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以石墨自润滑铜基粉末冶金材料/铬青铜和纯铜基粉末冶金材料/铬青铜为摩擦副,采用销-盘式载流高速摩擦磨损试验机对材料的摩擦学特性进行研究.结果表明,材料的磨损率随滑动速度的增大而减小,电流对摩擦副的摩擦学特性有显著的影响;相同条件下,石墨自润滑铜基粉末冶金材料/铬青铜摩擦副的摩擦系数和磨损率都明显小于纯铜基粉末冶金材料.无电流条件下,摩擦面上出现了明显的粘着痕迹,摩擦副的摩擦磨损机理主要为粘着磨损;在电场作用下,摩擦表面产生熔融孔洞和犁沟现象,磨损机理主要为电气磨损和磨粒磨损. 相似文献
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在销盘式"HST-100高速载流摩擦磨损试验机"上,对比考查了C/C复合材料与现役电力机车使用的浸金属碳滑板材料的抗电弧侵蚀性能.借助扫描电子显微镜(SEM)和X射线衍射仪(XRD)结合摩擦表面宏观温度的测量,研究了摩擦表面的物相组成与形貌.结果表明,随着速度的增加,两种材料的摩擦系数和磨损率都随之增加,但C/C复合材料的摩擦系数和磨损率均低于浸金属碳材料,且增加的趋势较小.C/C复合材料具有优异的摩擦学性能和载流质量,满足后续高速滑板材料的发展需要. 相似文献
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研究了三元层状化合物钛硅碳(Ti3SiC2)材料在载流滑动条件下的摩擦学特性.试验在盘一块式大功率载流高速摩擦试验机上进行,用A3钢盘作为对磨体;滑动速度为20~60 m/s,法向压强为0.4~0.8 MPa,电流强度为0,50和100 A.结果表明,在适当的速度和载荷条件下,Ti3SiC2陶瓷表现出良好的载流摩擦学特性.但载流条件下的摩擦系数和磨损率都比非载流条件下的大,且随电流强度的增大而增大.载流条件下,摩擦系数随法向压强和速度的增大而减小;磨损率随法向压强的增大呈下降趋势,随速度的增高而增大.SEM & XRD观察和分析结果表明,载流情况下Ti3SiC2摩擦面表层生成的TiC等硬质结晶相是导致摩擦系数增大的主要原因;而其磨损率增大主要由微电弧烧蚀与机械摩擦的交互作用及热-力耦合作用两部分共同影响所致.微电弧烧蚀作用引起Ti3SiC2表层氧化、熔融和分解,因而耐磨性发生改变. 相似文献
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任维佳 《稀有金属材料与工程》2016,45(8):2075-2079
采用粉末冶金法制备了不同SnO2含量的AgSnO2触头材料,研究了SnO2含量对AgSnO2触头材料电弧侵蚀行为的影响。采用扫描电子显微镜(SEM)表征了AgSnO2触头材料电弧侵蚀形貌,对影响AgSnO2触头材料电弧侵蚀的因素进行了分析。结果表明:在电弧侵蚀过程中侵蚀优先发生在SnO2区域。随SnO2含量增多,燃弧时间依次增加,侵蚀面积逐渐减小,侵蚀坑变深,金属喷溅增强。 相似文献
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采用渗硼烧结法合成了一种新型TiBN粉体材料,它兼有陶瓷性和金属性,电阻率为2.6×10-3Ω·cm。以TiBN和TiN为增强相,采用粉末冶金法制备了Cu/TiBN和Cu/TiN电接触材料,系统的研究了不同含量TiBN和TiN的电接触材料的微观结构和物理性能。结果表明,与TiN相比,TiBN增强相能明显改善Cu基电接触材料的导电性能、抗氧化性能、硬度和抗电弧侵蚀性能。当含量为5wt.%时,Cu/TiBN电接触材料的抗电弧侵蚀能力最好,重量损失仅为1.5mg。电弧侵蚀时,在Cu/TiBN表面生成TixOy、B2O3和N2等产物,这些产物能明显改善Cu/TiBN电接触材料的抗电弧侵蚀能力。新开发的Cu/TiBN电接触材料具有优异的物理性能和抗电弧侵蚀性能,在电接触行业中拥有广阔的应用前景。 相似文献
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采用粉末冶金法制备含不同质量分数ZnO的铜基复合材料,并对材料的密度、硬度和电导率进行考察.结果表明,与相同工艺制备的紫铜相比,复合材料的硬度有很大程度的提高,而电导率降低不明显.随着ZnO质量分数的增加,材料的密度和电导率都呈下降趋势,而硬度先增大后减小.当ZnO含量为10%时,复合材料具有最好的综合性能,密度达98%以上,HV硬度、电导率分别达980 MPa和41.5 MS/m. 相似文献
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针对机械摩擦多、噪声大的传统拉幅定型传送单元,提出一种新型的磁悬浮拉幅定型传送单元。磁悬浮拉幅定型传送单元作为新型的纺织机械传送单元,具有无机械摩擦、无噪声、污染少等优点。对新型传送单元滑动块材料进行选择,对比3种金属材料灰口铸铁、45号钢、Q235碳素结构钢。使用ANSYS分析电磁铁磁力在不同间隙下的变化,再利用ANSYS Workbench分析不同磁力下,3种材料传送单元滑动块的变形情况,判断其对传送单元悬浮气隙的影响。分析结果表明:悬浮气隙在0.005 mm以内,磁力误差在5%以内;Q235碳素结构钢比其余两种材料更适合做滑动块,并且降低了成本。 相似文献
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Mechanism of Degradation of Titanium Alloy IMI 834 and Its Protection Under Hot Corrosion Conditions
The excellent combination of high-temperature strength and lightweight properties makes titanium-base alloys attractive for high-temperature applications in aircraft engines. However, more hot corrosion of titanium alloys is a life-limiting factor, particularly when aircraft fly at low altitudes across the sea. In the present paper, an attempt has been made to understand the degradation mechanism of titanium alloy, IMI 834 under hot corrosion conditions at elevated temperatures. The hot corrosion studies were carried out by determining weight loss at different temperatures and in salts of pure Na2SO4, 90% Na2SO4+10% NaCl and 90% Na2SO4+5% NaCl+5% V2O5. Subsequently, the rate constants were evaluated. The depth of attack due to hot corrosion was compared with oxidation data. Finally, the degradation mechanism of the titanium alloy that leads to degradation of mechanical properties in aggressive environments has been discussed and suitable coatings suggested to enhance the operational life of engines by effectively preventing both oxidation and hot corrosion. 相似文献
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Thermogravimetry during cyclic oxidation of metallic alloys is described. A methodology is given in order to determine the Net Mass Gain, the Gross Mass Gain, the total mass of spalled oxide, the rate of metal consumption and the average oxide scale thickness as a function of the number of cycles. The fraction of oxide scale which spalls at each cycle can be also calculated, and the parabolic constant can be estimated at each cycle. Two examples are given: the cyclic oxidation of a NiAl single crystal in flowing oxygen at 1150°C, and the cyclic oxidation of alloy P91 at 800°C in laboratory air. Advantages and disadvantages of this technique are discussed in regards to classical interrupted tests in crucibles. Thermogravimetry during cyclic oxidation appears to be a powerful tool in order to model and quantify the cyclic oxidation test which is of great interest in order to qualify the resistance of materials to oxidation in conditions close to their actual use, but a specific aspparatus need to be developed in order to obtain data in an efficient and economical manner. A new apparatus designed for this purpose is described briefly. 相似文献
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《组合机床与自动化加工技术》2016,(2)
文章分析研究了滚动直线导轨副所受各类负载的特点,阐述了简单负载作用时,滑块的平均载荷与导轨寿命的传统计算方法;在此基础上,对多负载在实际工况中的常见性进行简要说明,进而提出在单一方向多负载同时作用、单一方向多负载逐段作用和多方向负载作用条件下平均载荷的等效算法。最后以龙门铣床为例,简述了铣床工作台及其导轨的运动特性,对滑块平均载荷及导轨寿命进行了计算说明。 相似文献
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Wright Roger N. Kircher Thomas A. Vervlied Jeff R. 《JOM Journal of the Minerals, Metals and Materials Society》1987,39(10):26-29
JOM - The bulk workability of a metal can be projected, or at least compared, using the tensile test analysis of Cockroft and Latham1,2 and the upset test analysis ofKuhn et al. 3−8 These two... 相似文献