Preparation and Properties of Al2O3 Ceramic Reinforced Mo-Based Composites by Al(NO3)3 Precursor

2010 ◽  
Vol 150-151 ◽  
pp. 1077-1081
Author(s):  
Liu Jie Xu ◽  
Shi Zhong Wei ◽  
Guo Shang Zhang ◽  
Ji Wen Li ◽  
Xiang Dong Ma ◽  
...  
Keyword(s):  
Raw Materials ◽  
Alumina Content ◽  
Wear Property ◽  
Micro Hardness ◽  
Ceramic Particles ◽  
Al2o3 Ceramic ◽  
Molybdenum Alloys ◽  
Α Al2o3 ◽  
Worn Surface ◽  
Wear Characterization

To enhance the wear resistance of molybdenum alloys, Mo-based composites reinforced by Al2O3 ceramic particles were developed. Using Al(NO3)3 aqueous solution and MoO3 as raw materials, the Molybdenum powders mixed with Al2O3 particles were prepared by liquid-solid incorporation, drying, pyrolysis of Al(NO3)3 and deoxidation of MoO3 by H2. And then the Mo-based composites with 3-10vol.% Alumina were prepared by compaction and sintering at 1840°C. The morphology of the Molybdenum powder and microstructure of the composites were analyzed by SEM and XRD. The micro-hardness, density and wear property of composites were researched. The results showed that α-Al2O3 ceramic particles and Molybdenum matrix compose the composites. With the increase of Alumina content, the molybdenum powders become fine and rule, the grains of composites become fine, the microhardness of Molybdenum matrix increases, and the density first increases and then decreases. The friction coefficient of composite is scarcely affected by the alumina content. While the wear weight of the composite decrease with the increase of Alumina content. There are obvious plow furrow and abrasive dust on the worn surface, showing the abrasive wear characterization.

Microstructure and Properties of Mo-Based Composites Reinforced by Al2O3

2011 ◽  
Vol 120 ◽  
pp. 467-470 ◽  
Author(s):  
Shi Zhong Wei ◽  
Liu Jie Xu ◽  
Guo Shang Zhang ◽  
Ji Wen Li ◽  
Bao Zhu Dai
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Ball Mill ◽  
Raw Materials ◽  
Alumina Content ◽  
Wear Property ◽  
Molybdenum Powder ◽  
Micro Hardness ◽  
Molybdenum Alloys ◽  
Worn Surface

Mo-based composites with Al2O3 particles were developed in order to enhance the wear resistance of molybdenum alloys. Using Al2O3 power and pure Mo power as raw materials, the Molybdenum powders mixed with Al2O3 particles were prepared using planetary ball mill. And then the Mo-based composites with 3-10vol.% Alumina were prepared by compaction and sintering at 1840°C. The morphology of the Molybdenum powder and microstructure of the composites were analyzed by SEM and XRD. The micro-hardness, density and wear property of composites were researched. The results show that the microstructure of composites is composed of α-Al2O3 particles and Molybdenum matrix. With the increase of Alumina content, the microhardness of Molybdenum matrix increases, and the density first increases and then decreases. The friction coefficient of composite is scarcely affected by the alumina content. While the wear resistance of the composites rises with the increase of Alumina content. The wear failure is caused by abrasive wear characterized by obvious plow furrow and abrasive dust on the worn surface.

Structure and Mechanical Properties of Ceramic Coatings Fabricated by Micro-Arc Oxidation

2008 ◽  
Vol 47-50 ◽  
pp. 554-557 ◽  
Author(s):  
Hong Xia Li ◽  
Ren Guo Song ◽  
J. Zhao
Keyword(s):  
High Hardness ◽  
Hardness Test ◽  
Ceramic Coatings ◽  
Elemental Distribution ◽  
Surface Adhesion ◽  
Micro Hardness ◽  
Al2o3 Ceramic ◽  
Micro Arc Oxidation ◽  
Excellent Adhesion ◽  
Α Al2o3

Al2O3 ceramic coatings were directly prepared on 6063 aluminum alloy in borate electrolytes by micro-arc oxidation (MAO) technique. The phase composition, microstructure, elemental distribution, and micro-hardness of Al2O3 ceramic coatings were investigated using X-ray diffraction (XRD), scanning electron microscopy (SEM), and micro-hardness test. XRD results show that the coating consists of α-Al2O3 and γ-Al2O3. SEM results show that the pores with different sizes distributed all over the coating surface. Adhesion and tribological and wear tests were also performed. It was found that ceramic coatings with high hardness, excellent adhesion and wear resistance could be formed.

Preparation of High-Purity Ultrafine α-Al2O3 by Solid-State Reaction at Room Temperature

2008 ◽  
Vol 368-372 ◽  
pp. 683-685
Author(s):  
Cheng Wei Hao ◽  
Bo Lin Wu ◽  
Ji Yan Li
Keyword(s):  
Solid State ◽  
High Purity ◽  
Solid State Reaction ◽  
Room Temperature ◽  
Raw Materials ◽  
Phase Particle ◽  
Phase Transformation Temperature ◽  
Particle Size And Morphology ◽  
Size And Morphology ◽  
Α Al2o3

Ammonium aluminium carbonate hydroxide (AACH), with a small quantity of γ-AlOOH, was synthesized through solid-state reaction at room temperature using AlCl3·6H2O and NH4HCO3 as raw materials and polyethylene glycol (PEG-10000) as the dispersant. After calcined at 1100°C for 1.5h, α-Al2O3 powders with primary particle sizes of 20~30nm were obtained. The crystal phase, particle size and morphology of the high-purity ultrafine α-Al2O3 were characterized. The results showed that a small quantity of γ-AlOOH in the AACH decomposed and formed crystal seeds. The presence of crystal seeds reduced the nucleation activation energy and therefore reduced the phase transformation temperature.

Effects of attapulgite on the worn surface and fretting wear resistance property of UHMWPE composites

2020 ◽  
Vol 72 (7) ◽  
pp. 821-827
Author(s):  
Zhaojie Meng ◽  
Yunxia Wang ◽  
Xiaocui Xin ◽  
Hao Liu ◽  
Yunfeng Yan ◽  
...  
Keyword(s):  
Wear Resistance ◽  
Peer Review ◽  
Filler Content ◽  
Resistance Mechanism ◽  
Three Dimensional ◽  
Fretting Wear ◽  
Wear Property ◽  
Pressing Method ◽  
Content Type ◽  
Worn Surface

Purpose The purpose of this study is to examine the fretting wear property of ultra-high molecular weight polyethylene (UHMWPE)-based composites reinforced by different content of attapulgite. Design/methodology/approach A series of composites were prepared by a hot-pressing method. Fretting tests were carried out using an SRV-IV oscillating reciprocating friction wear tester with a load of 10 N and a frequency of 100 Hz. The morphology of the fracture structure and the worn surface was observed by field-emission scanning electron microscopy, X-ray diffraction and a non-contact three dimensional surface profiler. Findings With the addition of attapulgite, the microstructure of the composites become more regular, and their heat resistance improved. Furthermore, the friction coefficient and the specific wear rate of the composites with lower filler content reduced compared with that of neat UHMWPE, and the optimum filler content is 1 per cent. Originality/value The study investigated the fretting resistance mechanism of the attapulgite in the UHMWPE matrix. The results could help to provide some experimental evidence for the broader application of silicates on the fretting wear resistance of polymers. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-10-2019-0420/

scholarly journals Effect of (Tb+Y)/Al ratio on Microstructure Evolution and Densification Process of (Tb0.6Y0.4)3Al5O12 Transparent Ceramics

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 300 ◽  
Author(s):  
Zhong Wan ◽  
Yinzhen Wang ◽  
Jian Zhang ◽  
Shiwei Wang ◽  
Dan Han ◽  
...  
Keyword(s):  
Microstructure Evolution ◽  
Raw Materials ◽  
Secondary Phase ◽  
Optical Quality ◽  
Transparent Ceramics ◽  
Reactive Sintering ◽  
Densification Process ◽  
Densification Rate ◽  
Grain Growth Kinetics ◽  
Α Al2o3

(Tb0.6Y0.4)3Al5O12 transparent ceramics were successfully fabricated by solid-state reactive sintering using Tb4O7, Y2O3, and α-Al2O3 powders as raw materials. The effect of (Tb+Y)/Al ratio on microstructure evolution and densification process was investigated in detailed. The results showed that the grain growth kinetics were significantly affected by (Tb+Y)/Al ratio. Al-rich and Tb-rich phases appeared in part of the samples of different ratios. Particularly, excess aluminum increased the diffusing process, leading to a higher densification rate, while samples with excess terbium ratios displayed a smaller grain size and lower relative density. The optical quality was highly related to the amount of the secondary phase produced by different (Tb+Y)/Al ratios. Finally, (Tb0.6Y0.4)3Al5O12 transparent ceramics have been fabricated through pre-sintering in vacuum, followed by hot isostatic sintering (HIP), and the best transmittance of sample with a 4 mm thickness was approximately 78% at 1064 nm.

A Study on the Effects of Ceramic Content of CNT / Metal Composite Surface Coatings Fabricated by Cold Spray for Boiling Heat Transfer Enhancement

2012 ◽  
Author(s):  
Edward Joshua Pialago ◽  
Xi Ru Zheng ◽  
Kristian Arvin Ada ◽  
Oh Kyung Kwon ◽  
Dong An Cha ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Cold Spray ◽  
Boiling Heat Transfer ◽  
Heat Transfer Performance ◽  
Raw Materials ◽  
Surface Coatings ◽  
Metal Composite ◽  
Transfer Performance ◽  
Composite Powders ◽  
Ceramic Particles

In this study, the enhancement of boiling heat transfer through surface modification of heat transfer materials by surface coating was investigated. Specifically, the study evaluated how the boiling heat transfer performance of CNT/metal composite coatings, fabricated by the cold gas dynamic spray process, was affected by the addition of different ceramic particles on the raw materials of these surface coatings. These raw materials were composite powders of CNT, Cu powder, and ceramic powders (SiC, AlN, and BN) that were mechanically alloyed using an attrition ball mill. The boiling heat transfer tests were performed in a pool of R134a at a gauge pressure of 2.5 kg/cm2 and liquid temperature of 4.8°C. Test results showed that the addition of ceramic particles in the CNT/Cu composite powders can further augment boiling heat transfer. The augmented boiling heat transfer performance varied with the kind of ceramic powder added and with their quantity. The highest enhancement ratio was 2.57. This was exhibited by a Cu plate specimen that was cold spray coated with (5 vol.% CNT + 95 vol.% Cu) + 20 vol.% AlN composite powder.

Fabrication of a COF-5 membrane on a functionalized α-Al2O3 ceramic support using a microwave irradiation method

2014 ◽  
Vol 50 (12) ◽  
pp. 1462-1464 ◽  
Author(s):  
Dandan Hao ◽  
Jinna Zhang ◽  
Hui Lu ◽  
Wenguang Leng ◽  
Rile Ge ◽  
...  
Keyword(s):  
Microwave Irradiation ◽  
Microwave Irradiation Method ◽  
Al2o3 Ceramic ◽  
Ceramic Support ◽  
Membrane Growth ◽  
Α Al2o3

A novel functionalization strategy was developed by using covalent linkers to promote the COF-5 membrane growth on the α-Al2O3 support.

Research on Molding for Al2O3Ceramic Substrate and its Processing Technic

2010 ◽  
Vol 154-155 ◽  
pp. 1397-1400
Author(s):  
Zhan Xin Zhang ◽  
Hong Kui Hu ◽  
Feng Ming Wang ◽  
Tao Liu
Keyword(s):  
Ph Value ◽  
Glass Mold ◽  
Ceramic Substrate ◽  
Al2o3 Powder ◽  
Al2o3 Ceramic ◽  
Α Al2o3

By adopting technique for forming colloid to manufacture Al2O3 Ceramic Substrate, the effect of aggregation reaction which is caused by pH value, temperature for shaping, evocating agent and some other factors of slurry has been researched in the processes for shaping Substrate. The result addresses that the substrate with well-proportioned in density, contractibility and over 78MPa intensity is able to be made while the pH is about 9, the temperature is between 60 and 70°, the shaping duration is no more than 30 minutes, in glass mold, and with 120 item undersize α-Al2O3 powder. To dunk the desiccating substrate for 20 minutes, it would gain the good flexibility, moreover, it is able to be cut. After it is desiccated again, it becomes firm again, this kind of characteristic can be repeated numbers of times.

Properties of Low-Carbon Al2O3-C Refractories with Different Critical Particle Size

2012 ◽  
Vol 217-219 ◽  
pp. 318-321
Author(s):  
Chong Chong Niu ◽  
Guo Qi Liu ◽  
Xiao Xian Wu ◽  
Jian Bin Yu ◽  
Hong Bin Qin
Keyword(s):  
Particle Size ◽  
Fracture Energy ◽  
Thermal Shock ◽  
Raw Materials ◽  
Modulus Of Rupture ◽  
Thermal Shock Test ◽  
Low Carbon ◽  
Shock Resistance ◽  
Critical Particle Size ◽  
Α Al2o3

Low-carbon Al2O3-C refractories were prepared using white fused corundum, α-Al2O3 powders and flake graphite as main raw materials. The critical particle sizes of corundum selected in this experiment were 0.5mm, 1mm and 2mm. The effects of corundum critical particle size on physical, mechanical and thermo-mechanical properties of low-carbon Al2O3-C refractories were investigated. The results show that the increase of critical particle size is conducive to the improvement of thermal shock resistance and fracture energy, but little effect on thermal expansion. The cold modulus of rupture after thermal shock test of samples using 0.5mm critical particle size corundum was 2.09MPa, while using 2mm critical particle size corundum was 2.98MPa. And the fracture energy increased from 265N/mm to 588N/mm when the critical particle size increased from 0.5mm to 2mm. The effects of critical particle size on apparent porosity, bulk density and modulus of rupture were insignificant.

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