共查询到19条相似文献,搜索用时 78 毫秒
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研究了氢爆工艺(HD)对烧结NdFeAlB的微观结构与永磁性能的影响。用HD工艺制备的NdFeAlB烧结磁体(HD磁体)的矫顽力比传统球磨(BM)工艺的高,但剩磁及磁能积较低,介绍和评述了磁性合金的氢爆(HD)对气流磨(JM)的影响并强调磁粉粒度、粒度分布、粒度均匀性对制备高性能磁体的重要性。 相似文献
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本文在分析烧结NdFeB取向度的各种计算方法的基础上,提出一种新的计算方法。采用这种方法,仅利用烧结体垂直于外加磁场方向截面的X射线衍射谱,通过简单的计算就能很容易的计算出磁体的取向度。 相似文献
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对电化学充氢后的2.25Cr-1Mo钢进行拉伸实验,并在实时拉伸过程中采集声发射信号。结果表明:充氢后2.25Cr-1Mo钢抗拉强度为536.30MPa,下降约57MPa;断面收缩率为43.62%,下降约7%。拉伸断口上出现由氢脆引起的"白点"特征与准解理断裂形貌。充氢后试样拉伸过程弹性阶段的声发射信号活动增强,而屈服阶段的声发射信号活动减弱,变形过程的声发射信号累积绝对能量值要比未充氢试样低约1个数量级。充氢试样拉伸产生的声发射信号比未充氢试样的信号幅值降低约0.33mV,频宽降低0.06MHz。通过对声发射信号的分析发现,充氢试样变形的微观机制为氢促进位错发射与运动,而交叉滑移受到抑制。 相似文献
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49条(1)作为定量包装商品的制造商他必须选择满足下述两项中的任何一项之规定———(a)按照相应的规定用合格的设备以适当的方式来制作定量包装商品;(b)按照下述(ⅰ)(ⅱ)的要求在规定的时间内针对所制造的定量包装商品选择检验足够的样品以证明其满足上述条款47(1)的要求———(ⅰ)用合格的设备以适当的方式来进行检验,(ⅱ)以适当的方式按规定时间保存足够检验的结果和原始记录。(2)作为定量包装商品的进口商他必须选择满足下述两项中的任何一项之规定———(a)按照上述条款(1)(b)之规定在规定的时间内对… 相似文献
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高佃飞 《中国新技术新产品》2013,(11):150-151
氢内冷汽轮发电机漏氢量的大小直接影响到机组的安全运行,它是汽轮发电机组运行的主要技术指标之一,所以对发电机漏氢量的控制就显得尤为重要。影响发电机漏氢量的因素很多,涉及到制造、安装、运行、检修等各个方面。本文主要结合本人的实际经验,重点介绍张家口发电厂发电机漏氢与治理的措施和具体实施情况,以及实际效果。 相似文献
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High-resolution field emission spectroscopy has been used to study the nanostructure of the NdFeB alloy. This revealed a fine
banded structure of the grain-boundary phase which is responsible for the high coercivity of the alloy.
Pis’ma Zh. Tekh. Fiz. 24, 36–40 (February 26, 1998) 相似文献
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T. Ohta S. Bouchigny J.-P. DidelezM. Fujiwara K. FukudaH. Kohri T. KunimatsuC. Morisaki S. OnoG. Rouillé M. TanakaK. Ueda M. UrakiM. Utsuro S.Y. Wang M. Yosoi 《Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment》2012,664(1):347-352
We have developed a new cryogenic distillation system to purify Hydrogen-Deuteride (HD) gas for polarized HD targets in LEPS experiments at SPring-8. A small amount of ortho-H2 (∼0.01%) in the HD gas plays an important role in efficiently polarizing the HD target. Since there are 1-5% impurities of H2 and D2 in commercially available HD gases, it is necessary to purify the HD gas up to ∼99.99%. The distillation system is equipped with a cryogenic distillation unit filled with many small stainless steel cells called “Heli-pack”. The distillation unit consists of a condenser part, a rectification part, and a reboiler part. The unit is kept at the temperature of 17-21 K. The Heli-pack has a large surface area that makes a good contact between gases and liquids. An amount of 5.2 mol of commercial HD gas is fed into the distillation unit. Three trials were carried out to purify the HD gas by changing temperatures (17.5 K and 20.5 K) and gas extraction speeds (1.3 ml/min and 5.2 ml/min). The extracted gas was analyzed using a gas analyzer system combining a quadrupole mass spectrometer with a gas chromatograph. One mol of HD gas with a purity better than 99.99% has been successfully obtained for the first time. The effective NTP (Number of Theoretical Plates), which is an indication of the distillation performances, is obtained to be 37.2±0.6. This value is in good agreement with a designed value of 37.9. The HD target is expected to be efficiently polarized under a well-controlled condition by adding an optimal amount of ortho-H2 to the purified HD gas. 相似文献
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HDDR各向异性NdFeB温压混炼过程 总被引:1,自引:1,他引:1
研究了在HDDR各向异性NdFeB粘结磁体温压成形过程中粘结剂和润滑剂的添加量以及二者同磁粉的混炼工艺对磁体磁性能及机械强度的影响。利用B-H回线仪和扫描电子显微镜对磁体的磁特性和显微组织结构进行了分析测试,同时测试了不同工艺条件下处理的磁体的机械强度。结果表明,粘结剂的适量添加能够保证磁体同时具有较好的磁性能和机械强度。润滑剂的加入既降低了磁粉之间的摩擦力,又减小了磁粉在压制过程中的损伤度,从而使粘结磁体获得良好的磁粉填充率、磁取向度和磁性能。而粘结剂和润滑剂与磁粉之间的混炼方式决定了磁体中粘结剂的结合效果,从而决定了磁体最终的机械强度。采用合理的混炼工艺,可以使粘结磁体同时获得最佳的磁性能和机械强度。 相似文献
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新型熔炼工艺下GH4169合金的凝固组织控制研究 总被引:1,自引:1,他引:0
为探求新型熔炼工艺(三联)下GH4169合金大型重熔锭组织调控、元素偏析改善的方法,研究了熔速对氩气保护电渣重熔GH4169合金重熔锭枝晶间距、Laves相的尺寸及分布和显微疏松的影响,定量分析了熔速对组织与成分偏析的影响规律.研究发现:随着熔速的增加,GH4169合金重熔锭边缘处的枝晶间距基本保持不变;中心处二次枝晶间距呈增大趋势.边缘和中心处的疏松尺寸随熔速增加变化平缓,R/2处先增大后减小.心部的Laves相比例较高且随着熔速增加呈上升趋势,而R/2处趋势相反;重熔锭不同部位的偏析区比例随熔速无明显变化.枝晶间距越小,越有利于减轻偏析. 相似文献
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Yu. M. Pokotilo A. N. Petukh V. V. Litvinov V. P. Markevich A. R. Peaker N. V. Abrosimov 《Technical Physics Letters》2008,34(6):498-499
Shallow hydrogen donors (H-donors) were formed in a Ge1 − x
Si
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(x = 0.012) alloy by the implantation of low-energy protons followed by heat treatment at 275°C The electrical properties of
these donors have been studied using the method of capacitance-voltage characteristics. It is established that a certain fraction
of the H-donors exhibit bistability, whereby their concentration changes reversibly when the sample temperature is cycled
within 100–200°C. The properties of reversible H-donors in germanium are analogous to those of the bistable H-donors in silicon. 相似文献