结构及其抗热震性能的变化。结果表明,重熔前后涂层均由四方结构钇锆氧化物和立方相的氧化锆组成,重熔后涂层结晶度增加,晶粒有长大现象。激光重熔后涂层产生明显分层,表层组织孔隙和裂纹明显减少,裂纹呈网状且沿晶界分布,重熔涂层内部仍保持等离子喷涂典型结构。激光重熔后涂层孔隙率降低了67%,涂层的抗热震性能也显著提高。 相似文献
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《中国腐蚀与防护学报》2019,(1)
研究了等离子喷涂热障涂层(TBCs)和激光重熔热障涂层在75%Na_2SO_4+25%NaCl (质量分数)熔盐中不同时间下的热腐蚀性能。通过SEM和XRD分析了热腐蚀后两种热障涂层表面和截面的微观形貌和物相组成。结果表明,未经过激光重熔的涂层在前50 h的热腐蚀过程中重量增加;在后续腐蚀过程中重量减小,100 h时腐蚀减重达到了6.8 mg/cm~2,同时出现了涂层剥落的现象;表面物相分析检测到ZrO_2和Y_2(SO_4)_3相。激光重熔热障涂层在热腐蚀过程中重量一直在增加;后期阶段趋于平缓,100 h时腐蚀增重为3.7 mg/cm~2;表面物相分析仅检测到ZrO_2相。激光重熔改善了热障涂层的抗热腐蚀性能。 相似文献
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激光熔敷抗氧化与隔热涂层组织结构及高温性能研究 总被引:8,自引:1,他引:7
对镍基高温合金上激光重熔等离子喷涂热障涂层进行研究,并对其高温性能进行了测试.结果表明,ZrO2陶瓷涂层为细化柱状晶,柱状晶晶界处含Al、Ti等元素,NiCoCrAlY结合层为奥氏体胞晶.相分析确定形成了立方和四方混合ZrO2.其高温氧化和热循环性能比等离子喷涂形成的热障涂层显著提高 相似文献
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A plasma-sprayed 8 wt.% yttria partially stabilized zirconia coating doped with 3 wt.% SiO2 was remelted by laser. The microstructure of the as-sprayed and laser-remelted coatings was characterized by scanning electron
microscopy (SEM), electron probe microanalysis (EPMA), transmission electron microscopy (TEM), and x-ray diffraction (XRD).
The effect of laser remelting on the hardness, wear resistance, and thermal shock resistance of the coatings was also studied.
The laser-remelted coating consists of fine solidification grains without the presence of pores and cracks. The elements are
uniformly distributed in the laser-remelted coating. Nontransformable tetragonal (t′) phase is predominant in the laser-remelted coating with a small amount of cubic phase. Laser remelting greatly enhanced
the hardness, wear resistance, and thermal shock resistance of the coatings, and should find more applications. 相似文献
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Chaoping Jiang Hong Chen Gui Wang Yongnan Chen Yazhe Xing Chunhua Zhang Matthew Dargusch 《Journal of Thermal Spray Technology》2017,26(4):778-786
Amorphous coating technology is an attractive way of taking advantage of the superior properties of amorphous alloys for structural applications. However, the limited bonds between splats within the plasma-sprayed coatings result in a typically lamellar and porous coating structure. To overcome these limitations, the as-sprayed coating was treated by a laser-remelting process. The microstructure and phase composition of two coatings were analyzed using scanning electron microscopy with energy-dispersive spectroscopy, transmission electron microscopy, and x-ray diffraction. The wear resistance of the plasma-sprayed coating and laser-remelted coating was studied comparatively using a pin-on-disc wear test under dry friction conditions. It was revealed that the laser-remelted coating exhibited better wear resistance because of its defect-free and amorphous-nanocrystalline composited structure. 相似文献
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采用等离子喷涂技术在TiAl合金表面制备了MCrAlY涂层,并用激光重熔工艺对涂层进行处理,研究了TiAl合金、等离子喷涂MCrAlY涂层及激光重熔MCrAlY涂层850℃下75%Na2SO4+25%NaCl(质量分数)混合盐浸泡热腐蚀性能,分析了不同试样的热腐蚀破坏机理,并讨论了激光重熔处理对涂层热腐蚀性能的影响.结果表明,等离子喷涂MCrAlY涂层能显著提高TiAl合金的耐热腐蚀性能,经过激光重熔后可进一步提高其耐热腐蚀性能.MCrAlY涂层在高温熔盐中的热腐蚀发生的是表面氧化反应和内部硫化反应,主要生成Al2O3,Cr2O3,NiO,NiCr2O4,Ni3S2及CrS等腐蚀产物. 相似文献
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J. Tuominen P. Vuoristo T. Mäntylä M. Kylmälahti J. Vihinen P. H. Andersson 《Journal of Thermal Spray Technology》2000,9(4):513-519
Thermal spray processes are widely used to protect materials and components against wear, corrosion and oxidation. Despite
the use of the latest developments of thermal spraying, such as high-velocity oxy-fuel (HVOF) and plasma spraying, these coatings
may in certain service conditions show inadequate performance,e.g., due to insufficient bond strength and/or mechanical properties and corrosion resistance inferior to those of corresponding
bulk materials. The main cause for a low bond strength in thermalsprayed coatings is the low process temperature, which results
only in mechanical bonding. Mechanical and corrosion properties typically inferior to wrought materials are caused by the
chemical and structural inhomogeneity of the thermal-sprayed coating material. To overcome the drawbacks of sprayed structures
and to markedly improve the coating properties, laser remelting of sprayed coatings was studied in the present work. The coating
material was nickel-based superalloy Inconel 625, which contains chromium and molybdenum as the main alloying agents. The
coating was prepared by HVOF spraying onto mild steel substrates. High-power continuous wave Nd:YAG laser equipped with large
beam optics was used to remelt the HVOF sprayed coating using different levels of power and scanning speed. The coatings as-sprayed
and after laser remelting were characterized by optical microscopy and scanning electron microscopy (SEM). Laser remelting
resulted in homogenization of the sprayed structure. This strongly improved the performance of the laser-remelted coatings
in adhesion, wet corrosion, and high-temperature oxidation testing. The properties of the laser-remelted coatings were compared
directly with the properties of as-sprayed HVOF coatings and with plasma-transferred arc (PTA) overlay coatings and wrought
Inconel 625 alloy. 相似文献
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等离子喷涂涂层中不可避免存在残余应力和微裂纹,为了减少TiN涂层的残余应力,在等离子喷涂TiN涂层中添加了Ni/G,在45#钢表面制备了TiN-Ni/G复合涂层。研究了Ni/G含量对涂层的微观组织、显微硬度以及抗冲蚀性能的影响,并分析了涂层在不同pH值泥浆中的冲蚀机理。结果表明:TiN-Ni/G复合涂层的平均显微硬度值在9800 MPa(1000 HV0.2)左右,在质量分数5%NaCl泥浆冲蚀过程中涂层受到SiO2颗粒的冲击以及溶液的腐蚀;pH=10的NaOH泥浆对涂层冲蚀表现为SiO2冲击作用。涂层在含NaOH泥浆中的质量损失较中性溶液有明显减少,在2种冲蚀液中Ni/G质量分数为11%时涂层都表现出良好的抗冲蚀性能。 相似文献
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Laser remelting was applied to plasma-sprayed Al-Si coating on magnesium alloy AZ91D to improve corrosion performance. Both salt spray testing and potentiodynamic polarization measurement in 3.5% NaCl solution indicated that laser-remelted Al-Si coating acquired better corrosion resistance than AZ91D and plasma-sprayed Al-Si coating. The decreasing order of the corrosion rates are AZ91D base metal, sprayed Al-Si coating and laser-remelted Al-Si coating. The fine Al-Si eutectic matrix in the laser-remelted microstructure contributed to the improved corrosion performance relative to the AZ91D and the plasma-sprayed coating. The predominant corrosion mechanisms in AZ91D, plasma-sprayed coating and laser-remelted coating are intra-granular corrosion, crevice corrosion and the combined pitting and galvanic corrosion, respectively. 相似文献
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为了提高等离子喷涂WC颗粒增强镍基涂层的性能,采用激光重熔工艺对涂层进行处理,研究了激光重熔对涂层微观组织和性能的影响.用扫描电镜(SEM)、X射线衍射仪(XRD)和显微硬度计分析了涂层表面形貌、微观结构、相组成和显微硬度,同时对涂层的高温摩擦磨损特性进行了考察.结果表明,激光重熔消除了等离子喷涂层的层片状结构、孔隙等缺陷,涂层致密度提高;另外在激光高能量密度作用下,WC颗粒部分熔化,并在周围析出枝晶结构.激光重熔处理后涂层的显微硬度明显提高,其磨损性能也显著高于原等离子喷涂层. 相似文献
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J. Tuominen P. Vuoristo T. Mäntylä S. Ahmaniemi J. Vihinen P. H. Andersson 《Journal of Thermal Spray Technology》2002,11(2):233-243
Thermal spray processes are widely used to deposit high-chromium, nickel-chromium coatings to improve high temperature oxidation
and corrosion behavior. However, despite the efforts made to improve the present spraying techniques, such as high-velocity
oxyfuel (HVOF) and plasma spraying, these coatings may still exhibit certain defects, such as unmelted particles, oxide layers
at splat boundaries, porosity, and cracks, which are detrimental to corrosion performance in severe operating conditions.
Because of the process temperature, only mechanical bonding is obtained between the coating and substrate. Laser remelting
of the sprayed coatings was studied in order to overcome the drawbacks of sprayed structures and to markedly improve the coating
properties. The coating material was high-chromium, nickel-chromium alloy, which contains small amounts of molybdenum and
boron (53.3% Cr, 42.5% Ni, 2.5% Mo, 0.5% B). The coatings were prepared by HVOF spraying onto mild steel substrates. A high-power,
fiber-coupled, continuous-wave Nd:YAG laser equipped with large beam optics was used to remelt the HVOF-sprayed coating using
different levels of scanning speed and beam width (10 or 20 mm). Coating that was remelted with the highest traverse speed
suffered from cracking because of the rapid solidification inherent to laser processing. However, after the appropriate laser
parameters were chosen, nonporous, crack-free coatings with minimal dilution between coating and substrate were produced.
Laser remelting resulted in the formation of a dense oxide layer on top of the coatings and full homogenization of the sprayed
structure. The coatings as sprayed and after laser remelting were characterized by optical and electron microscopy (OM, SEM,
respectively). Dilution between coating and substrate was studied with energy dispersive spectrometry (EDS). The properties
of the laser-remelted coatings were directly compared with properties of as-sprayed HVOF coatings. 相似文献
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Sputtered Ni + TiB2 coatings have been shown to protect Inconel* 718 and Ti-6A1-4V substrates from solid particle erosion. However, before new
erosion-resistant coatings can be efficiently designed, it is essential that the role of mechanical properties in determining
erosion resistance be fully understood. In this investigation, nanoindentation techniques were used to quantify the effects
of substrate preparation, coating composition, and sputtering process parameters on the elastic moduli and indentation hardness
of thin coatings deposited on Ti-6A1-4V and Inconel 718 substrates. The influence of these parameters on coating adhesion
was determined using a conventional scratch test. Elastic moduli, indentation hardnesses, and coating adhesion were correlated
with erosion behavior. The erosion resistance of those coatings that exhibited microscopic ductility is dependent on the nodule
diameter and coating properties such as hardness, elastic modulus, and fracture toughness.
Inconel 718 is a trademark of The International Nickel Co. 相似文献