双丝电弧喷涂Ni-Al复合涂层的显微结构与力学性能分析
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"这篇2014年的论文研究了通过双丝电弧喷涂技术在6061-T6铝合金板上制备的Ni-5wt%Al和Ni-20wt%Al复合涂层的微观结构和机械性能。研究在不同实验条件下进行，探讨了耐磨性能等关键特性。"
论文详细内容：
这篇由Ji-xiao Wang等人发表在《国际矿物、冶金与材料》期刊上的研究，深入探讨了双丝电弧喷涂法制备的镍铝合金复合涂层的微观结构和机械性能。6061-T6铝合金因其优异的耐腐蚀性和可加工性，在航空航天、汽车等领域广泛应用，而其表面的强化涂层则能进一步提升这些性能。
研究中，作者采用双丝电弧喷涂技术制备了两种不同铝含量（5wt%和20wt%）的镍铝合金涂层。这种技术利用两根连续送进的金属丝在电弧的作用下熔化并高速喷射到基材表面，形成致密的涂层。通过对不同条件下的实验结果进行对比，分析了涂层的微观结构，包括颗粒形态、组织均匀性以及涂层的结合强度。
实验结果显示，Ni-5wt%Al和Ni-20wt%Al复合涂层的微观结构受到喷涂参数的影响，如喷射速度、电流和气体流量等。较高的铝含量可能导致更大的颗粒，这可能会影响涂层的致密度和耐磨性能。同时，研究还关注了涂层的机械性能，包括硬度、冲击韧性和耐磨性。耐磨性能是评价涂层在实际应用中耐磨损能力的重要指标，尤其对于承受高应力和磨损的工况而言。
通过对涂层进行耐磨测试，研究人员发现，尽管高铝含量的涂层可能具有更高的硬度，但其耐磨性能并不一定优于低铝含量的涂层。这可能是由于颗粒间的结合强度和涂层的内部缺陷对耐磨性有显著影响。此外，论文还讨论了热处理对涂层性能的影响，热处理可以改善涂层的组织，提高其与基材的结合力。
这项研究为优化6061-T6铝合金表面的Ni-Al复合涂层提供了理论基础，有助于设计出更适应特定应用需求的高性能涂层。同时，对于理解和改进双丝电弧喷涂工艺也有重要的指导意义，对于工程技术领域，尤其是材料表面改性，有着深远的实践价值。
International Journal of Minerals, Metallurgy and Materials
Volume 21, Number 5, May 2014, Page 469
DOI: 10.1007/s12613-014-0931-8
Corresponding author: Ji-xiao Wang E-mail: jixiao_wang@163.com
© University of Science and Technology Beijing and Springer-Verlag Berlin Heidelberg 2014
Microstructure and mechanical properties of twin-wire arc sprayed Ni−Al
composite coatings on 6061-T6 aluminum alloy sheet
Ji-xiao Wang
1,2)
, Jing-shun Liu
3)
, Lun-yong Zhang
4)
, Jian-fei Sun
1)
, and Zhi-ping Wang
5)
1 ) School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China
2 ) Harbin Welding Institute, China Academy of Machinery Science & Technology, Harbin 150028, China
3) School of Materials Science and Engineering, Inner Mongolia University of Technology, Hohhot 010051, China
4) National Laboratory of Solid State Microstructures & Department of Materials Science and Engineering, Nanjing University, Nanjing 210093, China
5) College of science, Civil Aviation University of China, Tianjin 300300, China
(Received: 19 November 2013; revised: 10 January 2014; accepted: 20 January 2014)
Abstract: We have systematically studied the microstructure and mechanical properties of Ni−5wt%Al and Ni−20wt%Al composite coat-
ings fabricated on 6061-T6 aluminum alloy sheet by twin-wire arc spraying under different experimental conditions. The abrasive wear be-
havior and interface diffusion behavior of the composite coatings were evaluated by dry/wet rubber wheel abrasive wear tests and heat treat-
ment, respectively. Experimental results indicate that the composite coatings exhibit features of adhesive wear. Besides, the Vickers micro-
hardness of NiAl and Ni
3
Al intermetallic compounds is relatively larger than that of the substrate, which is beneficial for enhancing the wear
resistance. With the increase of annealing temperature and time, the interface diffusion area between the Ni−Al coating and the substrate
gradually expands with the formation of NiAl
3
and Ni
2
Al
3
phases, and is controlled by diffusion of aluminum atoms. The grain growth ex-
ponent n of diffusion kinetics of the Ni−Al coating, calculated via a high-temperature diffusion model at 400, 480, and 550°C, is between
0.28 and 0.38. This satisfies the cubic law, which is consistent with the general theoretical relationship of high-temperature diffusion.
Keywords: composite coatings; intermetallics; spraying; aluminum alloys; mechanical properties; diffusion
1. Introduction
6061-T6 aluminum alloy is a medium to high strength,
heat-treatable alloy that is being extensively used for the
fabrication of deflectors in aircraft carriers [1] and the Ma-
rine Corps AM2 mats [2]. The surface of the Al alloy
6061-T6 used in these applications is often coated with ep-
oxy-based coatings containing hard particles to realize a
nonskid surface and adherence to the aluminum substrate.
Of the different methods used for coating the Al alloy
6061-T6, arc spray coating technology offers the advantages
of low operational cost, high spray rate, and efficiency,
making it an ideal method for spraying large areas. Besides,
the coatings fabricated by the arc spray technology are typi-
cally denser and stronger than those fabricated by combus-
tion spray coatings. Recent advancements in equipment and
processing methodologies have greatly improved the quality
and expanded the potential applications of thermally
sprayed coatings. This method offers the possibility of spray
coating a wide range of metals, alloys, and metal-matrix
composites. The twin-wire arc spraying technique has sev-
eral advantages, including high-temperature and high-ve-
locity deposition, wherein the arc temperature can reach up
to 5000−7000°C, and the particle velocity ranges from 100
to 500 m/s. At such high temperature and velocity, the mol-
ten ends of the wires are dispersed and accelerated by a gas
stream (air or inert gas). The coatings obtained under such a
combination of high arc temperature and particle velocity
have superior bond strength and lower porosity level,
compared with the flame sprayed coatings [3]. Thermally
sprayed nickel-based alloy coatings are being used in a vari-
ety of applications, including bond coats for thermal barrier
coatings (TBCs) on turbine components and internal com-
bustion engine cylinders, corrosion protection of boiler
tubes, and in numerous other applications requiring wear,
high-temperature and corrosion-resistant surfaces.
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