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采用机械合金化法制备FeAl合金粉末,并用冷喷涂法将其沉积在基体——2520耐热不锈钢上,通过后续热处理原位制备了致密的FeAl金属间化合物涂层,研究了该涂层从室温至800℃下的耐磨损性能.结果表明,冷喷涂FeAl合金涂层组织致密,具有不同于传统热喷涂涂层的层状组织结构,该涂层在950℃下热处理后转变为无粒子界面的FeAl金属间化合物涂层;冷喷涂FeAl金属间化合物涂层在400~800℃的范围内磨损性能随着温度的升高不断提高;在700℃下FeAl金属间化合物涂层的磨损失重仅为2520耐热不锈钢的40%. 相似文献
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过程控制剂对机械合金化Fe-48Al粉末特性的影响 总被引:1,自引:0,他引:1
研究了过程控制剂(PCA)-无水乙醇和硬脂酸对机械合金化Fe-48Al(Al原子分数为48%,下同)粉末特性的影响.利用激光粒度仪、扫描电镜和X射线衍射仪分别研究了球磨粉末的粒度、形貌和热处理前后物相结构的变化规律.结果表明,以无水乙醇作PCA时,Fe-48Al的机械合金化速度较快,粉末粒度较小呈不规则薄片状;以硬脂酸作PCA则有利于球磨粉末形态向厚片状或近球形转化.两种粉末经12h球磨后,仍保持固溶体结构;经1100℃真空热处理后,两者均可转变为FeAl(B2)金属间化合物,但无水乙醇作PCA的球磨粉末中Al2O3生成量相对较多. 相似文献
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反应等离子喷涂Fe-Al2O3-FeAl2O4复合涂层的反应机理研究 总被引:3,自引:0,他引:3
金属/陶瓷复合涂层具有金属的韧性和陶瓷的高强度、高硬度等优点,利用反应等离子喷涂技术将Fe2O3/Al复合粉制备成金属/陶瓷复合涂层,以X射线衍射(XRD)、扫描电镜(SEM)、能谱仪(EDS)等分析技术研究了该复合涂层的反应机理和涂层性能.结果表明:涂层具有以层状的FeAl2O4、Al2O3为骨架,球形的Fe及部分FeAl为弥散相的复合组织;复合粉体反应形成涂层的过程是分步进行的,而且在熔滴到达基体后部分反应仍继续进行;一定程度上,由于反应过程受到Al元素的扩散限制,同时等离子喷涂的冷却速度较高,使得涂层中主要含有FeAl2O4及少量的FeO. 相似文献
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金属/陶瓷复合涂层具有金属的韧性和陶瓷的高强度、高硬度等优点,利用反应等离子喷涂技术将Fe2O3/Al复合粉制备成金属/陶瓷复合涂层,以X射线衍射(XRD)、扫描电镜(SEM)、能谱仪(EDS)等分析技术研究了该复合涂层的反应机理和涂层性能。结果表明:涂层具有以层状的FeAl2O4、Al2O3为骨架,球形的Fe及部分FeAl为弥散相的复合组织;复合粉体反应形成涂层的过程是分步进行的,而且在熔滴到达基体后部分反应仍继续进行;一定程度上,由于反应过程受到Al元素的扩散限制,同时等离子喷涂的冷却速度较高,使得涂层中主要含有FeAl2O4及少量的FeO。 相似文献
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采用机械合金化制备40vol%cBN-NiCrAl金属陶瓷复合结构粉末,采用冷喷涂制备了40%cBN-NiCrAl(体积分数)金属陶瓷复合结构涂层。研究了机械合金化过程对粉末的相组成、晶粒尺寸以及显微组织的影响。采用扫描电子显微镜和X射线衍射分别表征不同球磨时间下粉末以及冷喷涂涂层的显微组织和相结构。采用Scherrer公式估算不同球磨时间下粉末以及冷喷涂涂层中合金基体相的晶粒尺寸。结果表明,40vol%cBN-NiCrAl金属陶瓷粉末球磨40h后,基体的平均晶粒尺寸达到~50nm;复合结构涂层组织致密,硬质颗粒在合金基体中分布均匀。喷涂过程中,粉末相结构未发生变化,晶粒尺寸也未发生明显的长大。测试表明涂层的显微硬度约为1170HV0.3。 相似文献
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为解决非晶粉末价格昂贵、成型困难等问题,采用真空气雾化法制备了Ni FeCrMoNbBSi合金粉末,利用火焰喷涂焰流温度高、冷凝速度快有利于形成非晶相等特点,经火焰喷涂后制备了镍基非晶涂层。通过XRD、SEM、EDS、TEM等对粉末和涂层的相组织结构、表面形貌和微观特征进行了表征。结果表明:Ni FeCrMoNbBSi合金粉末形貌为球形或近球形,主要由晶体相FeNi3和Ni CrFe固溶体组成,非晶含量较少。制备的Ni基非晶涂层组织结构致密,主要由非晶相和Cr2Ni3金属间化合物组成,非晶含量可达70%(体积分数)。 相似文献
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高速电弧喷涂Fe-Al/WC复合涂层的组织和性能 总被引:18,自引:2,他引:16
采用粉芯丝材和高速电弧喷涂技术(HVAS)原位合成了Fe-Al/WC金属间化合物基复合涂层,并研究了涂层的显微组织和性能。结果表明,铁铝涂层的成分为Fe-13.87Al-17.27C-3.35W-2.59Ni-1.27Cr-18.140(原子分数,%),主要相是Fe3Al,FeAl和α-Fe相,还有少量WC,W2C和Al2O3。TEM观察的涂层的扁平颗粒内是微晶组织,在一些区域还发现有非晶组织,说明在高速电弧喷涂过程中达到了很高的冷却速度。涂层具有相对较高的结合强度和显微硬度,以及较低的密度和孔隙率。 相似文献
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It is difficult to deposit dense intermetallic compound coatings by cold spraying directly using compound feedstock powders due to their intrinsic low temperature brittleness. A method to prepare intermetallic compound coatings in-situ employing cold spraying was developed using a metastable alloy powder assisted with post heat treatment. In this study, a nanostructured Fe(Al)/Al2O3 composite alloy coating was prepared by cold spraying of ball-milled powder. The cold-sprayed Fe(Al)/Al2O3 composite alloy coating was evolved in-situ to FeAl/Al2O3 intermetallic composite coating through a post heat treatment. The effect of heat treatment on the phase formation, microstructure and microhardness of cold-sprayed Fe(Al)/Al2O3 composite coating was investigated. The results showed that annealing at a temperature of 600 °C results in the complete transformation of the Fe(Al) solid solution to a FeAl intermetallic compound. Annealing temperature significantly influenced the microstructure and microhardness of the cold-sprayed FeAl/Al2O3 coating. On raising the temperature to over 950 °C, diffusion occurred not only in the coating but also at the interface between the coating and substrate. The microhardness of the FeAl/Al2O3 coating was maintained at about 600HV0.1 at an annealing temperature below 500 °C, and gradually decreased to 400HV0.1 at 1100 °C. 相似文献
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Reaction synthesis principles have been extended to plasma spraying to obtain coatings consisting of mixed oxide phases and iron aluminides. Elemental powders of iron and aluminium were fed through a d.c. plasma torch to deposit intermetallic coatings on carbon steel substrates. Carbon steel substrates were also pre-heated with a plasma flame to create an iron oxide surface on the substrate such that an exothermic thermite reaction takes place when molten splats of aluminium impinge the pre-heated substrate at sub- or supersonic velocities. A thermite reaction between iron oxide and aluminium allowed the formation of alumina, FeAl2O4, iron, and iron aluminide phases. The presence of FeAl2O4 and Al2O3 increased the surface hardnesses of the coating, and the hardnesses of the coatings are significantly higher than the hardnesses of steel substrate, and aluminium particles. X-ray analysis of the coatings, microstructural observations, and microhardness measurements suggest that plasma spraying conditions can be tailored to obtain coatings with high hardness values with in situ synthesized reinforcements (spinel and alumina) or iron aluminide phases. Aluminium-rich phases were observed in the as-deposited coatings when a mixture of aluminium and iron or aluminium and nickel were fed through the plasma gun in ratios equivalent to Fe3Al, FeAl, Ni3Al, and NiAl. In some cases, annealing allowed the formation of iron-rich or nickel-rich aluminide phases. High solidification rates of molten splats allowed very limited diffusional reactions between the splats of aluminium and iron, or aluminium and nickel because the available diffusional time for exothermic interfacial reactions is limited to a fraction of a second at best. Oxidation of part of the aluminium led to the formation of alumina in the as-deposited coatings, and therefore, a vacuum plasma spraying technique is desirable to obtain intermetallic phases. The results suggest that reactive spraying will allow deposition of coatings by utilizing the heats of reaction between the constituents, and reactive spraying will broaden the engineering applications of reaction synthesis techniques. 相似文献
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《Composites Science and Technology》2007,67(11-12):2292-2296
The goal of this work was to study the development of microstructure of the coatings cold sprayed from nanocomposite powders TiB2–43 vol.%-Cu containing titanium diboride particles 50–100 nm in size. Titanium diboride phase was in situ produced in a copper matrix using high-energy mechanical milling of Ti, B and Cu powders and self-propagating high-temperature synthesis. The coatings were fabricated on a copper substrate. The microstructure of the coatings was studied by scanning electron microscopy and energy dispersive spectroscopy. Due to low-temperature conditions of spraying, nanostructured coatings were produced retaining the microstructure of the nanocomposite powder being sprayed. Despite the high content of titanium diboride and the difference in plasticity of the phases, the coatings were fully dense and composed of closely packed powder particles. Considering the results of this study, cold spraying of nanocomposite mechanically milled powders can be recommended as a promising way for fabrication of nanostructured coatings. 相似文献
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Laser surface alloying of Mo, WC and Mo–WC powders on the surface of Ti6Al4V alloys using a 2 kW Nd-YAG laser was performed. The dilution effect upon the microstructure, microhardness and wear resistance of the surface metal matrix composite (MMC) coating was investigated. With a constant thickness of pre-placed powder, the dilution levels of the alloyed layers were found to increase with the incident laser power. The fabricated surface MMC layer was metallurgically bonded to the Ti6Al4V substrate. The microhardness of the fabricated surface layer was found to be inversely proportional to the dilution level. The EDAX and XRD spectra results show that new intermetallic compounds and alloy phases were formed in the MMC layer. With the existence of Mo content in the pre-placed powder, the β-phase of Ti in the MMC coating can be retained at the quenching process. With increasing weight percentage content of WC particles in the Mo–WC pre-pasted powder, the microhardness and sliding wear resistance of the laser surface coating were increased by 87% and 150 times, respectively, as compared with the Ti6Al4V alloy. The surface friction of the laser-fabricated MMC coatings was also decreased as compared with the worn Ti6Al4V substrate. 相似文献
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目前Fe-Si涂层的相关研究较少。为制备Fe-Si金属间化合物复合涂层并改善其力学性能,采用氮弧.熔覆原位合成的方法在Q235钢表面制备Fe-Si涂层和Fe-Si/Al2O3金属间化合物复合涂层,利用金相电子显微镜、X射线衍射仪(XRD)、冲蚀磨损试验机、高温氧化炉等设备对涂层的显微组织、耐冲蚀磨损性能和抗高温氧化性能进行测试与分析。结果表明:Fe-Si熔覆层由Fe3Si和FeSi相构成,添加A12O3后熔覆层除存在Fe3Si,FeSi外还有AI2O3相产生;Fe-Si/Al2O3熔覆层耐冲蚀磨损性优于Fe-Si熔覆层,最高为基体的4.65倍;熔覆层的耐高温氧化性能相对基体明显提高,在800℃下Fe-Si熔覆层和Fe-Si/Al2O3熔覆层相比于基体分别提高了5.50和5.83倍。 相似文献
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F Cardellini V Contini R Gupta G Mazzone A Montone A Perin G Principi 《Journal of Materials Science》1998,33(10):2519-2527
High-energy ball milling has been performed on FexAl1-x powder mixtures with x=0.75, 0.50, 0.25 and 0.20. X-ray diffraction, Mossbauer spectroscopy and electron microscopy have been used to characterize the samples milled for different times and annealed in a differential scanning calorimeter. It is found that, during milling, there is diffusion of both elements into each other, with a prevalence of iron diffusion into aluminium, at least in the early stages of the process. This behaviour is more pronounced in the aluminium-rich samples. The growth of the Fe(Al) and Al(Fe) solid solutions has been observed for x0.5, different from the lower iron concentrations where the Fe(Al) phase has not been detected. The annealing of pre-milled samples favours the formation, depending on the sample composition and on the annealing temperature, of intermetallic phases such as Fe3Al, FeAl, Fe2Al5 and FeAl3. © 1998 Chapman & Hall 相似文献
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为改善Fe-Al金属间化合物的力学性能及抗高温氧化性能,利用氩弧熔覆方法在Q235钢上制备了Fe-Al熔覆层和Fe-Al/Al_2O_3熔覆层。采用金相显微镜、X射线衍射仪、硬度计、磨粒磨损试验机对氩弧熔覆涂层进行显微组织结构观察和磨损性能测试。采用高温氧化试验对涂层的耐高温氧化性进行了研究。结果表明:Fe-Al熔覆层形成FeAl和Fe_3Al相,而Fe-Al/Al_2O_3熔覆涂层含有FeAl、Fe_3Al和Al_2O_3相;熔覆层的耐磨粒磨损性能优于基体且Fe-Al/Al_2O_3熔覆层优于Fe-Al熔覆层;熔覆层的耐高温氧化性能明显提高,在700℃下,Fe-Al熔覆层和Fe-Al/Al_2O_3熔覆层相比于基体分别提高了4.46和5.68倍。 相似文献