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为了解决铝制发动机缸体耐磨性差这一问题,利用热喷涂技术在铝制发动机气缸内壁制备一层铁基耐磨涂层,就能大大增加缸体的耐磨性。该文选择了两种喷涂丝材和适合的喷涂工艺,在铝制缸体内壁上制备出耐磨涂层,并对涂层的硬度、厚度、微观组织、物质组成及耐磨性进行试验并分析,结果表明利用热喷涂技术制备出的耐磨涂层硬度适中,涂层中存在的大量氧化物和孔隙结构,可以提高涂层材料的耐磨性,在湿摩擦条件下,涂层的摩擦系数均小于灰铸铁的,从而说明在铝制缸体内壁上制备耐磨涂层,是实现汽车的轻量化的一条有效途径。 相似文献
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为了提高电弧喷涂涂层的结合强度及耐磨损性能,采用超音速电弧喷涂技术和普通电弧喷涂技术在Q235钢表面分别制备了Fe17Cr5NiB涂层,通过扫描电镜(SEM)、X射线衍射仪(XRD)、显微硬度计、摩擦磨损试验机等手段对比分析了2种涂层的微观结构及性能。结果表明:超音速电弧涂层具有更加致密的结构,其平均孔隙率为0.95%,远低于普通电弧涂层;超音速电弧涂层与基体呈紧密结合,其结合强度为60 MPa,而普通电弧涂层与基体之间呈明显的分层状态,其结合强度仅为28 MPa;超音速电弧涂层具有良好的非晶态结构及致密性,使其具有远高于普通电弧涂层的硬度以及耐磨损性能,显微硬度高出普通电弧涂层32.27%,耐磨损性能是普通电弧涂层的2倍以上(是基体的14倍以上)。 相似文献
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《材料保护》2020,(4)
为了提高建筑用6063铝合金板表面抗静电能力,以硅烷偶联剂KH570改性处理纳米Si O2,再以其与疏水材料粉末组成静电喷涂材料,并以静电喷涂方式在建筑用6063铝合金板表面制备涂层,测试研究涂层的组织、润湿性及结合性能。结果表明:加入KH570进行改性得到的Si O2粒径降低,KH570在水解过程中形成-OH再跟SiO2表面-OH发生缩合反应。SiO2颗粒间存在许多孔隙,该结构有助于提高试样疏水性;随SiO2添加量增加,涂层接触角先增大后降低,都大于130°,综合分析将改性SiO2含量设定在20%的最优值;摩擦次数达到50次与100次的情况下,涂层依然表现出优异疏水性能,具备较好耐磨性;在划痕末端出现大块脱落,采用静电喷涂方法可以制备得到和基体形成更强结合能力的涂层。 相似文献
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本文选用目前治理火电站受热面管道中常用Fe-Al/Cr3C2的喷涂材料,结合高速电弧喷涂技术制备防腐涂层,利用扫描电镜、X-Ray衍射等试验手段对其腐蚀产物及腐蚀机理进行分析和探讨。为标准化选材提供理论依据。研究结果表明,喷涂后形成的涂层具有典型的层状结构,较高的结合强度和硬度,涂层的耐高温冲蚀性能良好,同时常温和高温耐磨损性能也较高,适用于电站锅炉"四管"的标准化防护。 相似文献
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铝合金材料具有密度低、强度高、易加工等优点,已被广泛应用于汽车和航空航天等领域。为了延长铝合金零件在磨损、腐蚀等环境下的服役寿命,目前开发了众多先进的表面工程技术,实现了对铝合金基体的性能强化。基于此,本文综述了等离子喷涂、电弧喷涂、火焰喷涂、激光重熔、氩弧重熔、冷喷涂、电火花沉积、激光熔覆、微弧氧化等九种表面技术对铝合金处理以强化耐磨性能的研究工作。大量研究发现,这些表面技术均在一定程度上提高了铝合金基体的耐磨性能。例如,等离子喷涂涂层可有效减轻高温条件下基体的磨损;重熔技术制备的涂层比喷涂涂层具有更高硬度和更优异的耐磨性能;采用硬质颗粒的冷喷涂技术制备的涂层具有显著提高的显微硬度;电火花沉积技术制备的沉积层内部均匀分布着高强度枝蔓状的Si相,能够极大地减小基体的摩擦系数。同时,本文总结了以上技术的优缺点及适用范围。例如,热喷涂效率高但易造成热应力集中,导致涂层与基体之间的结合强度降低;氩弧重熔在低熔点和易蒸发的金属和合金上重熔困难;激光重熔可消除大部分孔隙及夹杂的氧化物,但设备成本较高。最后,本文从采用多种技术复合处理、优化涂层工艺参数、加强新技术研发等方面,对未来铝合金基材表面耐... 相似文献
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《中国材料进展》2018,(12)
陶瓷基复合材料(CMC)由于具有较低的密度(高温合金的1/3~1/4)、较高的服役温度(比高温合金高200~240℃)以及良好的结构强度(高温合金的2倍),已成为未来大推重比航空发动机热端部件的首选材料。发动机服役过程中,热端部件完全暴露于空气气氛中,服役环境恶劣,以Si C/Si C为代表的CMC部件直接面临着腐蚀、烧蚀、冲刷等问题,因此急需开展一类高性能CMC热防护涂层即环境障涂层(EBCs)的研究。通过大气等离子喷涂在SiC/SiC CMC基体表面制备硅/莫来石/硅酸镱(Yb2SiO5)三层结构EBCs。为提高EBCs服役性能,对涂层样品进行镀Al表面改性即采用磁控溅射技术在涂层表面镀Al全包覆,然后对其进行真空热处理。在高温低真空下,涂层表面Al膜发生熔融并在毛细管力的作用下往多孔涂层内部渗透并与Yb_2SiO_5发生原位反应,在涂层表面形成一层致密α-Al_2O_3层。对喷涂态及镀Al表面改性涂层进行典型模拟服役环境性能对比实验,发现镀Al表面改性EBCs具有较好的抗高温水氧及耐CMAS(CaO-MgO-Al_2O_3-Si O_2)腐蚀性能。另外,通过实验观察,原位形成的α-Al_2O_3致密层对涂层的热循环性能无明显影响。 相似文献
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海洋环境下热喷涂锌、铝及其合金涂层防腐蚀机理研究概况 总被引:2,自引:0,他引:2
综述了国内外几十年来在不同海水环境中对热喷涂锌铝及其合金涂层防护性能和机理研究的成果.热喷涂锌铝及其合金涂层在海洋环境中具有优良的长效防护性能,锌具有优良的电化学保护性,铝具有比锌更好的化学稳定性,锌铝合金既保留了锌的电化学特点,又具有铝的化学稳定性能.指出了今后的研究重点应该是金属与有机复合层在浪花飞溅区苛刻腐蚀环境下界面的腐蚀规律和腐蚀机理的探讨,对金属与有机复合层界面的腐蚀原因在理论上做出了本质的解释,并能预测涂层体系的防腐蚀寿命. 相似文献
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Ti-Al双丝超音速电弧喷涂涂层的滑动磨损特性研究 总被引:5,自引:0,他引:5
为了提高铝合金(LY12)的表面耐磨性,采用钛、铝金属丝材和SAS-Ⅰ型超音速电弧喷涂设备,利用二次回归正交试验方法、有润滑滑动磨损试验、涂层显微组织和磨损表面形貌观察、XRD分析,定量分析了喷涂电压和喷涂距离对涂层滑动磨损体积的影响规律,并进行了喷涂工艺参数的优化及其与基体滑动磨损的对比试验.结果表明:在特定的磨损和喷涂条件下,当喷涂距离较小时,随喷涂电压的增大,涂层的体积磨损量逐渐减小;随着喷涂距离的增加,涂层的体积磨损量随喷涂电压的升高逐渐增大,并且喷涂距离越大,涂层的体积磨损量随喷涂电压增大的速率愈大.当喷涂电压比较低时,涂层的体积磨损量随喷涂距离的增大而降低,但是,随喷涂电压的逐渐升高,涂层的体积磨损量随喷涂距离的增大逐渐上升,并且,喷涂电压愈高,其随喷涂距离而增加的速率越快.当喷涂电压和喷涂距离分别为26V和0 236m时,涂层具有最佳的耐滑动磨损性能,根据该工艺参数制成的涂层,其滑动磨损体积仅为LY12铝合金的1/38.84.即在适当的工艺条件下,Ti-Al双丝超音速电弧喷涂涂层对LY12铝合金具有显著的表面耐磨强化作用. 相似文献
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为了提高2024铝合金的耐磨性,对其进行微弧氧化。利用扫描电镜(SEM)和X射线衍射仪(XRD)分析了涂层的微观组织结构和物相组成;采用高速往复摩擦磨损试验机对2024铝合金微弧氧化涂层在不同载荷下的磨损性能进行了研究,并采用白光三维形貌仪进行磨损形貌分析及磨损体积计算。结果表明:2024铝合金微弧氧化涂层是一种微孔结构,涂层相主要成分为α-Al_2O_3、γ-Al_2O_3,且Al_2O_3具有高硬度、耐磨损的优良特性,有利于提高铝合金的耐磨损性能;微弧氧化涂层的摩擦系数随着载荷的增加而减小,而磨损量随载荷的增加而增加,磨损机理为磨粒磨损。 相似文献
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Driven by economical and ecological reasons, thermoplastics based coatings were more and more used in automotive engines. Two design concepts, flame spraying and serigraphy PEEK coatings on light metal substrate, were introduced in this paper. The friction and wear behavior of PEEK based coatings were investigated systematically. Coatings with different crystallinities can be obtained when cooling speed is controlled. Among three sprayed coatings considered with different crystallinities, the one with highest crystallinity exhibits best friction and wear behavior under dry sliding condition. Under lubricated sliding condition, however, the amorphous coating gives lower friction coefficient. The micron particles such as SiC,MoS2 and graphite in composite coatings can improve significantly the coating wear resistance and have a impact on coating friction behavior. 相似文献
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Coatings for cylinder inner surfaces of aluminium motorunits deposited by MSIP-PVD-Process Consumers are making constant increasing demands on technical goods, especially on cars and their driving element, the engine. In Europe the degree of motorization is steadily increasing, but upon a high quality a high power ability is of great importance. The aim of development for a new engine generation are apart from a low fuel consumption, low pollutant emissions, good acoustical behaviour and low weight, the recycling ability and low production costs. There are rapid changes in the area of car development, attendant by consequences for the drive unit. Therefore there is a big need of innovative developments. With the background of intensifying competition in the whole world a innovative, flexible cost and quality effective research and development will be the precondition for business success [1]. To an increasing degree modern car engines are made from light metal alloys, above all aluminium. This type of engines are nearly exclusivly equipped with cylinder liners, made from cast iron. Because of the separate production combined with transport and storing this liners cause a lot of costs. Apart from the economic aspect the use of liners increases the weight of the engine and in the end causes a higher fuel consumption [1]. The main emphasis of this work is to show the possibilities and the potential, modern PVD coating technologies can do in the area of engine combustion chambers. It will be shown that PVD coating
- can be deposited on aluminum substrates, if the process control is adapted
- with both, flat cathods and specially developed stick cathods, can be deposited at the interior of cylinders can replace the use of cylinder liners and
- in principle can hold the loading of combustion engines in a model experiment
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铝合金活塞材料的研发与应用进展 总被引:1,自引:0,他引:1
金梅 《中国材料科技与设备》2012,(2):1-3,11
活塞作为汽车发动机中传递能量的一个非常重要的构件,对其材料具有特殊的要求:密度小、质量轻、热传导性好、热膨胀系数小;并具有足够的高温强度、耐磨和耐蚀性能、尺寸稳定性好。在传统的铸造铝硅活塞合金的成分优化和处理工艺的的研究还没有大的突破的情况下,科研工作者已经在寻求新的途径提高铸造铝舍金的极限强度。通过采用基体增强和新型活塞成型工艺,显著提高了活塞的性能。随着汽车发动机向高速化、大功率方向的发展,新型铸造铝舍金活塞复合材料的开发应用将成为一个发展趋势。 相似文献
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Rapid hard tooling by plasma spraying for injection molding and sheet metal forming 总被引:23,自引:0,他引:23
Amidst the harsh competition over the development of new products around the world, rapid prototyping, especially rapid tooling methods have received widespread attention. Amongst the rapid hard tooling methods, thermal spraying can manufacture metal molds without limitation of pattern size. However, it has the disadvantage that only soft metals with low melting points such as zinc alloy can be sprayed to original mold, such as a rapid prototyping model or a natural material pattern, due to their lack of heat resistance and shrinkage of spray metals. So the wear resistance of spray tool is poor, it can be used only for trial or small-lot production. In this study, attempts were made to improve the heat resistance by using composite materials made of ceramic and metal powders as the sprayed original mold materials, and using stainless steel, tungsten carbide alloy, iron–nickel–chromium alloy with excellent wear resistance as spraying materials, respectively. The results show that injection molding spray mold and sheet metal forming spray die can be made by transferring from natural patterns and rapid prototyping models. As the durability and dimensional accuracy of the sprayed tools has sharply improved, the tools can be used for mass production. 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