共查询到19条相似文献,搜索用时 78 毫秒
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用炭毡作为纤维增强体,采用多元耦合物理场CVI工艺,在自行设计的CVI炉中增密C/C复合材料,对CVI沉积条件(温度、压力、气体流速、毡体密度、碳源)和石墨化热处理温度对C/C复合材料XRD结构参数(石墨化度g和石墨微晶尺寸Lc)的影响进行了研究。结果表明,采用本工艺制备C/C复合材料,经过工艺优化,材料经过2300℃、2h的石墨化处理,其石墨化度可达到77%以上;并且发现,较高的沉积温度、较低的压力、较大的气流速度、较大密度的毡体有利于C/C复合材料晶体有序度的提高;其次,采用石油液化气(LPG)作碳源时样品的晶体有序度比丙稀(GH6)作碳源时稍高;石墨化热处理可进一步提高材料的石墨化度,升高的幅度和组织结构密切相关,提高材料石墨化度的关键环节是CVI工艺条件。 相似文献
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C/C复合材料抗氧化复合涂层制备及其性能 总被引:3,自引:0,他引:3
设计并制备出了一种C/ C复合材料抗氧化涂层, 其基本结构为浸渍过渡层/ 陶瓷相阻挡层/ 玻璃相封填层。涂覆有复合涂层的C/C 复合材料试样在空气中于900 ℃下氧化10 h的失重率仅为0.034 g/cm2, 氧化失重速率为5.67×10-5 g/(cm2·min);900 ℃ 室温空气中急冷急热10 h循环100次后, 失重率为8.41%, 涂层没有剥落, 说明整个涂层具有良好的高温抗氧化性和抗热震性能。这种复合涂层可在中低温(不大于1 100 ℃)氧化性气氛中长时间工作, 适合作C/C复合材料航空刹车副等部件的抗氧化涂层, 能够大大提高C/ C复合材料的使用寿命和性能。 相似文献
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采用超声搅拌铸造法制备SiC/A356复合材料,研究颗粒含量、载荷、转速对材料耐磨性的影响。结果表明,SiC/A356复合材料耐磨性显著优于基体,8%SiC/A356复合材料的耐磨性最好,是基体材料的2倍。SiC/A356和基体两种材料的磨损率均随着载荷和转速的增加而增大,其中基体的磨损率变化较为明显,但两种材料转速的磨损率曲线斜率远小于载荷对其的影响。在稳定摩擦磨损阶段,复合材料的摩擦因数大于基体合金材料。 相似文献
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深层搅拌桩搅拌头结构和动力特性对桩体搅拌均匀性的影响 总被引:2,自引:1,他引:1
李旭庆 《探矿工程(岩土钻掘工程)》2009,36(9):56-58
通过对搅拌头叶片的动力特性和切削搅拌机理分析,阐明影响桩体搅拌均匀性的主要因素是叶片的水平旋转速度和垂直运动速度,分析了搅拌头结构形式对搅拌均匀性的影响,提出了提高搅拌均匀性的途径. 相似文献
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采用超声搅拌铸造法制备了SiC/A356复合材料,研究了颗粒含量、不同载荷、不同转速对材料耐磨性的影响。实验结果表明,SiC/A356复合材料耐磨性显著优于基体,8vol%SiC/A356复合材料的耐磨性最好是基体材料的2倍;SiC/A356和基体两种材料的磨损率均随着载荷和转速的增加而增大,其中基体的磨损率变化较为明显,但两种材料转速的磨损率曲线斜率远小于载荷对其的影响;在稳定摩擦磨损阶段,复合材料的摩擦系数大于基体合金材料。 相似文献
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以Ag-Cu-Ti合金为钎料钎焊连接C/C复合材料与钛合金(TC4),通过SEM对钎焊连接接头的微观组织和形貌进行分析,用EDS和XRD分析接头中的元素分布和物相组成.实验结果表明,中间钎料层与TC4合金之间的界面,形成了良好的界面扩散层,厚度为5~7μm,与TC4钛合金连接侧的钎料相组成主要为CuTi2,CuTi和Cu3 Ti2;钎料层与C/C复合材料形成的扩散层厚度为1~3 μm,与C/C复合材料连接侧的钎料相组成主要为CuTi2和CuTi.C/C复合材料与TC4合金之间形成了冶金结合. 相似文献
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V. A. Chanturia I. Zh. Bunin M. V. Ryazantseva I. V. Filippova E. V. Koporulina 《Journal of Mining Science》2011,47(4):506-513
The X-ray photoelectronic spectroscopy data give the grounds for statement that the powerful nanosecond electromagnetic pulse pretreatment improves sorption activity of pyrite surface and lowers sorption of a collector at arsenopyrite surface. The research results are verified by test data on the powerful nanosecond electromagnetic pulse effect on the structure and chemical properties of pyrite and arsenopyrite surface, as well as their electrochemical and flotation properties. 相似文献
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Some physical and chemical properties of three ilmenite samples: IL-F (purchased from the mineral dealership of A and F Krantz), IL-Q (Qara-aghaj deposit, Iran) and IL-K (Kahnuj deposit, Iran) were studied. The substitution of different amounts of Mg, Mn and V in the crystal structure of ilmenite was identified by microprobe analysis. Different amounts of hemoilmenite exsolution were observed inside all three ilmenite samples using SEM, electron microprobe and X-ray diffraction analysis. Using these analytical techniques, titanite phase was found inside the IL-K ilmenite. The XPS analysis indicated that the contents of Fe3+ are 5.66, 5.33 and 3.72% for IL-F, IL-Q and IL-K, respectively which are in good agreement with the amounts of hemoilmenite exsolution. Mg and V contents in the ilmenite crystal structure have a good negative correlation with lattice constants (LC), unit cell volume, crystallinity index, specific gravity and IEP, while the Mn content correlates positively with these parameters. The IEP determined as 4.2, 5.4 and 6.25 for IL-F, IL-Q and IL-K, respectively, has a negative correlation with Fe3+ ions and ilmenite floatability. In comparison with magnetic susceptibility, the electrical resistivity of ilmenite has a higher correlation with surface properties (IEP and floatability), lattice constants, and unit cell volume. 相似文献
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V. A. Chanturia I. Zh. Bunin M. V. Ryazantseva I. A. Khabarova 《Journal of Mining Science》2012,48(4):732-740
The mechanism for the powerful nanosecond electromagnetic pulse (MNEMP) effect on the phase composition of new-formed chalcopyrite and sphalerite structures is studied by IR Fourier spectroscopy method. The authors establish the effect of the higher sorption activity of sulfide minerals subjected to the electromagnetic pulse treatment. The research data are confirmed by the experimental data on MNEMP effect on electrochemical and flotation properties of chalcopyrite and sphalerite. 相似文献
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针对微机保护测控装置在电磁操动机构中使用时易烧合闸线圈的问题,提出了对其控制回路的改进方法,该方法投资较小,实施简单,效果明显. 相似文献
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The present investigation concerns influence of high power nanosecond electromagnetic pulses on thermoelectric properties,
conduction and electrode potential of pyrite and arsenopyrite, Darasunskoe deposit. Experimental data obtained are in full
compliance with classical concepts on interrelation between electrochemical and flotation properties of minerals. 相似文献
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采用电磁搅拌连续铸挤技术生产Al-5Ti-1B合金晶粒细化剂,研究了Al-5Ti-1B合金的化学成分、显微组织和晶粒细化效果,并与美国KBA、荷兰KBM、英国LSM 公司生产的Al-5Ti-1B合金进行了比较,对电磁搅拌连续铸挤Al-5Ti-1B合金的质量进行了评价.结果表明:电磁搅拌连续铸挤Al-5Ti-1B合金中Ti和B元素含量分别为5.08,和1.02,.Fe ,Si及V杂质元素含量分别为0.11,,0.087,和0.011,;T iA l3相呈块状,平均尺寸为15.7μm ,而T iB2粒子呈颗粒状均匀分布于α-A l基体,平均尺寸为0.74μm ;添加0.2,的A l-5 T i-1B合金,可使纯铝晶粒平均尺寸从2800μm细化到68μm .比较结果表明:电磁搅拌连续铸挤A l-5 T i-1B合金的元素含量更稳定、杂质元素含量更低,T iA l3相和T iB2粒子更细小均匀,对铝晶粒的细化能力更强. 相似文献