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超细碳化钨-钴硬质合金的原子力显微镜研究 总被引:1,自引:0,他引:1
以液相复合-连续还原碳化方法制备的纳米碳化钨-钴复合粉末为原料,采用低压烧结制备了性能优良的超细碳化钨-钴硬质合金.运用原子力显微镜(AFM)对超细碳化钨-钴硬质合金的表面形貌进行了观察、缺陷和粒度分析,同时对合金的力学性能进行了测试.结果表明,采用低压烧结获得的烧结试样的洛氏硬度HRA≥93.5,抗弯强度TRS≥3300MPa,平均晶粒度<220nm.制备了具有高强度、高硬度的超细碳化钨-钴硬质合金.纳米碳化钨-钴复合粉末制备的超细硬质合金组织结构均匀,但局部仍然存在着组织缺陷,分析了产生缺陷的机理. 相似文献
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采用阳极弧放电等离子体方法制备了高纯银纳米粉末.利用X射线衍射(XRD)、透射电子显微镜(TEM)对样品的形貌、晶体结构、粒度进行性能表征.利用静态表面吸附仪依据BET多层吸附原理,在液氮温度下(78K)和气体饱和蒸气压力范围内测试样品对N2的吸附-脱附等温线,用图解法根据吸附等温线求出单层吸附容量,由BET吸附公式计算出纳米粉末比表面积.结果表明:银纳米粉末的晶体结构为fcc结构,粒径范围在10~50nm,平均粒径为26nm,比表面积为23.81 m2/g. 相似文献
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以乙二醇为分散剂,设计了正交实验考察纳米二氧化钛粉体在水中的分散性能,采用重力沉降法、分光光度法、粘度法、Zeta电位测定法、粒径分析等方法评价其分散效果。比较不同的表征手段的优劣及其适用的条件,寻求一种科学、准确、简易的表征二氧化钛粉体分散稳定性的方法。实验结果表明,分光光度法操作简便,对实验仪器要求不高,能快速表征体系的分散稳定性:结合Zeta电位测定和粒径分析,可以得到纳米二氧化钛分散稳定性的可靠信息。最后提出了纳米粉体分散研究的一般方法。 相似文献
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Hydrothermal extraction process of Co binder phase from WC-Co cermet was investigated in order to establish a novel recycling
system of WC-Co cermet scraps. When the cermet chips were hydrothermal-treated in hydrochloric acid above 110∘C, Co binding phase was efficiently extracted and the cermet chips were disintegrated into relatively large fragments. After
hydrothermal treatment, WC sintered body become very brittle and pulverized easily by ball milling and the mean particle size
of thus obtained WC particle became similar to that of virginal WC particle. The recycled WC powder was a little easier to
undergo oxidation than the virginal WC powder, so that the mechanical properties of recycled WC-Co cermets were degraded.
However, the degradation of mechanical properties was prevented only by drying the WC powder more carefully. This hydrothermal
process will be one of the recycling systems for WC-Co cermets. 相似文献
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《Advanced Powder Technology》2020,31(9):3824-3832
Cryo-milling of coarse micron grade elemental boron powder was investigated for possible generation of nanosized boron powder. Process parameters were optimized for the least contamination and least particle size. The as-milled powders were characterized by scanning and transmission electron microscopy (SEM/TEM) and x-ray diffraction (XRD) for powder morphology, average particle size, and phase analysis. The particle size and surface area were also estimated using dynamic laser scattering (DLS) and BET techniques to correlate with the performance of the material. Thermo-gravimetric and differential thermal analysis (TG-DTA) studies were performed to ascertain mass change and energy release in unmilled and milled powder. The average particle size of boron powder after 9 h of cryo-milling was<100 nm. The cryo-milled powder was made air-stable and dispersible in JP10 fuel by coating it with ligand through the mechanical milling method. The TOPO (tri-n-octyl phosphine oxide) coated nano boron powder exhibited dispersion stability for a week. 相似文献
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采用溶胶-凝胶法合成了不同粒径的Al2O3-30%(质量分数)TiO2纳米复合粉体,用喷雾干燥法对合成粉体进行喷雾造粒,造粒后的粉体通过等离子喷涂制备Al2O3/TiO2复合涂层,最后对涂层结构和性能进行了表征。涂层结构和形貌分析表明制备的涂层具有微米/纳米复合结构,初始粉体粒径对涂层的结构和致密度影响很小;涂层摩擦学性能测试表明复合涂层的磨损率随初始粉体粒径的增大而减小,初始粉体粒径为100nm左右时,复合涂层的磨损率最低。复合涂层的磨损机制为裂纹扩展导致的磨损剥落。 相似文献
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硬脂酸溶胶凝胶法制备氧化镁纳米微粒的研究 总被引:17,自引:0,他引:17
以硬脂酸为分散剂,采用溶胶凝胶法研究了制备氧化镁纳米微粒的条件,探讨了分散剂用量,反应时间,反应温度,烧结温度和时间对产物粒径与转化率的影响,取得了最佳工艺条件,分别用红外光谱(IR),X射线射末衍射(XRD),透射电镜(TEM)和比表面积(BET)测定,对该纳米微粒的结构与性能进行了表征,结果表明:Mg(NO3)2与CH3(CH2)16COOH的摩尔配比控制在1:1,于90℃反应20min,在470℃热处理3h,得到立方相氧化镁钠米微粒,形貌为椭球体,分散性好,平均粒径约为36nm. 相似文献
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采用高能球磨法制备了W-TiC纳米复合粉体,分别采用无水乙醇、四氯化碳和甲苯作为球磨液体介质,并改变液体介质比,研究其对复合粉体球磨过程的影响,并对球磨后粉体的晶粒尺寸、晶格畸变、颗粒形貌以及比表面积进行测定和分析讨论。结果表明,球磨过程中适量的液体介质可以有效地改善粉体团聚、结块以及黏壁现象,提高出粉率。粉体的比表面积随着液体介质比的增加先增大后减小,无水乙醇的液体介质比为2时,球磨后粉体的比表面最大(2.3m2/g),颗粒形状近似于球形,平均粒径100nm,每个颗粒为多晶结构;液体介质的种类对粉体比表面影响较小;添加液体介质对粉体的晶粒细化有利。 相似文献
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Cemented carbide reinforced nickel-based alloy coating by laser cladding and the wear characteristics 总被引:1,自引:0,他引:1
Composite coatings composed of metal matrix and ceramic particles have received particular attention in surface engineering. In this paper nickel base alloy powder and WC-Co cemented carbide particles have been chosen to manufacture composite coatings by use of kW CO2 laser. Laser processing parameters including output power and scanning speed have been optimized. X-ray diffractor, optical and electron microscopes and energy dispersion spectra have been applied to investigate the phase constituents and microstructures of the coating. Block-on-ring dry sliding wear test and rubber wheel slurry erosive abrasion wear test have been conducted to study the wear properties of the composite coating as well as the reinforcing effect of WC-Co particles. A 50–100 mm wide ring appeared along the particle side of the particle-matrix boundary, showing superior wear and corrosion resistance, higher than even the original central part of the WC-Co particle. The mechanism of its formation has been probed. 相似文献
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超细煤粉的静电分散研究 总被引:1,自引:1,他引:1
为了解决超细煤粉加工和利用过程中的聚团问题,提高煤粉的附加值和功能化利用,本文中采用正交试验的方法研究了静电分散对超细煤粉的分散效果及其主要影响因素,并用高精度粒度分析仪对静电分散前后粒度进行了检测。实验结果表明,静电分散后的粒度明显变小,静电分散作用可保持7d左右。静电分散方法能有效分散空气中超细煤粉的聚团。 相似文献
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利用激光衍射法对注射成形用铁、镍原材料粉末进行粒度测量,分别从超声方式和超声时间上对测量条件进行研究。结果表明,对铁粉,宜在大功率超声装置上将样品分散15min后进行测量;对于镍粉,宜在大功率超声装置上将样品分散30min后进行测量。 相似文献