共查询到19条相似文献,搜索用时 78 毫秒
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采用低压等离子喷涂(LPPS)技术,用2种不同粒径的粉末,在铜基体上制备了厚度为0.7 mm以上的W涂层.通过扫描电镜(SEM)研究了涂层的微观形貌,并对粉末对W涂层的显微结构、结合强度、氧含量及热导率的影响进行了探讨.结果表明:细小粒径W粉所制备的W涂层孔隙率较低,但涂层存在明显的分层;粗粉所制备的W涂层结构均匀,涂层的内聚力与热导率分别达到了38 MPa和98.06 W/m·k,远高于细W粉涂层的23 MPa和75.36W/m·k.细W粉涂层较低的性能和其严重的分层有关. 相似文献
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反应等离子喷涂TiN复相陶瓷涂层的研究 总被引:2,自引:0,他引:2
采用反应等离子喷涂技术制备了TiN复相涂层,并分析了复相涂层的组织及其性能.结果表明复相涂层主要由TiN相组成,并含有少量的钛的氧化物;复相涂层具有典型的层状组织结构,且层与层之间结合较好;复相涂层是由小于100 nm晶粒组成,属于纳米复合材料,因而复相涂层不仅具有高硬度,而且具有远优于Al2O3涂层的断裂韧性.与M2钢相比,复合涂层具有较高的耐磨性能. 相似文献
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在汽车上使用轻质铝合金发动机可以有效减少燃油消耗和环境污染,但铝合金的耐磨损性能较差,从而造成发动机工作过程中气缸壁面容易磨损。利用表面改性技术对铝合金表面进行强化处理,可以满足其作为滑动部件在高载荷条件下的使用要求。灰铸铁较低的成本和其中石墨的自润滑作用,使其成为铝合金发动机气缸表面保护涂层材料的首选。等离子喷涂技术以其高效率和灵活性在表面强化领域受到广泛应用。因此,利用等离子喷涂制备灰铸铁涂层成为改善铝合金发动机气缸表面耐磨性的有效方法之一。但是,由于等离子喷涂过程中熔滴冷却速度极快,等离子喷涂很难得到含大量石墨组织的灰铸铁涂层。以调控灰铸铁涂层中的石墨含量为目的,总结了等离子喷涂灰铸铁涂层的研究现状,以及基体温度、颗粒尺寸、添加合金元素等对熔滴冷却速度的影响,并以此为基础,结合凝固理论分析了在涂层中保留灰铸铁粉末中的石墨组织的可行性,同时分析了在铸铁涂层中保留石墨所面临的主要问题,并提出了解决这些问题的主要措施。最后就在等离子喷涂灰铸铁涂层中保留石墨的研究方向进行了展望。 相似文献
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采用反应等离子喷涂技术制备了TiN涂层,并收集了少量TiN颗粒;采用SEM对涂层和TiN颗粒的横断面肜貌进行分析,研究了喷涂过程中的反应过程和涂层的形成过程.结果表明:Ti粉与N_2的反应为燃烧合成反应.反应过崔中释放出大量的热量,此反应在颗粒的表面进行;TiN涂层具有典型的层状组织结构,且层与层之间结合较好. 相似文献
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反应等离子喷涂 TiN 涂层的研究进展 总被引:3,自引:3,他引:0
TiN具有硬度高、韧性好、摩擦系数小、化学性能稳定等优点,广泛应用于刀具、装饰、表面防护等领域。目前制备TiN涂层的方法有很多,如气相沉积、热喷涂、电镀等,反应等离子喷涂则是最常用的金属-陶瓷复合涂层制备方法。概述了反应等离子喷涂技术的基本原理和分类,包括反应等离子喷涂涂层的形成过程及工艺的优缺点。综述了反应等离子喷涂TiN涂层的喷涂工艺及性能的研究进展,包括涂层的制备方法(原位合成法、烧结破碎法)和性能特点,重点分析了涂层的力学性能、耐磨损性能、耐腐蚀性能,并提出了可以依靠热处理工艺或封孔技术来提高涂层的耐腐蚀性能。依据实验和查阅的文献,反应等离子喷涂结合了自蔓延高温合成技术和等离子喷涂技术,可以制备质量优良的厚TiN涂层(500μm),是一种新型的低成本涂层制备技术,但是反应等离子喷涂制备TiN涂层存在孔隙率较高(5%~10%)、结合强度较低(50 MPa)的问题。分别从技术、设备、工艺、后处理四个方面总结了改善涂层质量的相应措施,展望了今后的研究发展方向。 相似文献
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TiC/Fe-Ni金属陶瓷复合涂层反应等离子喷涂研究 总被引:2,自引:0,他引:2
以钛铁粉、镍粉、铁粉和碳的前驱体(蔗糖)为原料采用前驱体碳化复合技术制备了Ti-Fe-Ni-C系反应热喷涂粉末,并通过等离子喷涂(RPS)技术原位合成并沉积了TiC/Fee-Ni金属陶瓷复合涂层.采用XRD、SEM和EDS对喷涂粉末和涂层的成分、组织结构进行了分析.研究表明该反应喷涂粉末粒度均匀、无有害相生成;所得涂层由不同TiC颗粒含量的TiC/Fe-Ni复合片层组成;TiC颗粒大致呈球形,粒度呈纳米级;所获涂层在相同条件下耐磨性是Ni60涂层的7倍. 相似文献
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真空等离子喷涂WC—Co涂层性能研究 总被引:1,自引:0,他引:1
研究了真空等离子喷涂(VPS)WC—Co涂层的性能,如涂层的结合强度、显微硬度、孔隙率、相组成和碳含量等。并与大气等离子喷涂(APS)的WC—Co涂层的性能作了对比。结果表明VPS的WC—Co涂层性能明显优于APS的WC—Co涂层的性能。 相似文献
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Tribological properties of TiC-Fe coatings obtained by plasma spraying reactive powders 总被引:1,自引:0,他引:1
Titanium carbide-based coatings have been considered for use in sliding wear resistance applications. Carbides embedded in
a metal matrix would improve wear properties, providing a noncontinuous ceramic surface. TiC-Fe coatings obtained by plasma
spraying of spray-dried TiC-Fe composite powders containing large and angular TiC particles are not expected to be as resistant
as those containing TiC particles formed upon spraying. Coatings containing 60 vol% TiC dispersed in a steel matrix deposited
by plasma spraying reactive micropellets, sintered reactive micropellets, and spray-dried TiC-Fe composite powders are compared.
The sliding wear resistance of these coatings against steel was measured following the test procedure recommended by the Versailles
Advanced Materials and Standards (VAMAS) program, and the inherent surface porosity was evaluated by image analysis. Results
show that, after a 1-km sliding distance, TiC-Fe coatings obtained after spraying sintered reactive powders exhibit scar ring
three times less deep than sprayed coatings using spray-dried TiC-Fe composite powders. For all coatings considered, porosity
is detrimental to wear performance, because it generally lowers the coating strength and provides cavities that favor the
adhesion of metal. However, porosity can have a beneficial effect by entrapping debris, thus reducing friction. The good wear
behavior of TiC-Fe coatings manufactured by plasma spraying of sintered reactive powders is related to their low coefficient
of friction against steel. This is due to the microstructure of these coatings, which consists of 0.3 to 1 μm TiC rounded
particles embedded in a steel matrix.
Presented at the International Conference on Metallurgical Coatings and Thin Films, ICMCTF-92, Apr 6–10, 1992, San Diego. 相似文献
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Utilizing self-propagating high-temperature synthesis (SHS) reactive spraying technology, the feeding self-combustion agglomerated particles composed of Ti, B4C and C powders, TiC-TiB2 multi-phase ceramic coatings were prepared on the steel substrates. Orthogonal experiment was carried out to optimize the spraying parameters. The phase component and microstructure of the coating fabricated at the optimized parameters were studied by XRD and SEM. The reactive mechanism in flying agglomerated particles was discussed. The optimized conditions, spraying distance of 220 mm, powders delivering gas pressure of 0.3 MPa and preheating temperature of 240 ℃ to sprayed particles, were obtained from orthogonal experiment. For the coating, porosity of 2.5% and HV l 595 are achieved under the optimized parameters. The coatings are mainly composed of TiC0.3N0.7, TiB2 and a little TiO2. The SEM analysis shows the morphology of TiC0.3N0.7 matrix in which the fine granular TiB2 crystals evenly disperse. It is concluded that, as solo reactive units, the agglomerated particles would finally form into the coatings after going through four successive stages in the flame, which are, respectively, pregnant reaction, flight combustion, collision and structure transformation and solidification. The solid diffusion and dissolution-precipitation are the two mechanisms to control the synthesis reaction. 相似文献
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Electrotribological applications require materials with both high electrical conductivity and wear resisance. For this purpose,
a copper- base plasma sprayed coating containing titanium diboride particles was developed. The process for fabricating this
CU- TiB2 coating consists of plasma spraying reactive powders that contain a Cu- Ti alloy and boron. The reaction between the copper
alloy and boron proceeds in different steps going from solid- state diffusion of titanium and copper to the synthesis of TiB2 in a liquid below 1083 ‡C. Plasma sprayed copper coatings contain finer TiB2 crystals than Cu- TiB2 materials synthesized in a furnace at 1200 ‡C. Coatings with 25 vol% TiB2 have hardnesses that are comparable to Cu- Co-
Be and Cu- Ni- Be alloys and to Cu- W and Cu- Mo alloys used in spot welding. Their low electrical resistivity of 52 ΜΩ cm
could be increased by lowering the oxygen content with coatings and controlling the formation of TiB2 clusters, the titanium content in solution in copper remaining low after the synthesis reaction. 相似文献
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WEI Zhiqiang XIA Tiandong FENG Wangjun DAI Jianfeng WANG Qing LI Weixue YAN Pengxun 《稀有金属(英文版)》2006,25(2):172-176
Copper nanoparticles were successfully prepared in large scale by means of anodic arc discharging plasma method in inert atmosphere. The particle size, specific surface area, crystal structure, and morphology of the samples were characterized by X-ray diffraction (XRD), BET equation, transmission electron microscopy (TEM), and the corresponding selected area electron diffraction (SAED). The experimental results indicate that the crystal structure of the samples is fcc structure the same as that of the bulk materials. The specific surface area is 11 m^2/g, the particle size distribution is 30 to 90 nm, and the average particle size is about 67 nm obtained from TEM and confirmed from XRD and BET results. The nanoparticles with uniform size, high purity, narrow size distribution and spherical shape can be prepared by this convenient and effective method. 相似文献
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0Introduction Asakindofsurfaceengineeringtechnology,thermal sprayingcanprovideprotectiveorfunctionalcoatings whicharewidelyusedinmanyindustrieslikechemistryin dustry,papermaking,electricengineering,powerplant, aviation,automobileproducing,steelmill,glass… 相似文献
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WEI Zhiqiang ) XIA Tiandong) FENG Wangjun) DAI Jianfeng) WANG Qing) LI Weixue) and YAN Pengxun) ) School of Sciences Lanzhou University of Technology Lanzhou China ) College of Materials Science Engineering Lanzhou University of Technology Lanzhou China ) Institute of Plasma Metal Materials Lanzhou University Lanzhou China 《稀有金属(英文版)》2006,(2)
1. Introduction Metal nanoparticles exhibit novel physical and chemical properties owing to the small size effect, surface effect, quantum size effect, and quanta tun-nel effect [1-4]. In recent years, the research and de-velopment for metal nanoparticles have attracted significant interest and is still the subject of intense investigation owing to their intriguing properties and various potential applications [5-7]. Because the properties depend strongly on the details of particle size, speci… 相似文献
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J. Kitamura S. Usuba Y. Kakudate H. Yokoi K. Yamamoto A. Tanaka S. Fujiwara 《Journal of Thermal Spray Technology》2003,12(1):70-76
A new system of electromagnetically accelerated plasma spraying (EMAPS) consisting of a pulsed high-current arc-plasma gun
and a large flow rate pulsed powder injector has been developed to synthesize a hard and dense coating of boron carbide (B4C) with a high adhesion. The plasma gun with a co-axial cylindrical electrode configuration generates electromagnetically
accelerated arc plasma with a typical velocity and maximum pressure of 1.5–3.0 km/s and 1 MPa, respectively, by discharging
a pulsed high current of about 100 kA in peak and about 300 μsec of duration. The heating and accelerating of source powder
are accomplished by injecting it into the inter-electrode space of the gun prior to the plasma generation using a newly developed
pulsed powder injector that enables a gram of powder to be injected within 1 ms with precisely controlled time delay. With
this system, hard B4C coatings with a high adhesion and crystallinity were successfully formed on mirror-polished stainless (SUS304) substrates
without a binder. 相似文献