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以纯氧氯化锆、氧化钇和硝酸为原料,以碳酸铵沉淀剂,采用共沉淀法制备碳酸锆与碳酸钇的混合物,经喷雾干燥制粒、热处理后得到纳米YPSZ团聚粉末.由等离子喷涂方法制备了YPSZ涂层,用XRD、SEM等分析手段观察和确定涂层的物相组成和显微结构. 相似文献
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研究了不同Ce掺杂量对La2Zr2O7相结构稳定性的影响,确定了Ce原子掺杂量为5.45%的CeO2改性La2Zr2O7涂层(CLZ).研究了采用大气等离子喷涂制备的涂层与原始粉末化学成分计量比偏离情况.经共沉淀制粉、喷雾干燥团聚造粒、大气等离子喷涂制备了Ce原子掺杂量为5.45%的新型纳米CLZ热障涂层,研究了涂层的长期组织结构稳定性、抗热震性以及失效机制.结果表明,CLZ涂层具有良好的长期组织结构稳定性,涂层在1150℃下热震循环寿命达到26次.涂层失效主要以层状撕裂为主.陶瓷层和粘结层热膨胀不匹配、粘结层发生氧化可能是导致CLZ涂层热震失效的主要原因. 相似文献
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《热喷涂技术》2016,(3)
低压等离子喷涂纳米氧化锆热障涂层,具有独特的组织结构。纳米团聚颗粒在高温等离子射流中部分熔化后沉积到基体上,团聚颗粒能够保留部分纳米结构,形成一种以纳米晶为主的纳米-微米二元结构涂层,为热障涂层的制备提供了一种新的技术方案。YSZ涂层高温服役中,纳米晶粒容易烧结长大。本文通过向YSZ粉体中加入少量的纳米α-Al_2O_3,探讨其抑制YSZ热生长的机制。首先制备了YSZ-Al_2O_3纳米混合物团聚粉末,并借助低压等离子喷涂技术制备涂层。结果表明纳米晶区占主导地位,纳米晶区嵌有少量的微米晶粒。涂层经1400℃,10h热处理,微观组织结构分析表明,α-Al_2O_3的加入对YSZ晶粒热生长具有部分抑制作用。 相似文献
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采用等离子喷涂制备了铈锆酸镧涂层,采用扫描电子显微镜(SEM)、X射线衍射分析(XRD)、图像分析法等研究了喷涂功率对沉积态涂层表面和截面微观结构、孔隙率等的影响规律,研究了涂层在1200℃、1300℃高温100h时效下相稳定性、微观结构、孔隙率的变化,比较了不同喷涂功率涂层的抗热震性能。研究结果表明:随着等离子喷涂功率的增加,喷涂过程中半熔融颗粒比例减小,涂层的孔隙率减小。涂层经1200℃、1300℃高温保温100 h后仍然具有单一的烧绿石结构,随着热处理温度升高,涂层孔隙率减小。研究了不同功率喷涂的涂层从1250℃到冷水中的热震行为,失效机制分析表明:陶瓷层与粘结层热应力不匹配造成陶瓷层底部产生裂纹是导致涂层失效的主要方式。 相似文献
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采用超音速等离子喷涂和普通大气等离子喷涂制备了微米级氧化钇稳定氧化锆(yttria-stabilized zirconia,YSZ)基热障涂层,使用SprayWatch-2i系统测试喷涂过程中粒子飞行速度及表面温度,通过扫描电镜和图像分析技术表征涂层微观结构,利用压痕法测试了断裂韧性和弹性模量,采用基于分形思想的面积-周长幂率定量表征两种工艺条件下孔隙不规则形态,并研究了分形维数对涂层断裂韧性的影响。结果表明:超音速等离子喷涂和普通大气等离子喷涂YSZ涂层孔隙都具有分形特性;超音速等离子喷涂YSZ涂层分形维数是普通等离子喷涂涂层的1.12倍,孔隙结构更复杂,涂层断裂韧性更高。 相似文献
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采用喷雾干燥法制备了一种球形氧化钛团聚粉末, 并通过高温烧结及感应等离子球化工艺对团聚粉末进行
致密化处理。 利用扫描电子显微镜 (SEM)、 霍尔流速计和粉末颗粒强度仪对粉末性能进行了表征, 研究了不同致
密化处理工艺对粉末颗粒强度、 松装密度及流动性的影响。 采用大气等离子喷涂 (APS) 工艺制备了氧化钛涂层,
并对涂层的微观组织进行研究。 研究结果表明, 高温烧结工艺及等离子球化工艺均可有效提升氧化钛团聚粉末
的致密度, 经过高温烧结工艺后氧化钛粉末内部的细小颗粒呈现烧结熔融的趋势, 而采用等离子球化处理后的
团聚粉末直接形成了致密球体结构。 相比于高温烧结工艺, 等离子球化工艺对氧化钛粉末的致密化效应更为明
显, 粉末的颗粒强度可达 187.86 MPa, 松装密度可由 0.79 g/cm3 提升至 1.69 g/cm3, 流动性由 163.22 s/50g 加快
至 100.27 s/50g。 该粉末经过大气等离子喷涂沉积形成的氧化钛涂层孔隙率为 2.8 %, 与未经致密化工艺处理的氧
化钛团聚粉末相比, 制备的涂层致密化水平有了较大程度的提升, 涂层的平均显微硬度值由 434.18 HV0.3 提升至
744.37 HV0.3, 涂层的结合强度均值由 11.07 MPa 提升至 29.93 MPa。 相似文献
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纳米材料由于具有一些独特的效果而表现出了独特的性能,纳米结构稀土硅酸盐被认为是很有前景的环境
障碍涂层 ( EBC ) 材料之一。稀土硅酸盐材料中Yb2SiO5 因其卓越的高温相稳定性、对水蒸气环境的耐久性、低
热导率以及优秀的化学稳定性受到了研究者们的广泛关注。本文研究了大气等离子喷涂工艺 ( APS ) 参数对纳米
结构和传统Yb2SiO5 涂层微观结构的影响,并研究了相同大气等离子喷涂工艺下,纳米结构Yb2SiO5 喂料和传统
Yb2SiO5 喂料对涂层微观结构的影响,分析了APS 制备过程中不同结构喂料对涂层结构影响机制。结果表明:相
同喷涂参数制备的纳米结构Yb2SiO5 涂层孔隙率低于传统Yb2SiO5 涂层,以及纳米结构Yb2SiO5 涂层的铺展性和
融化度均优于传统Yb2SiO5 涂层,表明纳米结构Yb2SiO5 涂层为很有前途的环境障碍涂层之一。 相似文献
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Jeehoon Ahn Byoungchul Hwang Eun Pil Song Sunghak Lee Nack J. Kim 《Metallurgical and Materials Transactions A》2006,37(6):1851-1861
Correlation of microstructure and wear resistance of Al2O3-TiO2 coatings plasma sprayed with nanopowders was investigated in this study. Four kinds of nanostructured Al2O3-13 wt pct TiO2 coatings were fabricated by varying plasma-spraying parameters and were compared with an Al2O3-13 wt pct TiO2 coating fabricated with conventional powders. The nanostructured coatings showed a bimodal microstructure composed of fully
melted regions of γ-Al2O3 and partially melted regions, while the conventional coating mostly consisted of fully melted γ-Al2O3, together with some TiO2-rich regions and unmelted Al2O3 powders. The wear test results revealed that the wear resistance of the nanostructured coatings was 3 or 4 times better than
that of the conventional coating, because the preferential delamination seriously occurred along TiO2-rich regions in the conventional coating. In the nanostructured coatings, TiO2 was homogeneously dispersed inside splats and around, thereby leading to higher splat bonding strength and to better wear
resistance over the conventional coating. 相似文献
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随着纳米科学技术的快速发展,纳米材料被成功地应用到热喷涂领域。研究表明,热喷涂纳米陶瓷涂层比传统陶瓷涂层具有更高的结合强度、韧性、热震性能、耐磨抗蚀性能和可加工性。这种热喷涂纳米陶瓷涂层是利用纳米粉末为原料经过特殊的再造粒过程得到可喷涂喂料,然后方可制备出纳米结构陶瓷涂层。与传统微米结构陶瓷涂层相比,该纳米陶瓷涂层的韧性、结合强度、抗热震性能高1~2倍,耐磨性能高4~8倍,抗疲劳性能提高10倍。发展这样的国际领先的先进表面工程新材料技术,对推动我省的科技和产业发展无疑有重大的战略和经济意义。可以促进我省传统产业的结构调整和产品的升级换代,可以提高我省产品的市场竞争力和我省企业的活力和经济效益。 相似文献
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Vinay Pratap Singh Anjan Sil R. Jayaganthan 《Transactions of the Indian Institute of Metals》2012,65(1):1-12
An ever increasing demand for high-performance ceramic coatings has made it inevitable for developing techniques with precise
control over the process parameters to enable the fabrication of coatings with the desired microstructure and improved structural
properties. The literature on plasma sprayed nanostructured ceramic coatings such as of Al2O3, Cr2O3, and their composites obtained using reconstituted nano sized ceramic powders has been reviewed in this study. Ceramic coatings
due to their enhanced properties are on the verge of replacing conventional ceramic coatings used for various applications
like automotive systems, boiler components, power generation equipment, chemical process equipment, aircraft engines, pulp
and paper processing equipment, land-based and marine engine components, turbine blades etc. In such cases, the advantage
is greater longevity and reliability for realizing the improved performance of ceramic coatings. It has been observed that
the plasma sprayed nanostructured ceramic coatings show improvement in resistance to wear, erosion, corrosion, and mechanical
properties as compared to their conventional counterparts. This article reviews various aspects concerning the plasma sprayed
ceramic coatings such as (i) the present understanding of formation of plasma-spray coatings and factors affecting them, (ii)
wear performance of nanostructured Al2O3, Cr2O3 and their composite ceramic coatings in comparison to their conventional counterparts, and (iii) mechanisms of wear observed
for these coatings under various conditions of testing. 相似文献
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等离子喷涂热障涂层技术广泛应用于航空发动机热端部件的高温防护。应用大气等离子喷涂法成功制备了纳米氧化铈氧化钇稳定的氧化锆(CYSZ)涂层,并与常规氧化钇稳定氧化锆(YSZ)涂层在1300℃下热处理10小时,研究高温对两种涂层性能的影响,与常规的YSZ涂层相比,CeO2的掺杂使涂层具有更高的稳定性。经过高温处理,CYSZ涂层的相结构没有发生明显变化。显微形貌结果表明,CYSZ涂层没有产生裂纹缺陷,涂层中纳米区域晶粒度随着温度的升高略有增大,这表明了纳米结构的CYSZ涂层具有更优异的高温稳定性。热循环氧化实验结果证明,CYSZ涂层具有更长的热循环寿命以及优异的高温抗氧化性能。 相似文献
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Mohammadreza Daroonparvar Muhamad Azizi Mat Yajid Noordin Mohd Yusof Hamid Reza BakhsheshiRad Esah Hamzah Mohsen Nazoktabar 《中国稀土学报(英文版)》2014,32(10):989-1002
Phase transformation of tetragonal ZrO2 to monoclinic phase and also increment of bond coat oxidation kinetic(TGO thickening) can substantially restrict the life time of thermal barrier coating systems(TBCs). So, nanostructured and conventional Y2O3 stabilized ZrO2 coatings were evaluated in fused V2O5-Na2SO4 salts during thermal exposure in air. Microstructural characterization showed lower hot corrosion products(monoclinic zirconia, YVO4 crystals) formation and reduction of TGO thickness in thermal barrier coating system consisting of nanostructured Y2O3 stabilized ZrO2(YSZ) top coat. It was found that inhomogeneities, pores and micro-cracks played a principal role in the molten salts infiltration into the YSZ coating during three steps of hot corrosion process. In the nanostructured YSZ coating with tri-model structure, nano zones which surrounded by fully molten parts could fill the aforementioned defects and could act as barrier for the oxygen and corrosive molten salts penetration into the TBC. 相似文献
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B. Thiyagarajan V. Senthilkumar S. Suresh 《Transactions of the Indian Institute of Metals》2017,70(10):2555-2561
The nickel based as-atomized thermal spray feedstock powder (NiCrFeSiB) was ball milled to produce the nanostructured powder. The feedstock powder was mechanically milled using two station planetary ball-mill. The milled and unmilled feedstock powders were coated using High-velocity oxygen fuel system to produce nanostructured and conventional coatings respectively on the carbon steel substrate (SA210 Grade C). The metallurgical characterization of feedstock powders and coatings were performed using scanning electron microscope, High resolution- transmission electron microscope coupled with energy dispersive spectroscopy and X-ray diffraction techniques. The developed coatings were mechanically characterized by microhardness test and bond strength measurement techniques. The porosity of the coating was measured by analyzing the optical microscope image using the image-J software. In this study, nanostructured coatings exhibited higher hardness, less porous and better bond strength compared to conventional coating. 相似文献
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超音速等离子喷涂纳米防污陶瓷涂层研究 总被引:1,自引:0,他引:1
以NiCr合金为底层,含防污成分的纳米Al_2O_3-13%TiO_2为面层,采用超音速等离子喷涂方法制备纳米防污陶瓷涂层。研究了不同工艺对涂层截面形貌、孔隙率、显微硬度及结合强度的影响,探讨了涂层的防污性能,获得了较优的喷涂工艺参数:Ar流量3.6~3.8 m~3/h,H_2流量0.4 m~3/h,电流400~420A,电压150V,喷距100mm,送粉量30g/min。采用较优超音速等离子喷涂工艺制备的纳米防污陶瓷涂层孔隙率可达0.8%,HV_(0.3)≥987,结合强度≥35.15 MPa,并且抗海生物附着性能优良。 相似文献
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Jianhong He Michael Ice Enrique J. Lavernia 《Metallurgical and Materials Transactions A》2000,31(2):555-564
On the basis of the nanocrystalline Cr3C2-25 (Ni20Cr) feedstock powders produced by mechanical milling, a nanostructured coating has been synthesized using high velocity
oxygen fuel (HVOF) thermal spraying. The properties of the nanostructured coating were compared to those of the conventional
coating of the same composition using scanning electron microscope (SEM), transmission electron microscope (TEM), and microhardness
tests. The nanostructured Cr3C2-25 (Ni20Cr) coating synthesized in this study had an average carbide particle size of 24 nm. Discontinuous elongated amorphous
phases were observed in the nanostructured coating. The conventional Cr3C2-25 (Ni20Cr) coatings produced using blended elemental powders exhibited an inhomogeneous microstructure. The observed homogeneity
of the nanostructured coating is attributed, in part, to the microstructural improvement of the starting powder. The nanostructured
Cr3C2-25 (Ni20Cr) coating yielded an average microhardness value of 1020 DPH300, which corresponds to a 20 pct increase in microhardness over that of the conventional coating. The nanostructured Cr3C2-25 (Ni20Cr) coating also exhibited a higher apparent fracture toughness relative to that of the conventional coating. The
apparent mechanical property improvements in the nanostructured coating were thought to result from the uniformity of the
microstructure and the high performance associated with a nanostructured structure. In addition, the mechanism that is present
during the milling of a system containing nondeformable particles is discussed in light of the TEM observations. 相似文献
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Nanostructured yttria partially stabilized zirconia(YSZ) coatings were prepared by atmospheric plasma spraying(APS) using the conglomeration made by zirconia nanoparticle as the raw materials.The measurement methods,which consisted of scanning electron microscopy(SEM),transmission electron microscopy(TEM) and thermal cycling behavior,were used to character the morphology,composition and thermal oxidation behavior of the powder and the coatings.From the results,it was shown that the YSZ coating was the laminar structure,and the elements distribution in the bond and top coat were well-proportioned.The YSZ coatings were composed of fine grains with size ranging from 30 to 110 nm.The laminar layers with columnar grains were surrounded with unmelted parts of the nanostructured powder and some equiaxed grains.In the as-sprayed nanostructured zirconia coatings,there existed pores that were less than 1 μm.The cracks were observed on some of the crystal border.The cyclic oxidation experiment showed that the nanostructured coating had longer thermal cycling lifetime to exhibit the promising thermal cyclic oxidation resistance.The failure of the nanostructured TBC was similar to the failure of conventional APS TBC. 相似文献