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Influence of nano-SiC on microstructure and property of MAO coating formed on AZ91D magnesium alloy 被引量:12
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作者 王淑艳 司乃潮 +1 位作者 夏永平 刘莉 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2015年第6期1926-1934,共9页
Ceramic coating incorporated with nano-SiC was obtained on AZ91D magnesium alloy during MAO by adding nano-SiC into the silicate-aluminate-based composite electrolyte. The microstructure, thickness, phase analysis, el... Ceramic coating incorporated with nano-SiC was obtained on AZ91D magnesium alloy during MAO by adding nano-SiC into the silicate-aluminate-based composite electrolyte. The microstructure, thickness, phase analysis, element composition and hardness of the coatings were respectively investigated by scanning electron microscopy(SEM), film thickness meter, X-ray diffraction (XRD), energy disperse spectroscopy(EDS) and Vickers hardness tester. The wear resistance of Mg alloy and coatings were evaluated by friction and wear apparatus, while the corrosion resistance of Mg alloy and coatings were evaluated by potentiodynamic polarization test and electrochemical impedance spectroscopy (EIS). The results show that after adding nano-SiC into the electrolyte, both the striking voltage and final voltage decrease, the size and number of the micropore on the surface of the coating decrease, the thickness and hardness of the coating increase, both the wear resistance and corrosion resistance of the coating raise. 展开更多
关键词 magnesium alloy micro-arc oxidation nano-sic microstructure PROPERTY
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Nano-SiC薄膜在太阳能电池窗口表面的应用 被引量:3
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作者 王二垒 张秀霞 +2 位作者 张丽霞 陈旭涛 杨小聪 《科学技术与工程》 北大核心 2013年第17期4878-4880,4889,共4页
由于环境的污染使空气中有泥土,太阳能电池在户外使用一段时间后,其窗口表面就会附着一些灰尘颗粒影响其进光量,进而影响太阳能电池的光电转换效率。采用溶胶凝胶法制备并通过热烧结过程,将Nano-SiC透明薄膜制备在太阳能电池窗口表面。... 由于环境的污染使空气中有泥土,太阳能电池在户外使用一段时间后,其窗口表面就会附着一些灰尘颗粒影响其进光量,进而影响太阳能电池的光电转换效率。采用溶胶凝胶法制备并通过热烧结过程,将Nano-SiC透明薄膜制备在太阳能电池窗口表面。通过实验测试了表面制备不同厚度的Nano-SiC薄膜对太阳能电池I-V特性的影响。实验结果表明Nano-SiC薄膜具有很好的光子透过性和自洁能力,能够提高太阳能电池的光电转换效率。 展开更多
关键词 nano-sic薄膜 太阳能电池窗口 光电转换效率 I-V特性
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45#钢表面Ni-P-nano-SiC复合化学镀层的制备 被引量:1
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作者 陈岁元 范红 +1 位作者 梁京 刘常升 《东北大学学报(自然科学版)》 EI CAS CSCD 北大核心 2011年第6期810-813,825,共5页
在优化设计的化学镀基础镀液中通过添加不同含量的纳米SiC颗粒,研究在45#钢表面制备具有纳米SiC颗粒增强的复合镀层及形成机理.利用SEM,XRD和显微硬度计等方法对实验样品的组织结构、形貌、显微硬度及其镀层形成机理进行了研究,结果表明... 在优化设计的化学镀基础镀液中通过添加不同含量的纳米SiC颗粒,研究在45#钢表面制备具有纳米SiC颗粒增强的复合镀层及形成机理.利用SEM,XRD和显微硬度计等方法对实验样品的组织结构、形貌、显微硬度及其镀层形成机理进行了研究,结果表明:实验制备的Ni-P,Ni-P-SiC镀层镀态时硬度分别为572 HV,649 HV,热处理后其表面硬度在400℃时达到最大值1 045 HV和1 341 HV.纳米SiC颗粒在镀液中不参与化学反应,只是与化学反应所产生的Ni和P共同沉积在镀层中起到了复合强化的作用.Ni-P-nano-SiC镀层的生长机理是按层状方式生长,生长方向垂直于钢基体表面.纳米SiC提高了复合化学镀层的生长速度,促进了复合镀层以较薄的分层方式生长. 展开更多
关键词 化学复合镀 Ni-p-nano-sic复合镀层 纳米颗粒复合强化 层状生长
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硅烷偶联剂改性CE/nano-SiC静态力学性能的研究
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作者 张学英 张文根 +2 位作者 祝保林 王君龙 梁国正 《塑料》 CAS CSCD 北大核心 2009年第1期77-79,共3页
采用模塑成型法制备CE/nano-S iC复合材料,分别考察了3种偶联剂表面处理nano-S iC后对其静态力学性能的影响,用透射电子显微镜(TEM)表征了材料的微观结构和形貌特征。结果表明:3种偶联剂的改性效果次序为:KH-560<SCA-3<SEA-171;当... 采用模塑成型法制备CE/nano-S iC复合材料,分别考察了3种偶联剂表面处理nano-S iC后对其静态力学性能的影响,用透射电子显微镜(TEM)表征了材料的微观结构和形貌特征。结果表明:3种偶联剂的改性效果次序为:KH-560<SCA-3<SEA-171;当nano-S iC含量为1.00%时,相对于纯CE的冲击强度和弯曲强度,SEA-171的提高率分别为95.06%和34.69%。 展开更多
关键词 氰酸酯树脂 偶联剂 nano-sic 力学性能 复合材料
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KH-560改性CE/nano-SiC复合材料的韧性和耐热性
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作者 张学英 张文根 +2 位作者 祝保林 王君龙 梁国正 《材料开发与应用》 CAS 2009年第1期1-3,共3页
采用模塑成型法制备CE/nano-SiC复合材料,通过冲击强度测试、TGA分析和DMA分析,发现偶联剂KH-560表面处理nano-SiC后,对其韧性和耐热性具有显著的协同改性作用。相对纯CE,经KH-560表面处理后的CE、1.00%nano-SiC复合材料,冲击强度提高86... 采用模塑成型法制备CE/nano-SiC复合材料,通过冲击强度测试、TGA分析和DMA分析,发现偶联剂KH-560表面处理nano-SiC后,对其韧性和耐热性具有显著的协同改性作用。相对纯CE,经KH-560表面处理后的CE、1.00%nano-SiC复合材料,冲击强度提高86.26%;玻璃化转变温度提高16.71%;失重5%时,热分解温度提高17.25%;450℃时,质量保持率提高59.67%。 展开更多
关键词 氰酸酯树脂 偶联剂 nano-sic 改性研究
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丝网印刷nano-SiC薄膜阴极的电子特性的研究 被引量:3
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作者 张秀霞 雷崇民 +3 位作者 王晓娥 盛洪江 魏舒怡 魏杰 《功能材料》 EI CAS CSCD 北大核心 2010年第4期555-557,561,共4页
研究了低成本大面积丝网印刷在玻璃衬底上均匀的纳米碳化硅(nano-SiC)薄膜的场致发射特性。提出了机械分散团聚的nano-SiC的方法,实验了适合导电玻璃衬底上制备nano-SiC薄膜的浆料配方,摸索导电玻璃衬底上nano-SiC薄膜的烧结工艺,研究... 研究了低成本大面积丝网印刷在玻璃衬底上均匀的纳米碳化硅(nano-SiC)薄膜的场致发射特性。提出了机械分散团聚的nano-SiC的方法,实验了适合导电玻璃衬底上制备nano-SiC薄膜的浆料配方,摸索导电玻璃衬底上nano-SiC薄膜的烧结工艺,研究了不同nano-SiC含量的薄膜的场发射特性,得到了最佳场致发射特性的配方比例。对样品进行微观分析和表征。具有稳定均匀场致发射性能的nano-SiC薄膜可作为显示器器件的阴极材料。 展开更多
关键词 纳米碳化硅薄膜 电子场发射 丝网印刷 后处理过程
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退火处理对Nano-SiC-Al_2O_3/TiC纳米陶瓷复合材料性能的影响 被引量:4
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作者 仝建峰 陈大明 蔡万华 《金属热处理》 CAS CSCD 北大核心 1999年第11期26-27,共2页
研究了退火工艺对纳米陶瓷复合材料力学性能的影响。研究表明,纳米陶瓷复合材料在适当退火工艺下,其抗弯强度和硬度可以提高40% ~50 % ,但断裂韧度略有下降。
关键词 纳米碳化硅 氧化铝 碳化钛 复合材料 退火处理
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CE/nano-SiC复合材料的制备及其改性研究 被引量:2
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作者 张文根 张学英 《中国胶粘剂》 CAS 北大核心 2014年第5期42-45,共4页
采用模塑成型法制备了CE(氰酸酯)/nano-SiC复合材料,通过弯曲强度测定、TGA(热失重分析)法和DMA(动态力学分析)法对复合材料的性能进行了分析。研究结果表明:nano-SiC经硅烷偶联剂(SCA-3)表面处理后,对复合材料的力学性能和耐热性具有... 采用模塑成型法制备了CE(氰酸酯)/nano-SiC复合材料,通过弯曲强度测定、TGA(热失重分析)法和DMA(动态力学分析)法对复合材料的性能进行了分析。研究结果表明:nano-SiC经硅烷偶联剂(SCA-3)表面处理后,对复合材料的力学性能和耐热性具有明显的协同改性作用;当w(nano-SiC)=1%(相对纯CE质量而言)时,nano-SiC经SCA-3表面处理前后,相应复合材料的弯曲强度分别提高了20.84%和32.84%,玻璃化转变温度分别提高了13.09%和18.29%,失重5%时的热分解温度分别提高了12.31%和13.87%,450℃时的质量保持率分别提高了26.24%和42.99%。 展开更多
关键词 氰酸酯 nano—SiC 硅烷偶联剂 复合材料 改性
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Al_2O_3-Coated Nano-SiC Particles Reinforced Al_2O_3 Matrix Composites 被引量:2
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作者 Juxian ZHANG, Jinjun FENG and Longqiao GAOBeijing Vacuum Electronics Research Institute, PO. Box 749 Ext. Box 33, Beijing 100016, China 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2002年第6期541-543,共3页
Properties of Al2O3-coated nano-SiC have been compared with those of as-received SiC. The isoelectric point (IEP) of SiC changed from pH3.4 to pH7.3 after coating with the alumina precursor, which is close to that of ... Properties of Al2O3-coated nano-SiC have been compared with those of as-received SiC. The isoelectric point (IEP) of SiC changed from pH3.4 to pH7.3 after coating with the alumina precursor, which is close to that of alumina. Because both surfaces of coated SiC and AI2O3 possess higher positive charge at pH=4.5-5.0, they are uniformly dispersed in the two-phase aqueous suspensions, Then a mixed powder containing nano-SiC dispersed homogeneously into the Al2O3 matrix was achieved from flocculating the two-phase suspension. Finally, Al2O3/SiC nanocomposites were obtained by coating nano-SiC with Al2O3, in which the majority of SiC particles were located within the AI2O3 grains. The observation by transmission electron microscopy (TEM) and the analysis by the X-ray photoelectron spectroscopy (XPS) showed that cracks propagated towards the intragranular SiC rather than along grain boundaries. 展开更多
关键词 Coated nano-sic Colloidal processing NANOCOMPOSITES Intragranular structure Transgranular fracture
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Nano-SiC薄膜对太阳能电板转换效率影响的研究 被引量:1
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作者 陈旭涛 张秀霞 +4 位作者 王二垒 杨小聪 娄秀丽 温俊霞 江道节 《科学技术与工程》 北大核心 2014年第11期194-195,205,共3页
采用丝网印刷法在太阳能电板超白玻璃表面制备出不同厚度的Nano-SiC薄膜,研究了Nano-SiC薄膜厚度对光子透过率和户外太阳能电板转换效率的影响。结果表明,经过两层Nano-SiC薄膜处理后,超白玻璃的平均光子透过率提高了12%左右;同时Nano-... 采用丝网印刷法在太阳能电板超白玻璃表面制备出不同厚度的Nano-SiC薄膜,研究了Nano-SiC薄膜厚度对光子透过率和户外太阳能电板转换效率的影响。结果表明,经过两层Nano-SiC薄膜处理后,超白玻璃的平均光子透过率提高了12%左右;同时Nano-SiC薄膜可以降低户外太阳能电板转换效率的降低速率,经过两层Nano-SiC薄膜处理后太阳能电板的转换效率降低速率约为未处理时的0.3倍。 展开更多
关键词 丝网印刷 Nano—SiC薄膜 光子透过率 转换效率
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Nano-SiC reinforced Zn biocomposites prepared via laser melting:Microstructure,mechanical properties and biodegradability 被引量:5
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作者 Chengde Gao Meng Yao +2 位作者 Cijun Shuai Shuping Peng Youwen Deng 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2019年第11期2608-2617,共10页
Zn has been regarded as new kind of potential implant biomaterials due to the desirable biodegradability and good biocompatibility,but the low strength and ductility limit its application in bone repairs.In the presen... Zn has been regarded as new kind of potential implant biomaterials due to the desirable biodegradability and good biocompatibility,but the low strength and ductility limit its application in bone repairs.In the present study,nano-SiC was incorporated into Zn matrix via laser melting,aiming to improve the mechanical performance.The microstructure analysis showed that nano-SiC distributed along Zn grain boundaries.During the laser rapid solidification,nano-SiC particles acted as the sites for heterogeneous nucleation,which resulted in the reduction of Zn grain size from 250μm to 15μm with 2 wt%SiC(Zn-2 SiC).Meanwhile,nano-SiC acted as a reinforcer by virtue of Orowan strengthening and dispersion strengthening.As a consequence,the nanocomposites showed maximal compressive yield strength(121.8±5.3 MPa)and high microhardness(72.24±3.01 HV),which were increased by 441%and 78%,respectively,compared with pure Zn.Moreover,fracture analysis indicated a more ductile fracture of the nanocomposites after the incorporation of nano-SiC In addition,the nanocomposites presented favorable biocompatibility and accelerated degradation caused by intergranular corrosion.These findings suggested that the nano-SiC reinforced Zn biocomposites may be the potential candidates for orthopedic implants. 展开更多
关键词 ZN nano-sic BIOCOMPOSITES Laser melting Mechanical properties
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Aging Behavior of Nano-SiC/2014Al Composite Fabricated by Powder Metallurgy and Hot Extrusion Techniques 被引量:5
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作者 Zhiguo Wang Chuanpeng Li +4 位作者 Huiyuan Wang Xian Zhu Min Wu Jiehua Li Qichuan Jiang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2016年第10期1008-1012,共5页
The aging-hardening kinetics of powder metallurgy processed 2014Al alloy and its composite have been studied. The existence of n-SiC particulates leads to the increase of peak hardness. Interestingly, the aginghardeni... The aging-hardening kinetics of powder metallurgy processed 2014Al alloy and its composite have been studied. The existence of n-SiC particulates leads to the increase of peak hardness. Interestingly, the aginghardening peak of the composite takes place at earlier time than that of the unreinforced alloy. Transmission electron microscopy(TEM) studies indicated that the major precipitation phases are Al_5Cu_2Mn_3 and θ′(Al_2Cu). Besides, Ω phase appeared in both specimens at peak hardening condition, which has been rarely observed previously in aluminum metal matrix composites without Ag. Accelerated aging kinetics and increased peak hardness may be attributed to the higher dislocation density resulted from the mismatch of coefficients of thermal expansion between n-SiC and 2014Al matrix. The results are beneficial to fabricating high performance composites for the application in automobile field such as pistons, driveshaft tubes, brake rotors, bicycle frames, railroad brakes. 展开更多
关键词 Metal matrix composites nano-sic Powder metallurgy Hot extrusion Aging hardening
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Friction and wear properties of nano-Si3N4/nano-SiC composite under nanolubricated conditions 被引量:1
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作者 M.S.CHAROO M.F.WANI 《Journal of Advanced Ceramics》 CSCD 2016年第2期145-152,共8页
关键词 NANO-CERAMICS nanolubrication nano-si3N4/nano-sic FRICTION WEAR
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Effect of Nano-SiC and Nano-Si Doping on Critical Current Density of MgB_2
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作者 H.K.Liu S.H.Zhou +6 位作者 S.Soltanian J.Horvat A.V.Pan M.J.Qin X.L.Wang M.Lonescu S.X.Dou 《Tsinghua Science and Technology》 SCIE EI CAS 2003年第3期307-315,共9页
The discovery of superconductivity in magnesium diboride (MgB2) has opened up a new field in materials science research. It offers a possibility of a new class of high performance superconducting materials for practic... The discovery of superconductivity in magnesium diboride (MgB2) has opened up a new field in materials science research. It offers a possibility of a new class of high performance superconducting materials for practical applications because of the relatively low cost of fabrication, high critical current densities (Jc) and fields, large coherence length, absence of weak links, higher Tc(TC = 39K) compared with Nb3Sn and Nb-Ti alloys (two or four times that of Nb,,Sn and Nb-Ti alloys). However, the weak flux pinning in the magnetic field remains a major challenge. This paper reports the most interesting results on nanomaterial (SiC and Si) doping in magnesium diboride. The high density of nano-scale defects introduced by doping is responsible for the enhanced pinning. The fabrication method, critical current density, microstructures, flux pinning and cost for magnesium diboride bulks, wires and tapes are also discussed. It is believed that high performance SiC doped MgB2 will have a great potential for many practical applications at 5K to 25K up to 5T. 展开更多
关键词 magnesium diboride (MgB2) MgB2/Fe wires doped with nano-sic MgB2/Fe wires doped with nano-si critical current density flux pinning
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Effect of Gr Content and Hot Extrusion on Tensile Properties of(Nano-SiCp+Gr)/Cu Composites Fabricated by Powder Metallurgy
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作者 王桂松 罗阳 +3 位作者 刘宝玺 尹成 耿林 黄玉东 《Journal of Shanghai Jiaotong university(Science)》 EI 2012年第6期658-662,共5页
Novel hybrid Cu matrix composites reinforced by graphite(Gr) particle with volume fraction of 5%- 15%and nano-SiC particle(nano-SiCp) with volume fraction of 3%have been prepared by powder metallurgy.The results show ... Novel hybrid Cu matrix composites reinforced by graphite(Gr) particle with volume fraction of 5%- 15%and nano-SiC particle(nano-SiCp) with volume fraction of 3%have been prepared by powder metallurgy.The results show that Gr and nano-SiCp distribute uniformly in the Cu matrix.With increasing the volume fraction of Gr,the tensile strength of the composites decreases from 114 to 51 MPa and the elastic modulus decreases from 75 to 60 GPa.Compared with the sintered composites,the tensile properties including elastic modulus,tensile strength,yield strength and tensile elongation of the hot-extruded(nano-SiCp+Gr)/Cu composites are improved greatly due to higher relative density of the composites and more uniform distribution of Gr and nano-SiCp,in addition to finer grain size of the matrix as a result of dynamic recovery and recrystallization which occur during hot extrusion process. 展开更多
关键词 Cu composites microstructure properties graphite nano-sic particle nano-sicp)
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纳米SiC颗粒对镁合金搅拌摩擦焊接头性能影响研究
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作者 高辉 张楷 +1 位作者 林渊浩 雷丹 《制造技术与机床》 北大核心 2024年第3期108-114,共7页
为提高AZ31镁合金焊接接头的综合性能,文章分别研究了无纳米SiC-1道次、添加纳米SiC-1道次和SiC-4道次的搅拌摩擦焊焊接接头,通过光学显微镜、显微硬度仪和拉伸试验机分析了焊接接头的微观组织与力学性能;利用电化学工作站研究了接头的... 为提高AZ31镁合金焊接接头的综合性能,文章分别研究了无纳米SiC-1道次、添加纳米SiC-1道次和SiC-4道次的搅拌摩擦焊焊接接头,通过光学显微镜、显微硬度仪和拉伸试验机分析了焊接接头的微观组织与力学性能;利用电化学工作站研究了接头的腐蚀行为,采用扫描电镜、EDS和XRD分析了接头的腐蚀形貌、元素成分和物相组成。结果表明,搅拌摩擦焊焊接接头成形良好、无缺陷;接头焊核区组织为均匀的等轴状晶粒,焊接道次的增加可有效改善SiC颗粒的分布情况,异质形核位点的存在起到了晶粒细化的作用,提高了接头的力学性能;在3.5%NaCl溶液腐蚀试验中,含SiC颗粒的接头耐腐蚀性能提升,其中SiC-4道次的接头耐腐蚀性能最佳。 展开更多
关键词 纳米SIC 搅拌摩擦焊 微观组织 力学性能 电化学腐蚀
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碳化硅纳米介质电火花线切割加工研究
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作者 陈成 滕凯 孙涛 《机械设计与制造》 北大核心 2024年第4期244-247,共4页
采用SiC纳米混粉工作液对Cr12MoV模具钢进行高速走丝线切割加工试验,重点分析了脉冲宽度、脉冲间隔、峰值电流和混粉浓度对切割加工的影响。试验表明,在脉冲宽度45μs,脉冲间隔6倍,峰值电流25A,混粉浓度0.3g/L的加工条件下,采用混粉工... 采用SiC纳米混粉工作液对Cr12MoV模具钢进行高速走丝线切割加工试验,重点分析了脉冲宽度、脉冲间隔、峰值电流和混粉浓度对切割加工的影响。试验表明,在脉冲宽度45μs,脉冲间隔6倍,峰值电流25A,混粉浓度0.3g/L的加工条件下,采用混粉工作液较采用常规工作液加工的切割速度提高21.16%,表面粗糙度降低15.05%。研究认为,纳米微粒的介入,极间绝缘性降低,放电间隙增大,改善了极间放电条件,提高了工件加工稳定性和切割速度;同时,纳米微粒促使极间火花放电通道增多、放电点分散,提高了工件表面加工质量。 展开更多
关键词 电火花线切割 混粉 正交试验 SiC纳米介质
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激光功率对PLC控制的SLM成形SiC增强铝基复合材料组织与性能的影响
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作者 张大俊 宋黎明 +1 位作者 李恒 邢峰 《精密成形工程》 北大核心 2024年第6期92-99,共8页
目的提升激光选区熔化成形(SLM)SiC增强铝基复合材料的力学性能。方法以球形纳米SiC和类球形AlSi10Mg粉末为原料,采用球磨工艺和基于PLC控制的SLM技术制备了SiC增强铝基复合材料(SiC/AlSi10Mg),考察了激光功率对复合材料物相、显微组织... 目的提升激光选区熔化成形(SLM)SiC增强铝基复合材料的力学性能。方法以球形纳米SiC和类球形AlSi10Mg粉末为原料,采用球磨工艺和基于PLC控制的SLM技术制备了SiC增强铝基复合材料(SiC/AlSi10Mg),考察了激光功率对复合材料物相、显微组织和力学性能的影响。结果复合粉末和激光功率为120~240 W的复合材料都主要含Al相和Si相;随着激光功率的增大,Al相择优结晶取向由(111)晶面转变到(200)晶面,在较高激光功率下,SLM成形试样中SiC熔化并与基体材料发生反应形成了Al4SiC4、Al4C3碳化物。在不同激光功率的SLM成形复合材料中都可见暗黑色α-Al基体和灰白色Al-Si共晶;随着激光功率增至210 W,Al-Si共晶组织逐渐碎片化并演变为网状,平均晶粒尺寸和小角度晶界体积分数逐渐增大。当激光功率从150 W增至240 W时,复合材料的纳米硬度和弹性模量先增后减,压缩强度逐渐减小,抗拉强度逐渐增大、断后伸长率先减后增而后又减小。结论当激光功率为210 W时,SiC增强铝基复合材料具有良好的综合力学性能,这主要与组织均匀化、晶粒细化以及碳化物/基体界面结合改善等有关。 展开更多
关键词 球形纳米SiC AlSi10Mg 激光选区熔化成形 显微组织 力学性能
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In situ modification of heavy oil catalyzed by nanosized metal-organic framework at mild temperature and its mechanism
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作者 Li Wang Ji-Xiang Guo +3 位作者 Rui-Ying Xiong Chen-Hao Gao Xiao-Jun Zhang Dan Luo 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2024年第3期166-173,共8页
Two catalysts, nano-sized cobalt-metal-organic framework(Co-MOF) and nickel(Ni)-MOF, were successfully prepared by the modification method. Tetralin(C10H12) was used as the hydrogen donor for the catalytic cracking an... Two catalysts, nano-sized cobalt-metal-organic framework(Co-MOF) and nickel(Ni)-MOF, were successfully prepared by the modification method. Tetralin(C10H12) was used as the hydrogen donor for the catalytic cracking and hydrogenation modification study of the dehydrated crude oil from the Shengli Oilfield. The optimal reaction conditions were determined through orthogonal experiments, and the components of the crude oil and modified oil samples were analyzed. The results revealed that the nanoMOF catalysts were successfully prepared and exhibited high catalytic activity. They could catalyze the cracking of large molecules in heavy oil at mild temperatures(<300°C), leading to the decomposition of the hydrogen donor. When the mass fraction of the catalyst was 0.2%, the mass fraction of the hydrogen donor was 1%, and the reaction temperature was 280°C, the Ni-MOF showed the best catalytic viscosity reduction effect. It could reduce the viscosity of heavy oil at 50°C from 15761.9 m Pa.s to 1266.2 m Pa.s,with a viscosity reduction rate of 91.97%. The modification effect of Co-MOF was the next best, which could reduce the viscosity of heavy oil to 2500.1 m Pa.s with a viscosity reduction rate of 84.14%. Molecular dynamics simulations revealed a strong interaction force between the MOF surface and asphaltene molecules. In the process of heavy-oil catalytic hydrogenation, the nano-MOF catalyst exhibited high catalytic activity. On the one hand, the empty d orbitals outside the metal atoms in the catalyst could polarize the carbon atoms in the organic matter, accelerating the breaking of long chains. On the other hand, the metal atoms in the catalyst could bond with the carbon σ bonds, breaking the carbon-carbon bonds. This disrupted the structure of the recombined components in the crude oil, irreversibly reducing the viscosity of the heavy oil and improving its fluidity. 展开更多
关键词 nano-sized MOF Petroleum Viscosity reduction Catalyst NANOMATERIALS
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Improving creep strength of the fine-grained heat-affected zone of novel 9Cr martensitic heat-resistant steel via modified thermo-mechanical treatment
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作者 Jingwen Zhang Liming Yu +6 位作者 Yongchang Liu Ran Ding Chenxi Liu Zongqing Ma Huijun Li Qiuzhi Gao Hui Wang 《International Journal of Minerals,Metallurgy and Materials》 SCIE EI CAS CSCD 2024年第5期1037-1047,共11页
The infamous type Ⅳ failure within the fine-grained heat-affected zone (FGHAZ) in G115 steel weldments seriously threatens the safe operation of ultra-supercritical (USC) power plants.In this work,the traditional the... The infamous type Ⅳ failure within the fine-grained heat-affected zone (FGHAZ) in G115 steel weldments seriously threatens the safe operation of ultra-supercritical (USC) power plants.In this work,the traditional thermo-mechanical treatment was modified via the replacement of hot-rolling with cold rolling,i.e.,normalizing,cold rolling,and tempering (NCT),which was developed to improve the creep strength of the FGHAZ in G115 steel weldments.The NCT treatment effectively promoted the dissolution of preformed M_(23)C_(6)particles and relieved the boundary segregation of C and Cr during welding thermal cycling,which accelerated the dispersed reprecipitation of M_(23)C_(6) particles within the fresh reaustenitized grains during post-weld heat treatment.In addition,the precipitation of Cu-rich phases and MX particles was promoted evidently due to the deformation-induced dislocations.As a result,the interacting actions between precipitates,dislocations,and boundaries during creep were reinforced considerably.Following this strategy,the creep rupture life of the FGHAZ in G115 steel weldments can be prolonged by 18.6%,which can further push the application of G115 steel in USC power plants. 展开更多
关键词 G115 steel fine-grained heat-affected zone creep strength element segregation nano-sized precipitates
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