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《特种铸造及有色合金》2021,(10)
正近日,由包头金山磁材有限公司研发的高频稀土永磁电机用高性能低涡流烧结钕铁硼磁钢制造技术获得突破。项目采用多合金技术,不同合金根据特性分别进行成分、氧含量及组织结构控制,使磁体保持低的电导率,同时有较好的富钕相分布及优良的显微组织结构;磁体后加工采用特定单元划分与组合,局部采用高温固化绝缘胶粘接处理,使磁体高频工况时发热降低。在成形工艺上,采用异形产品一次成形工艺,减少投料比,减少后加工程序及人员投入,降低生产制造成本。项目的实施,既改善了高频应用领域磁体涡流发热高的问题,同时磁体综合磁性能大于74,也是高磁能积、高矫顽力双高磁体在性能方面的一次突破。 相似文献
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采用温压工艺制备了钕铁硼粘结磁体,研究了温压压力、温压温度、粘结剂种类及含量对磁体磁性能的影响,以及温压工艺对钕铁硼粘结磁体氧含量的影响.利用Nd2Fe14B/a-Fe系双相纳米晶磁粉为原料,在200℃下,采用12MPa的压力,获得性能最佳的磁体,其密度为6.43 g/cm3,磁性能为:Br=0.808 T,Hcb=461 kA/m,Hci=623 kA/m,(BH)max=101 kJ/m3. 相似文献
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粘结永磁体的工艺技术所说的粘结磁体是指以永磁粉末和粘结剂混合物为原料按确定的工艺制成的磁体。永磁粉末可以是铁氧体、钕铁硼、钐钴、铝镍钴或者是它们的混合物。由于工艺的发展,粉末的性能不断地提高,如由Mag-nequench开发的熔体快淬钕铁硼粉末几乎都... 相似文献
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目的探究军用车辆有机涂层在全浸泡条件下的腐蚀行为特征,寻找评价涂层腐蚀防护性能的有效方法。方法利用电化学阻谱技术,对某型军用灰色涂层在全浸泡条件下的腐蚀行为进行了研究,分析了其阻抗谱及低频阻抗模值0.1 Hz|Z|、高频相位角10 k Hzq、相对介电常数re三种特征参数的变化规律。以三种特征参数作为评价指标,利用SOFM自组织神经网络对涂层性能的变化过程进行研究。结果灰色涂层在全浸泡下的腐蚀过程大致经历三个阶段。良好阶段:高频相位角q位于70°附近,低频阻抗模值|Z|均大于10~7。防护性能下降但仍具有保护作用阶段:高频相位角q下降至50°附近,低频阻抗模值|Z|下降至10~6附近。防护性能丧失阶段:高频相位角q全部低于50°,低频阻抗模值|Z|已经低于10~5。SOFM自组织神经网络对涂层的分类结果与对阻抗谱特征分析的结果保持一致。结论通过实例分析,证明自组织神经网络SOFM方法可实现对涂层性能状态的快速判断。 相似文献
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Thick-layer coating systems in corrosion protection Thick-layer coating systems represent a novel method of applying coatings for corrosion protection. Different varieties are available, depending on the conditions to which the object is exposed. Through a special combination of rheological properties between thixotropy and structure viscosity, it is possible to obtain great dry-layer thicknesses in one go. Advantages: The need for individual coating operations is obtiated; greater overall thickness can be obtained; better cover for edges and rivet heads; more rapid application; better corrosion protection. Using the unit construction method, the thick-layer coating systems can also be built into conventional systems, depending on individual requirements. 相似文献
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目的 探索电极的梯度多孔结构对碱式电解水析氢性能的影响。方法 采用大气等离子喷涂工艺制备不同Al含量的涂层,经化学腐蚀后,得到单一多孔电极和梯度多孔电极。通过SEM/EDS、XPS、XRD和工业CT对样品微观形貌、元素价态、物相等进行表征和分析,采用线性扫描伏安法(LSV)、循环扫描伏安法(CV)和电化学阻抗谱法(EIS)等手段研究样品的析氢性能。结果 通过控制Al的添加量,可以有效控制涂层的孔隙率。通过多组粉末的配合喷涂,成功实现了梯度多孔结构的制备。所制备样品的析氢Tafel斜率都接近于120 mV/dec,其析氢速率控制步骤皆为Volmer过程,即水分子吸附和解离过程。N30A表面最平整,表现出最接近电容的阻抗特性,其电解性能也因此最差;N40A表现出与N50A类似的阻抗特性,但其整体孔隙率较低,因此其电解性能较差;低电流密度下,N50A和N543A表现出十分接近的电解性能,而高电流密度下N543A表现出更加优越的电解性能。结论 梯度多孔结构的引入可以促进电解液的输运,同时提供较好的排气能力,又能保证足够的反应活性位点,因此可以有效提升析氢性能。 相似文献
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Slurry‐derived coatings are an interesting alternative method to pack aluminization of nickel‐base superalloys, which provide similar properties and protection at high temperatures. For highest performance, these aluminide coatings are modified by the addition of Pt or, as recent research suggests, with Pt/Ir. While the combination of Pt and Pt/Ir with an out‐of‐pack process is state of the art, slurry coatings are of special interest as a repair method for turbine blades. In this study, the microstructural evolution of slurry‐derived coatings manufactured on CM 247 in inert atmosphere as well as in air was investigated. Layers of Ni, Pt, and Pt/Ir mixtures were electrodeposited. After annealing, a diffusion heat‐treatment with a slurry containing aluminum or aluminum–silicon powder was applied on the samples. The addition of silicon is well known to be beneficial for hot corrosion environments. The reaction and interdiffusion behavior of aluminum/aluminum–silicon determines the microstructural evolution of the coatings. Depending on the initial electroplated layer on the surface, different microstructures can be obtained, such as the Pt/Ir‐modified beta phase (Ni,Pt)Al or two‐phase layers of PtAl2 and NiAl. Additionally, the reactivity between the elements at the surface and those from the slurry was shown to determine homogeneity and surface roughness of the diffusion coating, also depending on the atmosphere used during slurry aluminization. Finally, it was demonstrated that iridium has a high influence on the diffusion behavior and especially the distribution of platinum in the coatings. Such new coatings have the potential to overcome some disadvantages of conventionally manufactured high‐activity aluminide coatings, as the combination of Pt/Ir‐electroplating with the slurry process results in less detrimental substrate elements like molybdenum or tungsten close to the surface. 相似文献
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Wear-Resistant Amorphous Iron-Based Flame-Sprayed Coatings 总被引:1,自引:0,他引:1
J. Voyer 《Journal of Thermal Spray Technology》2010,19(5):1013-1023
The flame-spraying process (powder and wire) was used to spray Nanosteel SHS-7170 powder and Eutectic-Castolin EnDOtec DO-390N
wire onto aluminum and mild steel substrates to produce partially amorphous iron-based coatings. The phase content and the
wear resistance of the coatings were evaluated in the as-sprayed condition only. The results obtained showed that the powder
and wire flame iron-based coatings performed relatively well in terms of wear resistance. The coating microstructure, phase
content, hardness, and wear performance all depended strongly on the spraying parameters used. This study showed that amorphous
iron-based coatings with good wear resistance could be produced using the flame-spray process, showing that this process appeared
to be a suitable inexpensive alternative to plasma or high velocity oxygen-fuel spraying processes. 相似文献
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Ways of protection of identification marks obtained by the electrodischarge method on the basis of the Cartesian, spectral, and phase picture approaches have been offered. It has been shown that a sufficiently reliable level of protection can be attained at a mark processing time duration on the order of five seconds. 相似文献
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目的提高(SiC)P的吸波性能。方法采用低成本、环保型的化学镀镍方法对(SiC)P表面进行修饰,设计了氧化、亲水、敏化、活化系列增强前处理工艺,确定了(SiC)P表面修饰的最佳工艺流程。用SEM、EDS、XRD等分别表征了修饰前后(SiC)P形貌、成分、物相的改变,采用波导法测定了修饰后碳化硅复合粉体的介电性能,并以其为吸波剂在铝板上制备了吸波材料。结果修饰后,获得了镀层连续、无光滑(SiC)P裸露的较高质量的碳化硅复合粉体(简写为(Ni/SiC)P)。(Ni/SiC)P较原粉(SiC)P,其形貌、组成、结构发生了明显改变,且介电常数、介电损耗、吸波性能明显增强,其中,介电常数的实部增强约为22%,虚部增强约为20%。涂覆1层(Ni/SiC)P涂料,在17.12 GHz时,RL=−15.47 dB,大于涂敷2层原粉(SiC)P涂料的吸收效果。涂覆2层(Ni/SiC)P涂料,在16.11 GHz时,RL=−23.51 dB。结论采用低成本、环保型方法实现了(SiC)P表面高质量修饰,修饰后,复合颗粒(Ni/SiC)P的介电性能及吸波性能均明显提高。 相似文献