第一讲装备再制造技术（十）

涂层的耐磨性表15～表17列出了低碳马氏体（LM）、3Crl3、1Cr18Ni9T三种材料电弧喷涂层的磨损量和相对耐磨性（丝材直径为Ф2mm）。可以看出，材料和喷涂工艺相同的条件下，高速电弧喷涂层的耐磨性比普通电弧喷涂层提高一倍以上。在润滑条件下，     

HVAF-ARC喷涂Cr2C3活性功能涂层性能的研究

本文采用HYAF-ARC喷涂系统制造的NiCrFe-Cr2C3活性功能涂层。通过金相组织研究、SEM检测．X射线衍射以及涂层结合强度分析．证明其具有良好的组织形貌;同时HVAF-ARC所制备的Cr2C3合金除层的性能相对于普通电弧喷涂涂层的性能在同等试验条件下优于普通高速电弧喷涂。     

喷砂预处理工艺对涂层结合强度的影响

近年来,高速电弧喷涂以其优异的性能得到广泛的应用。为提升其喷涂涂层与基体的结合强度,研究人员主要专注于新的喷涂材料的研究。文中分析高速电弧喷涂操作工艺并提出,改进喷涂预处理工艺,同样对提升涂层与基体的结合强度有较大的影响,并通过试验,得到了优化的预处理工艺参数。     

高速电弧喷涂技术简介

一、电弧喷涂原理 电弧喷涂是以电弧为热原，将熔化的金属丝用高速气流雾化，并以高速喷射到工作表面形成涂层的一种工艺。高速电弧喷涂技术，是在电弧喷涂的基础上发展起来的一种新型电流喷涂技术。广泛应用防腐、耐磨、特种功能等。不失为一种表面强化最有效，最经济的技术。二、电弧喷涂技术的特点 １．电弧喷涂的优点突出表现在其涂层高的结合强度和优导的涂层性能。２．电弧喷涂的生产效率高。３．电弧喷涂的节能效果十分突出，能原利用率显著高于其它喷涂方法（电弧喷涂时原利用率达５７％，火焰喷涂达 １３％等离子喷涂达 １２％）。…     

电弧喷涂制备高硬度、耐磨、抗氧化涂层及其性能研究

腐蚀和磨损是材料破坏的主要形式。在高温工况下，不仅要求涂层具有较高的耐磨性，还要有一定的抗高温氧化性能。采用电弧喷涂的技术制备了1种高硬度、耐磨、抗氧化涂层，测试涂层的硬度、结合强度、磨粒磨损、气孔率以及微观组织结构，并进行了分析讨论。     

高速电弧喷涂枪的设计

高速电弧喷涂枪是实现高速电弧喷涂的关键装置.本文介绍了采用高速气流技术方案研制的高速电弧喷涂枪,在喷枪的设计中优化采用了超音速喷管,使得喷枪出口80mm范围内雾化气流的速度达到600m/s以上,有利于增强喷涂粒子的雾化效果,提高粒子速度,从而使喷涂层的质量和性能明显改善,为高速电弧喷涂技术的工业应用奠定了基础.     

高效能超声速等离子弧喷涂技术研究

近年来高速喷涂已成为国际热喷涂技术的发展趋势，爆炸喷涂、高速火焰喷涂、高速电弧喷涂及超声速等离子弧喷涂等技术越来越受到重视。超声速等离子弧喷涂技术与其他高速喷涂技术相比，具有射流速度高、热源温度高、效率高，可以喷涂几乎所有粉末材料(特别是高熔点陶瓷材料、难熔金属和金属陶瓷等)的综合优点，获得的涂层致密性、强韧性和结合强度都有显著提高。目前国外只有     

铁铝金属间化合物基涂层的高温滑动磨损性能研究

采用粉芯丝材和高速电弧喷涂技术制备了Fe-Al金属间化合物涂层及Fe-Al/WC复合涂层，研究了从室温至650℃不同试验温度下两种涂层的滑动磨损性能。结果表明，在高温下磨损面发生摩擦氧化反应形成大面积的氧化物保护层，降低了涂层的摩擦系数；剥层磨损是涂层的主要磨损机理。涂层中Fe3Al和FeAl金属间化合物相较高的高温强度和硬度，能有效地阻碍裂纹的产生、扩展及扁平颗粒的断裂，从而使Fe-Al涂层及Fe-Al/WC复合涂层表现出优异的高温耐磨性。添加WC硬质相后提高了复合涂层的平均硬度，从而提高了涂层的耐磨性；但高温下WC易发生氧化和分解，使复合涂层的高温耐磨性下降。     

电弧喷涂马氏体不锈钢涂层的应用

目前,随着电弧喷涂设备的不断改进,电弧喷涂工艺以其生产成本低、喷涂效率高、涂层性能可靠等显著特点,越来越受到人们的重视。电弧喷涂使用的材料非常广泛,可加工成丝材的金属或合金都可以使用。 在电弧喷涂过程中,电弧使马氏体不锈钢线材熔化,熔滴经压缩空气雾化,沉积在工件表面上,在极短时间内完成凝固扇和马氏体相变过程,得到的涂层具有较高的硬度、耐磨性和耐蚀性。这种涂层用于修复     

DS-200型电弧丝喷涂设备

一、电弧丝喷涂技术简介电弧丝喷涂由于具有操作简单、成本低、设备灵活机动、涂层质量好等优点,越来越引起人们的重视。电弧丝喷涂的工作原理是在加有直流电压,并以一定角度不断连续送进的两根金属丝的端点产生电弧。电弧区域中的金属丝被熔化,同时被高速压缩空气流雾化,以高速喷射到被喷涂表面形成涂层。电弧丝喷涂具有如下特点:     

Abrasive wear behavior of sprayed hydroxyapitite coatings by gas tunnel type plasma spraying

Hydroxyapatite (HA) coatings were sprayed using gas tunnel type plasma spraying at different arc currents. Abrasive wear test was carried out for the coatings sprayed at different arc currents under unlubricated conditions in air atmosphere. The abrasive wear rate was measured at different coatings thickness to study the effect of coating thickness on the anti-abrasion resistance of HA coatings. The results showed that the abrasive wear resistance of HA coatings increases as the operating arc current of the plasma torch increases. On the other hand, the abrasive wear rate reaches a minimum value near the substrate with coating thickness less than 50 μm. The results showed that the coating hardness increases in the region near the substrate and increases as the arc current increases. The experimental results indicated that there is a relation between the abrasion resistance and hardness properties of HA coatings.     

高速电弧喷涂粒子速度和雾化特性研究

对比研究了高速电弧喷涂和普通电弧喷涂ＡＩ和３Ｃｒ１３的粒子速度和雾化特性,用Ｐｉｔｏｔ管总压法。双转盘法和扫描电镜、图象分析仪分别测定了喷枪出口雾化气流速度和粒子速度的轴向分布,以及不同工艺条件下雾化粒子的粒度分布。用ＰｅａｒｓｏｎＸ２分布拟合检验法对粒子的粒度分布进行统计分布检验。结果表明,高速电弧喷涂ＡＩ和３Ｃｒ１３粒子的平均飞行速度为３４２ｍ／ｓ和３８８ｍ／ｓ;雾化粒子平均粒度分别为普通电弧喷涂的１／３和１／８;雾化气流轴向速度在主要雾化区间（ｄ＜１００ｍｍ）为７００－５５０ｍ／ｓ;高速电弧喷涂和普通电弧喷涂川粒子的粒度具有相同的分布规律,而高速电弧喷涂３Ｃｒ１３粒子的粒度却具有不同的分布规律。探讨了高速电弧喷涂雾化机理和影响粒子速度的因素。     

增强相对高速电弧喷涂铁铝复合涂层摩擦学特性的影响

使用铁铝粉芯喷涂丝材，结合高速电弧喷涂技术在锅炉钢上得到了铁铝复合涂层，分析了涂层的成分和相组成，对涂层进行了摩擦磨损试验，并在扫描电镜上观察了磨斑的形貌和成分。结果表明：添加增强相可以提高涂层的力学性能；添加了Cr3C2增强相的铁铝复合涂层具有优良的常温耐磨损性能；而添加铬和镍元素则可以略微增加涂层的耐磨损性能；添加增强相WC和Cr3C2的涂层在高温的情况下出现了摩擦因数降低的趋势。     

Evaluation of unlubricated wear properties of plasma-sprayed nanostructured and conventional zirconia coatings by SRV tester

Atmospheric plasma spraying method was used to deposit nanostructured and conventional zirconia coatings using spray-dried nanostructured zirconia powder and conventional zirconia powder as feedstock, respectively. Their wear properties were evaluated comparatively by a sliding, reciprocating and vibrating (SRV) tester under dry conditions. The obtained results show that the wear properties of the plasma sprayed zirconia coatings deposited from spray-dried nanostructured zirconia powder were greatly improved compared with those of plasma sprayed zirconia coatings produced from conventional powder. The wear rates of nanostructured zirconia coatings are approximately half of those of conventional zirconia coatings. Under dry conditions, the wear mechanism for the plasma-sprayed nanostructured zirconia coatings is abrasive wear. Whilst in the case of plasma sprayed conventional zirconia coatings, it is a combination of abrasive wear and brittle fracture, the former is dominant wear mechanism. Their wear properties were explained in terms of their microstructure as well as mechanical properties and compared with the wear properties obtained under distilled-water lubricated conditions. Based on the experimental results, it is concluded that the finer debris is a critical factor for the improvement of wear properties of plasma-sprayed nanostructured zirconia coating under dry conditions. The wear properties of plasma sprayed zirconia coatings can be increased by the presence of water during the SRV testing.     

TiB2陶瓷颗粒增强电弧喷涂涂层滑动磨损性能的研究

采用电弧喷涂含TiB2陶瓷粉末的粉芯丝材,在低碳钢基体上制备了NiCr-TiB2和304L-TiB2金属基复合涂层,在摩擦磨损试验机上研究了按环/块线接触方式作往复运动条件下无润滑时室温下的摩擦磨损性能,利用光学显微镜、扫描电子显微镜和X射线衍射仪对涂层的显微组织结构、磨损表面及其相组成进行分析。结果表明,涂层的相对耐磨性能远高于碳钢基体,约为9到11.5倍。304L-TiB2涂层的低磨损率除了与硬质相有关,还和涂层具有较高的硬度有关。NiCr-TiB2涂层的耐磨性能好,细小的TiB2陶瓷相在局部涂层中连成网状,与基体结合良好,有效提高了涂层的磨损性能。     

Improvement in wear resistance of plasma sprayed yttria stabilized zirconia coating using nanostructured powder

Plasma sprayed yttria stabilized zirconia coatings were prepared using nanostructured and conventional powders with optimized process parameters for the highest deposition efficiency, the smallest porosity and the highest microhardness. The tribological properties of these coatings against 100C6 steel were then tested with a ball-on-disc arrangement. Results showed that although the friction coefficients of the coatings sprayed using the nanostructured powder were slightly different from those of the coatings sprayed using the conventional powder, the former coatings were more wear resistant than the latter coatings. The wear mechanisms of all the coatings were explained in terms of adhesion-induced spallation and micro-fracturing of lamellae. The improvement in wear resistance of the coatings sprayed using the nanostructured powder could be mainly ascribed to the decrease of micrometer-sized defects such as pores and interlamellar and intralamellar cracks in the coatings.     

高速电弧喷涂3Cr13钢雾化粒子温度和飞行速度数值模拟

用二相流流体动力学和空气动力学理论建立了高速电弧喷涂雾化粒子温度和飞行速度的数学模型,通过引入高速电弧喷涂工艺过程的送丝速度、丝材直径、喷涂电流、电压和雾化气体压力等工艺参数,与雾化微滴温度、飞行速度和粒度分布建立联系,揭示了高速电弧喷涂工艺参数对雾化过程微滴物理特性的影响。数值分析结果表明,3Cr13钢微滴速度在实际喷涂距离范围内变化不大;粒度对微滴初始温度有较大影响;不同粒度微滴的过热度在1 320～2 090 K之间,电阻项对微滴过热度的贡献最大;微滴强烈过热是电弧喷涂材料损耗的主要原因之一。所建立的模型的数值模拟结果与试验结果吻合较好。模拟计算的高速电弧喷涂技术喷涂3Cr13钢的质均粒度和实测的相吻合,但粒度分布特征不同。     

Sliding wear behavior of Fe-Al and Fe-Al/WC coatings prepared by high velocity arc spraying

A comparative study was carried out to investigate the microstructure and tribological behavior of Fe-Al and Fe-Al/WC iron aluminide based coatings against Si₃N₄ under dry sliding at room temperature using a pin-on-disc tribotester. The coatings were prepared by high velocity arc spraying (HVAS) and cored wires. The effect of normal load on friction coefficient and wear rate of the coatings was studied. The microstructure and the worn surfaces of the coatings were analysed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersion spectroscope (EDS). The results showed that, the main phases in both coatings were iron aluminide (Fe₃Al and FeAl) and α. WC/W₂C particles were embedded in the matrix of the composite coating. With adding WC hard particles, the Fe-Al/WC composite coating exhibited higher wear-resistance than Fe-Al coating. But the friction coefficient of both coatings showed little difference. As the load increased, the friction coefficient decreases slightly due to a rise of friction contact temperature and larger areas of oxide film formation on the worn surface, which act as a solid lubricant. Increasing load causes the maximum shear stress occurring at the deeper position below the surface, thereby aggravating the wear. The coating surface is subjected to alternately tensile stress and compression stress during sliding, and the predominant wear mechanism of the coatings appears to be delamination.     

纳米表面工程与摩擦学

利用表面工程技术解决摩擦磨损问题具有高效、实用等特点。随着科学技术的迅速发展，纳米材料和纳米技术在表面工程中得到了广泛应用，由此出现了“纳米表面工程”。利用纳米表面工程技术制备的涂层和镀层有着非常优异的摩擦学性能。本文叙述了作者近年来的有关工作，包括热喷涂纳米陶瓷涂层、热喷涂纳米自润滑涂层、纳米陶瓷／聚合物复合涂层、纳米复合电镀层以及纳米电泳沉积层的摩擦磨损特性和机制。     

Effects of CeO2 on friction and wear characteristics of Fe–Ni–Cr alloy coatings

The effects of rare earth oxide CeO₂ on the microstructure and wear resistance of thermal sprayed Fe–Ni–Cr alloy coatings were investigated. The powders of Fe–Ni–Cr alloy with the addition of CeO₂ were flame sprayed on to a 1045 carbon steel substrate. The coatings were examined and tested for microstructure feature, compositions, and phase structure. Tribological properties of coatings were tested under reciprocating sliding test. The results were compared with those for coatings of the alloy without CeO₂. The comparison indicated that the addition of rare earth oxide CeO₂ could refine and purify the microstructure of coatings, and increase the microhardness of the coatings. As a result, by CeO₂ addition, the friction coefficient of the coatings was decreased slightly and the wear resistance of the coatings was enhanced significantly.