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耐磨材料分为三大类:金属和合金、陶瓷和陶瓷复合材料、塑料类(主要是合成橡胶和聚氨基甲酸酯的复合材料)。后者可制成整体构件或喷涂成防护层。这三类材料可以复合使用,如钢—橡胶、陶瓷—金属和橡胶—陶瓷复合材料。许多耐磨材料已大量制成专用产品系列,如筛面、球磨机衬板和砂泵部件。下面就耐磨材料的耐磨性进行一般性的讨论。 相似文献
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采用粉末注射成形工艺成形了SiCP/Cu复合材料,再采用溶剂脱脂、热脱脂和烧结的工艺制备了复合材料试样。研究了成形过程中复合材料显微组织的变化,并研究了烧结后的显微组织、力学性能、磨损性能。研究结果表明:SiCP/Cu复合材料在1050°C且在H2保护下烧结状况良好;复合材料的抗拉强度取决于SiC颗粒的体积分数以及其在基体中的分布状况;SiC含量为5vol.%和10vol.%,微裂纹萌生于SiC颗粒与基体的界面处;SiC含量为15vol.%,微裂纹萌生于SiC颗粒与基体。SiC体积分数为5%、10%、15%的SiCP/Cu复合材料的抗拉强度分别为254MPa、 291 MPa和278MPa。复合材料的力学性能随SiC含量的升高先升高后降低,而其磨损性能随SiC含量的增加而增加。 相似文献
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微观结构和孔隙参数对于SiC多孔陶瓷管的过滤性能至关重要,采用压汞法和X射线衍射法对使用前后的多孔陶瓷管孔径变化进行了量化研究。通过水淬法对SiC多孔陶瓷管的抗热震性进行了评估,利用扫描电子显微镜(SEM)、能谱分析(EDS)等手段分析了SiC多孔陶瓷管的表面形貌、微观结构和物相组成。结果表明,SiC多孔陶瓷管结构均匀,膜表面形貌粗糙复杂,适用于微米级过滤。在200~250℃的工作温度下,SiC多孔陶瓷管的抗弯强度保持率在75%以上。在冶金烟气除尘过程中,粒径小于膜孔径的SiO2和Fe杂质会穿过膜层进入到支撑体层,在支撑体孔隙表面吸附沉积,使其孔径减小28.8%左右;膜层表现良好的稳定性,不会被污染。 相似文献
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SiCf/SiC陶瓷基复合材料是未来航空发动机重要材料之一,其表面涂层是保护SiCf/SiC陶瓷基复合材料关键技术。针对陶瓷基复材表面的Sc2O3-Y2O3-ZrO2基可磨耗涂层与EBC涂层结合力不够高、应力匹配性差等问题,开展Sc2O3-Y2O3-ZrO2基梯度可磨耗涂层设计、制备与考核技术研究,并且与非梯度可磨耗涂层进行性能对比。研究结果表明:梯度可磨耗涂层比非梯度可磨耗涂层结合强度提高了6.7%;在(1 250±50)℃高温冲击1 000次后,梯度可磨耗涂层剥落面积仅为非梯度可磨耗涂层剥落面积的1/6。因此,梯度可磨耗涂层具有更好的力学性能,有望在未来航空发动机中得到广泛应用。 相似文献
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螺旋叶片是截齿的载体,也是滚筒采煤机的关键部位,因此叶片制造的精度直接影响滚筒的性能。螺旋叶片成形胎具的设计制造对叶片的制造质量有至关重要的影响。以辽源煤机厂现场实际加工螺旋叶片的数据为依据,在用计算法进行螺旋叶片的下料计算后,利用Unigraphics对螺旋叶片辗压过程进行建模,并用3DS MAX进行动态模拟螺旋叶片的辗压过程。 相似文献
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螺旋叶片的几种成形方法 总被引:3,自引:2,他引:1
螺旋叶片是螺旋机械的基本构件,由于它具有特殊的空间曲面形状,因而加工制造困难。介绍了螺旋叶片的几种成形方法,并对每种成形方法的优、缺点进行了分析,为螺旋叶片的加工提供参考。 相似文献
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在多重地质条件下,既要使掘进安全快速,又要使帮壁周边爆破成形,不致其严重破坏失稳,而且使单循环利用率高。本文利用改进的支护方法结合控制爆破原理对特殊岩层的支护方案,布眼规格、装药结构适当调整,达到了理想效果,为鸡笼山金矿探建工程施工安全快速优质通过复杂松软岩层创出了一条新路。 相似文献
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以碳化硅纤维为纤维增强剂,纳米级碳化钛为粒子增强剂,氮化硅粉末为基体,制备Si_3N_4/SiC_w/TiC_p系纳米复合陶瓷刀具材料。采用XRD和SEM分别表征复合氮化硅烧结体的组成和表面微观形貌。采用三点弯曲法,用PSD-5TSJTH型万能试验机测量样品的密度和抗弯强度。对于制备的Si_3N_4/SiC_w/TiC_p系纳米复合陶瓷刀具材料进行断续切削试验和连续切削试验。结果表明,制备的Si_3N_4/SiC_w/TiC_p系纳米复合陶瓷刀具的断裂韧性最高达9.5 MPa·m0.5,抗弯强度达780 MPa,显著地超过一般氧化铝陶瓷切削刀具材料的韧性值。断续切削时刀具的寿命比氧化铝陶瓷刀具更长1.6~15倍,连续切削时也具有良好的耐磨性能。 相似文献
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The current study involves a novel approach to measure froth rheology in-situ using vane. The results showed that the horizontal flow of froth towards the flotation launder interferes with the rheology measurement. A tube encircling the vane was used to minimize the effects of the horizontal flow. In order to convert the rheology raw data to rheograms, shear stress is only a function of the vane geometry and the torque values. However, it was shown that calculation of the shear rate from the vane speed depends on whether froth is fully or partially sheared.The froth characterised in this study exhibited a pseudo-plastic nature with a minor yield stress using Casson model. Therefore, froth viscosity which potentially affects froth transportation is not constant throughout the whole froth phase and it depends on the local shear rate. The suitability of the vane system to measure rheology of fluids with low shear stress was examined using a Newtonian silicone oil. It was found that the vane head should not be run in speeds above a certain range which needs to be determined. Measurements above such a speed range may not be accurate. 相似文献
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We have fabricated the large single domain YBaCuO bulk superconductors by using multiseeding technique combined with composition gradient in the precursor. Obviously, the growth time can be shortened by multiseeding method and the weak links between grain boundaries originated from different seeds can be also overcome with introducing the chemical component gradient and arranging the seeds exactly. For these YBCO disks, only single peak occurs in the distributions of trapped field, and the magnetic levitation force is equal to that of the same size sample fabricated with single seed. Although the arrangement of seeds is similar, the distribution of trapped field still shows four peaks for the sample without composition gradient. 相似文献
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1 IntroductionIt is known that a top-seeded melt-growth method (TSMG) allows the growth of c-axis oriented RE-BaCuO bulk superconductors[1]. Large single domain YBCO bulk superconductors exhibit excellent fieldtrapping properties . A single domain sample of 10 cm diameter is now available from TSMG process[2].However ,a processing ti me is too long due to the lowgrowth rate of Y123 grainin a peritectic melt ,andregarded as one of the most significant weak points in general .For example… 相似文献
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JIAO Yu-lei XIAO Ling ZHENG Ming-hui 《材料研究与应用》2005,(3):196-200
We have fabricated the large single domain YBaCuO bulk superconductors by using multiseeding technique combined with composition gradient in the precursor. Obviously, the growth time can be shortened by multiseeding method and the weak links between grain boundaries originated from different seeds can be also overcome with introducing the chemical component gradient and arranging the seeds exactly. For these YBCO disks, only single peak occurs in the distributions of trapped field, and the magnetic levitation force is equal to that of the same size sample fabricated with single seed. Although the arrangement of seeds is similar, the distribution of trapped field still shows four peaks for the sample without composition gradient. 相似文献