共查询到19条相似文献,搜索用时 406 毫秒
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超声波-电沉积Ni-Al_2O_3复合镀层的表面形貌及组织结构 总被引:1,自引:0,他引:1
采用超声波-电沉积方法在金属基体上制备纳米Ni-Al2O3复合镀层。研究了超声波频率、功率对制备复合镀层的影响。利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)对镀层微观组织、表面形貌进行观察和分析。结果表明:超声波的作用可有效解决纳米Al2O3微粒在镀液中的分散问题,使纳米Al2O3微粒均匀分布在复合镀层中,促进纳米Al2O3微粒与镀层基质金属的共沉积,并细化基质金属Ni的晶粒,获得了由镍晶(20~40 nm)和纳米Al2O3微粒构成的纳米复合镀层。 相似文献
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采用直流与射频共溅射技术制备Zr1-xSixN纳米涂层。通过改变Si靶溅射功率控制涂层中Si含量,研究了不同Si含量对Zr1-xSixN涂层的物相结构、晶粒尺寸、硬度和摩擦磨损性能的影响,探索了Zr1-xSixN纳米涂层的致硬机理。结果表明:Si的掺入影响Zr1-xSixN涂层的择优取向和相结构,随着Zr1-xSixN涂层中Si含量的增加,涂层截面的形貌由柱状晶转变为非柱状等轴晶,其结构的变化为:固溶体→nc-ZrN/α-Si3N4结构→非晶结构。涂层的晶粒尺寸在12~30nm之间。对于Si含量低于3.14%(摩尔分数)的Zr1-xSixN涂层,由于固溶强化作用使硬度随Si含量增加而增大,对于Si含量高于3.14%的Zr1-xSixN涂层,通过晶粒的转动和原子在晶界的移动能产生塑性形变,提高了涂层塑性形变能力,使得硬度下降。Zr1-xSixN涂层的耐磨损性能随Si含量的增加而增强。 相似文献
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以尿素为固体氮源、AlCl3·6H2O为铝源,通过溶液反应合成金属络合物前驱体Al(CON2H4)6Cl3,前驱体经过1000℃煅烧,制备得到球形h-AlN纳米颗粒。研究了气氛压力及合成时间对AlN纳米颗粒形貌的影响及AlN的形核生长机制。结果表明:在0.1~0.2 MPa的N2压力下,球状AlN颗粒由<10 nm的等轴状细小晶粒与非晶相团聚而成,直径为320~460 nm;随着N2压力增至0.5 MPa,球状AlN直径增加至650 nm,团聚体中棒状AlN晶体出现,随着烧结时间延长,棒状晶尺寸增大,数量增加。AlN纳米颗粒由前驱体分解形成的AlCl3和NH3反应而成,随着N2压力增大,坩埚内气相饱和度增大,促进了AlN的形核与生长,使得非晶相含量减少,AlN结晶度提高。 相似文献
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《Ceramics International》2021,47(23):33338-33352
Niobium carbide composite coatings were prepared on titanium alloy surface by plasma spraying NbC–Al2O3, Nb–SiC and Nb–SiC–Al composite powders, respectively. The phase composition, microstructure and formation mechanism of the three composite coatings were analyzed and their microhardness, toughness and scratch resistance were compared. The phases of the NbC–Al2O3 system did not change during the plasma spraying process, and new phases (Nb2C, NbC and Nb3Si) were formed in the Nb–SiC and Nb–SiC–Al systems. TEM results of the Nb–SiC composite coating indicate that the new phases nanocrystalline Nb2C, submicron NbC and nanocrystalline Nb3Si were formed during the plasma spraying process. Compared with the NbC–Al2O3 composite coating, the microstructure of the Nb–SiC and the Nb–SiC–Al composite coatings were uniform, and the porosity were relatively low, and the hardness was higher. The Nb–SiC–Al composite coating was denser than the Nb–SiC composite coating, the lamellar structure was obvious and the number of pores in the coating was the least, which is attributed to the better molten state of the composite powder by the addition of the Al to the Nb–SiC system. The Nb–SiC–Al composite coating had better toughness and scratch resistance. 相似文献
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《Ceramics International》2021,47(24):34072-34085
ZrN-based coatings have attracted significant attention due to their high hardness and outstanding thermal properties. In this research, ZrN, TaN, and (Zr, Ta) N coatings with different Ta content (ZrTaN-1 coating with 30 at.% Ta content and ZrTaN-2 coating with 60 at.% Ta content) were prepared with a double-cathode glow plasma alloy (DGPA). The influence of Ta content on the phase composition, microstructure, mechanical performance, oxidation and tribological behaviour of the coatings was comparatively studied. The results illustrated that the (Zr, Ta) N coatings with different Ta content crystallized in NaCl-type structures. The lattice constants of the (Zr, Ta) N coatings decreased with increasing Ta content because the Ta–N bonds (0.227 nm) were shorter than the Zr–N (0.230 nm) bonds, which confirmed that Zr was successfully substituted with Ta. The oxidation resistivity of the (Zr, Ta) N coatings exhibited minimum mass gain values of 0.55 mg/cm2, 5.12 mg/cm2, and 17.08 mg/cm2 at 650~850 °C with a Ta content of 60 at.%. The addition of Ta effectively reduced the thermal stress of the coatings and avoided cracking and peeling at high temperatures. In addition, high-temperature tribological experiments showed that the wear rate of the (Zr, Ta) N coatings at 500 °C was low and stable and was only 32.9% of that of the ZrN coating under the same conditions. This was attributed to the formation of a dense (Zr, Ta)-rich oxide on the coating surface. 相似文献
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《Ceramics International》2023,49(4):6409-6418
Ni-based composite coatings reinforced by TiBX/TiXNiY/TiC with different Ti6Al4V contents were precipitated on a 35CrMoV substrate via laser cladding. The phase composition, elemental distribution, and precipitated phases of the coatings were characterised using X-ray diffraction, energy dispersive X-ray spectroscopy, scanning electron microscopy, and transmission electron microscopy. The mechanical and tribological properties of the cladding layer were also characterised. The results showed that the coating contained TiB2, TiC, TiB, Ni3Ti, and NiTi2 phases with uniform elemental distribution and grain refinement. A schematic of the growth model and precipitation sequence of the reinforced phases was generated. The microstructure, elemental segregation, hardness, and friction behaviour of the cladding layer were significantly influenced by the addition of Ti6Al4V. The optimal microstructure and best mechanical properties were obtained by the addition of 4 wt% Ti6Al4V, with that coating possessing a hardness, average friction coefficient, and wear volume of 770.8 HV1, 0.180 and 6132 um3, respectively. 相似文献
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R.J. Narayan W. Wei C. Jin M. Andara A. Agarwal R.A. Gerhardt Chun-Che Shih Chun-Ming Shih Shing-Jong Lin Yea-Yang Su R. Ramamurti R.N. Singh 《Diamond and Related Materials》2006,15(11-12):1935
In this study, the microstructural, mechanical, adhesion, and hemocompatibility properties of nanocrystalline diamond coatings were examined. Microwave plasma chemical vapor deposition (MPCVD) was used to deposit nanocrystalline diamond coatings on silicon (100) substrates. The coating surface consisted of faceted nodules, which exhibited a relatively wide size distribution and an average size of 60 nm. High-resolution transmission electron microscopy demonstrated that these crystals were made up of 2–4 nm rectangular crystallites. Raman spectroscopy and electron diffraction revealed that the coating contained both crystalline and amorphous phases. The microscratch adhesion study demonstrated good adhesion between the coating and the underlying substrate. Scanning electron microscopy and energy dispersive X-ray analysis revealed no crystal, fibrin, protein, or platelet aggregation on the surface of the platelet rich plasma-exposed nanocrystalline diamond coating. This study suggests that nanocrystalline diamond is a promising coating for use in cardiovascular medical devices. 相似文献
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V. Yu. Filimonov V. I. Yakovlev M. A. Korchagin M. V. Loginova A. S. Semenchina A. V. Afanas’ev 《Combustion, Explosion, and Shock Waves》2008,44(5):591-596
This paper considers the mechanisms of structure formation during gas detonation spraying of coatings of TiAl3 and Ni3Al intermetallic compounds produced under equilibrium and nonequilibrium synthesis conditions. The coating sprayed from TiAl3 has the same phase composition as the initial powder, regardless of the synthesis conditions. During spraying of Ni3Al, the structure of the coating also does not depend on the synthesis conditions and consists of two phases — Ni3Al and NiAl, with the crystal structure varying along the coating thickness. Comparative impact abrasion tests of the coatings
showed advantages of TiAl3 coatings over coatings based on Ni3Al and titanium diboride.
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Translated from Fizika Goreniya i Vzryva, Vol. 44, No. 5, pp. 106–111, September–October, 2008. 相似文献
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K. Polychronopoulou C. Rebholz M.A. Baker L. Theodorou N.G. Demas S.J. Hinder A.A. Polycarpou C.C. Doumanidis K. Böbel 《Diamond and Related Materials》2008,17(12):2054-2061
This study describes the correlation between microstructure, mechanical and tribological properties of TiCx coatings (with x being in the range of 0–1.4), deposited by reactive magnetron sputtering from a Ti target in Ar/C2H2 mixtures at ~ 200 °C. The mechanical and tribological properties were found to strongly depend on the chemical composition and the microstructure present. Very dense structures and high hardness, combined with low wear rates and friction coefficients, were observed for coatings with chemical composition close to TiC. X-ray diffraction and X-ray photoelectron spectroscopy analysis, used to evaluate coating microstructure, composition and relative phase fraction, showed that low carbon contents in the coatings lead to sub-stoichiometric nanocrystalline TiCx coatings being deposited, whilst higher carbon contents gave rise to dual phase nanocomposite coatings consisting of stoichiometric TiC nanocrystallites and free amorphous carbon. Optimum performance was observed for nanocomposite TiC1.1 coatings, comprised of nanocrystalline nc-TiC (with an average grain size of ~ 15 nm) separated by 2–3 monolayers of an amorphous a-DLC matrix phase. 相似文献