共查询到20条相似文献,搜索用时 171 毫秒
1.
采用超细碳化钨和草酸钴为原料通过喷雾干燥造粒、氮气保护烧结、氢气还原等工艺得到WC-12Co超细热喷涂粉末材料.通过超音速火焰喷涂(HVOF)制备超细WC-12Co耐磨涂层.通过扫描电子显微镜对制备的WC-12Co超细热喷涂粉末材料及超细结构耐磨涂层的微观组织结构进行分析.对制备的超细结构耐磨涂层的结合强度、硬度进行表征.结果表明制备的WC-12Co超细热喷涂粉末材料适合于超音速火焰喷涂制备超细WC-12Co耐磨涂层,制备的超细WC-12Co耐磨涂层性能优异. 相似文献
2.
3.
以纯氧氯化锆、氧化钇和硝酸为原料,以碳酸铵沉淀剂,采用共沉淀法制备碳酸锆与碳酸钇的混合物,经喷雾干燥制粒、热处理后得到纳米YPSZ团聚粉末.由等离子喷涂方法制备了YPSZ涂层,用XRD、SEM等分析手段观察和确定涂层的物相组成和显微结构. 相似文献
4.
5.
随着纳米科学技术的快速发展,纳米材料被成功地应用到热喷涂领域。研究表明,热喷涂纳米陶瓷涂层比传统陶瓷涂层具有更高的结合强度、韧性、热震性能、耐磨抗蚀性能和可加工性。这种热喷涂纳米陶瓷涂层是利用纳米粉末为原料经过特殊的再造粒过程得到可喷涂喂料,然后方可制备出纳米结构陶瓷涂层。与传统微米结构陶瓷涂层相比,该纳米陶瓷涂层的韧性、结合强度、抗热震性能高1~2倍,耐磨性能高4~8倍,抗疲劳性能提高10倍。发展这样的国际领先的先进表面工程新材料技术,对推动我省的科技和产业发展无疑有重大的战略和经济意义。可以促进我省传统产业的结构调整和产品的升级换代,可以提高我省产品的市场竞争力和我省企业的活力和经济效益。 相似文献
6.
采用大气等离子喷涂了一种新型的纳米La2Zr2O7热障涂层,比较了纳米La2Zr2O7和纳米ZrO2涂层的隔热性能.结果表明,与纳米YPSZ涂层相比,纳米结构的La2Zr2O7具有更好的隔热性能.并讨论了涂层显微组织对涂层隔热性能的影响. 相似文献
7.
碳化铬基自润滑耐磨涂层材料的制备及表征 总被引:1,自引:0,他引:1
采用碳化铬、镍铬合金、氟化物共晶体和银的复合粉末为原料,通过等离子体喷涂方法制备高温耐磨自润滑涂层。利用扫描电子显微镜对粉末材料和涂层的微观组织结构进行分析,并对其摩擦性能分析、研究。结果表明:分别采用镍铬合金润湿碳化铬、银包覆氟化物共晶体的方法有效的降低了等离子体喷涂过程中的脱碳、烧损问题。与国外相同材料组分的碳化铬基自润滑涂层相比,涂层具有孔隙率低、自润滑组分(氟化物、银)分布均匀、摩擦系数为0.18~0.20等特点。 相似文献
8.
9.
NiAl复合材料热喷涂涂层可以作为陶瓷涂层的粘结底层和抗氧化面层。采用蒸发冷凝方法制备了平均粒度为80 nm的铝粉。把纳米铝粉作为外包覆材料得到铝包镍复合粉末。SAXS检测纳米铝粉的粒度,SEM、HRTEM、TG-DSC检测了纳米铝粉、复合粉末和涂层的结构。表明纳米铝粉包覆材料成分均匀、包覆完整,熔化反应温度更低,放出较多的热量。制备的涂层致密、均匀,为典型的层状结构,与基体的结合强度好。 相似文献
10.
11.
Y2O3部分稳定的ZrO2(YPSZ)陶瓷涂层与高温合金基体间的特性差异较大,极易产生高的残余应力从而导致涂层脱落失效。为此,本文通过ANSYS有限元模拟方法对热喷涂YPSZ陶瓷涂层的温度场和残余应力进行了研究,结果表明:热喷涂过程中,YPSZ熔滴以一定速度在无限大MCrAlY合金表面沉积后,其温度场呈梯度分布;发生散流变形的同时与底层有热交换作用,最终凝固成圆片状固体颗粒;2000μs左右,YPSZ颗粒与底层的温度趋于一致,此时,熔滴中心轴线上的径向应力呈几乎线性分布,而轴向应力则呈非对称的近抛物线型分布;残余应力的极大与极小值都出现在边缘附近。 相似文献
12.
Klaus Fritscher Wolfgang Braue Uwe Schulz 《Metallurgical and Materials Transactions A》2013,44(5):2070-2082
The chemical composition of the alumina-zirconia mixed zone (MZ) of an electron beam physical vapor deposited thermal barrier coating (EB-PVD TBC) system is affected by service conditions and by the interdiffusion of elements from the substrate alloy below and the zirconia top coat. Three NiCoCrAlY bond-coated Ni-base substrates with YPSZ or CeSZ EB-PVD TBCs were subjected to a cyclic furnace oxidation test (FCT) at 1373 K (1100 °C) in order to provide experimental evidence of a link between chemistry of the MZ, the substrate alloy, the ceramic top coat, and the time in the FCT. Energy dispersive spectroscopy of the MZ revealed preferred accumulation of Cr, Zr, Y, and Ce. The concentration of the reactive elements (RE = Ce + Y + Zr) was related to the respective average lifetimes of the TBC systems at 1373 K (1100 °C). The RE content in the MZ turned out to be a life-limiting parameter for YPSZ and CeSZ TBC systems which can be utilized to predict their relative lifetimes on the individual substrates. Conversely, the TBC failure mechanisms of YPSZ and CeSZ TBC systems are dissimilar. 相似文献
13.
纳米颗粒增强铜基复合材料的最新研究动态及发展趋势 总被引:7,自引:0,他引:7
纳米颗粒增强铜基复合材料具有独特的结构特征、优异的力学性能,与纯铜近似的导电、导热性能,是一种有着广泛应用领域的功能材料。综述了纳米颗粒增强相的类型及选用原则,论述了纳米颗粒增强铜基复合材料的制备方法以及颗粒增强相的类型、颗粒增强相的含量、制备工艺三方面对复合材料性能的影响,并对将来材料的研究方向进行了展望。 相似文献
14.
为了研制一种连铸结晶器耐高温耐磨材料,采用超音速等离子喷涂法在纯铜板上制备了氧化钇部分稳定的氧化锆(YPSZ)涂层.利用X射线衍射仪、扫描电镜、彩色3D激光显微镜和图形软件(Image-pro Plus3.0)对YPSZ涂层的微观组织进行表征,通过销盘式磨损仪在室温干摩擦条件下测试了涂层的耐磨性能及化学硬化对涂层耐磨性能的影响.研究发现YPSZ涂层完全由t’-ZrO2相组成,其断口形貌由柱状晶和一定量的部分熔融颗粒组成,截面组织形态表现出较好的完整性,涂层孔隙率为1.2%,表面粗糙度为6.457μm.磨损实验表明化学硬化前YPSZ涂层与刚玉球对磨时的摩擦因数在0.5~0.6之间,平均磨痕宽度为3638.8μm,磨损体积为1.25508×10-2mm3,磨损机制为脆性断裂导致的磨粒磨损;化学硬化后YPSZ涂层的磨痕宽度和磨损体积均有大幅降低,脆断程度也更轻,其磨损性能得到极大改善. 相似文献
15.
温压致密化机理及其在温压粉末设计中的应用 总被引:13,自引:4,他引:9
温压是一项以较低的成本制造高性能铁基粉末冶金零部件的新型成形技术.实验发现,颗粒重排是温压过程的主导致密化机理,而为颗粒重排提供协调性的塑性变形是另一重要的致密化机理.作者分析了影响这2个致密化机理的主要因素.在此基础上,提出了温压粉末原料的设计原则,并成功设计了高性能。低成本合金钢粉末的3大体系温压粉末原料. 相似文献
16.
M. I. Natorkhin A. P. Garshin A. V. Bobyl’ V. N. Naraev D. V. Agafomov R. V. Sibiryakov 《Russian Journal of Non-Ferrous Metals》2014,55(3):238-241
Methods of preparation and results of investigation into high-porous spongy silver and the morphology of its formation are presented. It is shown that this product is a nanostructure consisting of silver particles 100–200 nm in size, which accreted with each other into branched conglomerates. Examples of using nanostructured highly porous spongy silver are presented. 相似文献
17.
18.
B. N. Putimtsev 《Powder Metallurgy and Metal Ceramics》1968,7(11):839-844
Conclusions The results are presented of an investigation into the influence of melting technique, melt composition, and the atomizing medium on the fabricating and physical properties of powders with spherical, compact particles. Characteristic features of the disintegration of metallic melts and of the shaping and oxidation of particles in the air and nitrogen atomization of the melt stream are examined. The desirability is demonstrated of deoxidizing metals and alloys by diffusion in the melting process and employing inert atomizing media to obtain oxide free powders of ferromagnetic metals and alloys. On the basis of this investigation, recommendations are given for the production of high quality ferromagnetic powders for use in electrical apparatus.Translated from Poroshkovaya Metallurgiya, No. 11(71),pp. 1–7, November, 1968. 相似文献
19.
CA Mirkin RL Letsinger RC Mucic JJ Storhoff 《Canadian Metallurgical Quarterly》1996,382(6592):607-609
Colloidal particles of metals and semiconductors have potentially useful optical, optoelectronic and material properties that derive from their small (nanoscopic) size. These properties might lead to applications including chemical sensors, spectroscopic enhancers, quantum dot and nanostructure fabrication, and microimaging methods. A great deal of control can now be exercised over the chemical composition, size and polydispersity of colloidal particles, and many methods have been developed for assembling them into useful aggregates and materials. Here we describe a method for assembling colloidal gold nanoparticles rationally and reversibly into macroscopic aggregates. The method involves attaching to the surfaces of two batches of 13-nm gold particles non-complementary DNA oligonucleotides capped with thiol groups, which bind to gold. When we add to the solution an oligonucleotide duplex with 'sticky ends' that are complementary to the two grafted sequences, the nanoparticles self-assemble into aggregates. This assembly process can be reversed by thermal denaturation. This strategy should now make it possible to tailor the optical, electronic and structural properties of the colloidal aggregates by using the specificity of DNA interactions to direct the interactions between particles of different size and composition. 相似文献
20.
Takuya Tamura Yuuki Maehara Naoki Omura Kenji Miwa 《Metallurgical and Materials Transactions A》2008,39(8):1917-1921
The method for producing Mg-Cu-Y and Fe-Co-B-Si-Nb bulk metallic glasses using electromagnetic vibrations is effective in
forming the metallic glass phase. Disappearance or decrement of clusters by the electromagnetic vibrations applied to the
liquid state is considered to cause suppression of crystal nucleation, because the electromagnetic vibrations vibrate the
clusters vigorously in the melt. The purpose of this study was to investigate motion of the crystal particles by the electromagnetic
vibrations in Mg-Cu-Y bulk metallic glasses. The electromagnetic vibration force vibrated the crystal particles or the clusters
that become crystal nuclei in the melt, because the electric current for the electromagnetic vibrations concentrates in those.
Thus, the electromagnetic vibrations were found to select vibration particles from the melt. Moreover, it was considered that
composites for which second phases or other compounds are dispersed into the metallic glass phase or a nanostructure phase
can be produced by the electromagnetic vibration process.
This article is based on a presentation given in the symposium entitled “Bulk Metallic Glasses IV,” which occurred February
25–March 1, 2007 during the TMS Annual Meeting in Orlando, Florida under the auspices of the TMS/ASM Mechanical Behavior of
Materials Committee. 相似文献