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发现于20世纪60年代的铝基非晶合金作为一种低密度材料拥有着较高的比强度,而且与传统晶态材料相比,呈现出长程无序、短程有序的原子排列特点,其内部不存在晶界、位错等较易引发失效的缺陷结构,表现出高硬度和优异的防腐、耐磨等性能,受到了国内外众多学者的广泛关注.起初,这类材料由于受到制备工艺的限制,表现为非晶与纳米晶共存的结构.随着科技发展,科学家们开发了一系列具有完全非晶结构的铝基合金体系.这些材料在具有较高的机械强度的同时能够表现出良好的韧性,使人们对其非晶形成能力、制备方法及应用推广等方面产生了较大的兴趣.对铝基非晶合金非晶形成能力的研究,学者们通常基于块体非晶合金非晶形成能力的经验判据,以及其他一些新提出的判定方法,如蒸发焓、费米层电子态密度、原子扩散以及析出相熔点等.但是,由于铝基非晶合金过冷液相区间较窄以及Al元素化学活性较强,因此铝基非晶合金的非晶形成能力普遍较弱.虽然人们在元素种类及含量变化对铝基非晶合金非晶形成能力的影响等方面做了大量的研究工作,但是目前仍未形成具有普适性的或更加精确的铝基非晶形成能力判定方法,未来仍需借助高性能材料模拟计算和机器学习等技术来进行完善.铝基非晶合金非晶形成能力较弱,以及其对外界条件的影响较为敏感,导致其在制备过程中易发生晶化,从而使获得的材料尺寸维度普遍较低.目前,铝基非晶合金的常见制备方法可按照其形态(粉状、块体、涂层等)来进行划分.粉状铝基非晶合金的制备方法主要为气雾化法和机械合金化法;块体铝基非晶合金的制备方法主要为直接凝固法和粉末冶金法;涂层类铝基非晶合金的制备方法主要包括激光熔覆、爆炸喷涂、冷喷涂、超音速火焰喷涂和电弧喷涂.相对而言,铝基非晶涂层制备技术不会受到工件尺寸的限制,工艺简单、操作方便,且适合于户外大面积施工,在表面防护与再制造工程领域更具应用潜力.尤其是在大型舰船、飞机、海洋设施等高附加值零件的再制造领域里,铝基非晶涂层制备技术的大规模推广应用将会带来巨大的经济效益.本文介绍了铝基非晶合金的发展过程、非晶形成能力、制备方法等内容,总结了铝基非晶涂层在再制造领域的应用前景,并展望了铝基非晶合金的未来研究方向. 相似文献
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非晶合金的短程有序,长程无序和不存在晶界、位错等晶体缺陷等特点,使其具有较高的强度以及优异的防腐耐磨性能,从而成为一种具有广阔应用前景的新型金属材料。 然而,由于非晶合金体系本身非晶形成能力和制备技术的限制,目前难以得到具有工程意义的大尺寸块体结构材料。为了充分利用其优异的性能和扩大其应用领域,众多学者对制备非晶合金涂层展开了广泛研究。以超音速火焰喷涂为代表的热喷涂技术由于具有加工工艺简单、热输入低、喷涂材料范围大、制备的涂层耐磨耐蚀性能好等优势成为了制备非晶合金的重要方式。目前,利用超音速火焰喷涂技术制备的非晶合金涂层主要有Fe基、Ni基和Mo基等。而在众多的非晶体系中,Fe基非晶合金涂层由于其优异的性能和低廉的成本受到了广泛关注。研究者们发现,制备性能优异的Fe基非晶合金涂层不仅需要合适的制备方法,同时合金系成分的合理选择以及制备过程中工艺参数的优化能够完善非晶合金本身的优良特性,保证非晶合金具有更好的非晶形成能力并提高涂层的质量及使用性能。 目前,通过超音速火焰喷涂的涂层孔隙度通常低于2%,在使用改进型空气超音速火焰喷涂系统后可以将涂层的孔隙度降低到0.3%以内,使得涂层更致密,减少涂层浸泡在腐蚀介质中由于孔隙造成的涂层破坏,延长涂层的使用寿命。另外,在深共晶规律、电子密度规律、热力学规律等经验规律的指导下,研究者们开发了很多成分多元的Fe基合金体系,使得制备的非晶合金涂层在耐磨耐蚀等性能上都有很大提升,例如七元合金体系中的Fe40Cu8Cr15Mo14C15B6Y2在干摩擦磨损实验中,磨损量仅为相同条件下45号钢的四分之一,说明其具有优异的耐磨性能;八元合金体系中的Fe63Cr8Mo3.5Ni5P10B4C4Si2.5在进行3.5%(质量分数)NaCl溶液的电化学腐蚀实验后,比相同条件下304不锈钢涂层表面的腐蚀坑更少、更小,拥有更好的抗腐蚀性能。 本文对超音速火焰喷涂Fe基非晶合金的研究现状进行了综述,归纳总结了合金化学成分和喷涂参数对Fe基非晶合金涂层摩擦学性能和耐蚀性能的影响。并对超音速火焰喷涂制备性能优异的Fe基非晶合金涂层的研究前景进行了展望。 相似文献
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为解决非晶粉末价格昂贵、成型困难等问题,采用真空气雾化法制备了Ni FeCrMoNbBSi合金粉末,利用火焰喷涂焰流温度高、冷凝速度快有利于形成非晶相等特点,经火焰喷涂后制备了镍基非晶涂层。通过XRD、SEM、EDS、TEM等对粉末和涂层的相组织结构、表面形貌和微观特征进行了表征。结果表明:Ni FeCrMoNbBSi合金粉末形貌为球形或近球形,主要由晶体相FeNi3和Ni CrFe固溶体组成,非晶含量较少。制备的Ni基非晶涂层组织结构致密,主要由非晶相和Cr2Ni3金属间化合物组成,非晶含量可达70%(体积分数)。 相似文献
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非晶合金粉末是指快冷雾化合金液滴所制得的合金粉末,其中Fe基非晶合金粉末因具有生产成本低廉和应用前景广阔等优势,一直备受青睐。同时,Fe基非晶合金粉末的应用也为块体Fe基非晶合金应用难的问题提供了一条崭新的途径。本文综述了Fe基非晶合金粉末的研究进展,对其在涂层制备、磁性材料、激光3D打印、废水处理4个方面的研究现状进行了归纳分类与总结,并分析了Fe基非晶合金粉末在各领域的应用优势。最后指出Fe基非晶合金粉末在制备高质量涂层、老化磁性粉末再利用及增材制造领域的研究方向,并展望了作为传感、控制等功能性器件的应用前景。此外,在薄膜等小尺寸、低维材料及柔性电子领域也展现出巨大的应用潜力。 相似文献
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非晶合金的结构特点是短程有序,长程无序,不存在晶界和位错等晶体缺陷.Fe基块体非晶合金尽管具有超高的硬度和强度、出色的耐腐蚀和耐磨性,且成本低廉,但是也因非晶形成能力低及室温脆性而大部分以粉末、薄带、毫米棒等形式存在,使其推广和应用受到较大限制.将非晶合金制备成涂层,不仅能有效弥补上述不足,还保留了块体非晶合金固有的特性,已在石油化工、汽车机械、海洋工程等制造和再制造领域获得应用.超音速火焰喷涂(HVOF)、等离子喷涂(APS)等技术已被证实能够在钢材基体上制备Fe基非晶涂层.根据诸多研究结果可知,影响Fe基非晶涂层耐腐蚀性能的因素主要有:非晶成分(如Cr、Mo、Ni、Nb等元素)、孔隙率、晶化相、粉末粒径、氧化物、喷涂工艺及参数、外界环境等.同时,研究者们还在提高喷涂非晶涂层耐腐蚀性的工艺措施方面取得了一些成果,包括热处理、封孔处理、激光重熔、氧化处理、离子注入、极化处理等.这些努力极大地推动了Fe基非晶涂层在海洋装备腐蚀防护中的实际应用.本文总结了Fe基非晶涂层耐腐蚀性能的影响因素和提升措施方面的相关研究进展,并简要分析了研究中存在的不足以及未来发展前景. 相似文献
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Kobayashi A Kuroda T Kimura H Inoue A 《Journal of nanoscience and nanotechnology》2012,12(6):4883-4886
Metallic glass is one of the most attractive advanced materials, and many researchers have conducted various developmental research works. Metallic glass is expected to be used as a functional material because of its excellent physical and chemical functions such as high strength and high corrosion resistance. However, the application for small size parts has been carried out only in some industrial fields. In order to widen the industrial application fields, a composite material is preferred for the cost performance. In the coating processes of metallic glass with the conventional deposition techniques, there is a difficulty to form thick coatings due to their low deposition rate. Thermal spraying method is one of the potential candidates to produce metallic glass composites. Metallic glass coatings can be applied to the longer parts and therefore the application field can be widened. The gas tunnel plasma spraying is one of the most important technologies for high quality ceramic coating and synthesizing functional materials. As the gas tunnel type plasma jet is superior to the properties of other conventional type plasma jets, this plasma has great possibilities for various applications in thermal processing. In this study, the gas tunnel type plasma spraying was used to form the metallic glass coatings on the stainless-steel substrate. The microstructure and surface morphology of the metallic glass coatings were examined using Fe-based metallic glass powder and Zr-based metallic glass powder as coating material. For the mechanical properties the Vickers hardness was measured on the cross section of both the coatings and the difference between the powders was compared. 相似文献
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Aluminium foams produced via the PM‐process are characterized by a moderate specific strength, a high surface roughness, and a poor wear behavior; to increase their mechanical properties and to improve the surface finish, wear and corrosion resistance; thermally sprayed coatings can be applied. The quality of the coating depends on the coating material, the chosen process, the preparation of the surface and spraying parameters. Aluminium alloys and iron based alloys for abrasive applications were deposited via electric arc spraying, ceramic coatings against wear were deposited by means of plasma spraying. Hard metallic coatings for severe abrasive applications were applied by high‐velocity‐oxyfuel spraying (HVOF). The results proved the suitability of this technique to significantly enhance the mechanical properties and the surface finish of metal foams. The specific strength and stiffness of the new composite materials outperform pure metal foams. The corrosion behavior was tested performing a salt spray test. 相似文献
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This investigation was conducted to clarify the effects of process parameters on the formation of the new amorphous coating using a Zr-based alloy, which is known as bulk metallic glass forming alloy, by a HVOF (High Velocity Oxygen Fuel) spraying process. Powders used for spraying was prepared by vacuum gas atomization and then crushed by a centrifugal mill. HVOF spraying experiments were carried out using a Tafa JP-5000 spraying gun. DTA (Differential Thermal Analysis) measurements have shown that the amorphous content of the coatings was measured up to about 62% depending on the spraying process parameters. The amorphous fraction of the coatings is decreased with increasing the spray distance and the fuel flow rate. Microstructural observations and X-ray diffraction analysis of the spray coated layers reveal that the amorphization behavior during the spraying is attributed to the degree of the solidification of droplets and the oxide (ZrO2) formation in spray coated layers. Therefore, flame temperature and spray distance that can control the carrier gas temperature and undercooling effects of the droplets are the most crucial factors for the evolution of the amorphous phase using this bulk metallic glass forming alloy. 相似文献
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Pure aluminium coatings were prepared on magnesium-zinc-yttrium-calcium alloy substrate via cold spraying technology with different scanning speeds and working gas temperature. The correlation between the corrosion resistance of the coatings and the different spraying process was studied. While the working gas temperature is 600 °C and the scanning speed is 1 mm/s, aluminium coating has less porosity and the coating was well combined with the substrate. Higher temperature of working gas increases the plastic deformation of particles, which lead to a dense aluminium coating. The relationship of corrosion resistance on working gas temperature and scanning speed of aluminium coatings has also been investigated by immersion corrosion test and electrochemical impedance spectroscopic techniques. The results show that the cold sprayed aluminium coatings revealed a lower porosity and higher corrosion resistance with the decreasing scanning speed and the increasing temperature of working gas. The porosity and corrosion current densities were 0.938 vol.% and 2.427 ⋅ 10−6 A/cm2. The experimental results show that the aluminium coating prepared by cold spraying has a good protective effect on magnesium alloy. 相似文献
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Hard transparent corrosion-resistant dielectric coatings were investigated (a) for application to the direct protection of glass surfaces, (b) for application to the protection of thin film metallic window coatings used for reflection or transmission of solar radiation and (c) for use in codeposited metal-ceramic coatings. The dielectric coatings were Al2O3, SiO2 and SiC in the thickness range 100–100 000 Å. The coatings were deposited under varying conditions of substrate temperature, gas composition, r.f. power and substrate preparation. The results of the following measurements on the dielectric coatings are presented: diamond pyramid hardness tests, optical reflectance and transmittance in the region 0.6–4.0 eV and corrosion resistance tests under cyclic conditions. The results showed a considerable improvement in the scratch resistance and hardness of glass by layering of hard dielectric coatings 2–5 μm thick. 相似文献
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Cold spraying (CS), a solid-state spraying technology, is expected to become an appropriate supplementary for traditional spraying methods owing to its plenty of merits such as high deposition efficiency, low temperature and little influence on the particles/substrate. The most reported researches are bulk alloys fabricated by CS. However, the systematic introduction and cold-sprayed metallic glass coatings have not been summarised. Therefore, in this paper, the international research status of CS including equipment structure, spraying process and parameters, advantages and disadvantages, deposit features and bonding mechanism were introduced. By using this technology, the successful researches about Fe-, Al-, Ni-, Cu- and Zr- based amorphous alloy coatings are reported. To overcome the limitations, further development and solutions were proposed. 相似文献