Self—Regulating Behavior of Ferromagnetic Granules in Inductive Sintering Process

1990 ◽  
Vol 195 ◽  
Author(s):  
L.S. Bulatova ◽  
A.V. Dmitriev

ABSTRACTA physical model is presented to describe solid—phase sintering of pressed ferromagnetic powders under conditions of self—organization.

Metals ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 680 ◽  
Author(s):  
Hongfeng Dong ◽  
Peiyou Li ◽  
Taotao Ai ◽  
Wenhu Li

The mechanical properties and microstructure of W-6Ni-4Co alloy through solid phase sintering and two-step sintering process were investigated. The results demonstrated that the particle sizes of W-6Ni-4Co alloy milled powders increased firstly and decreased later during a mechanical alloying process. The shape of alloy milled powders affected that of grains in alloy by solid phase sintering. The shape of W-rich particles in the alloys changed from stripes to network, to polygonal and to subsphaeroidal finally during two-step sintering process. The mechanical properties could be attributed to the densification and microstructure of alloys, and increased during two-step sintering with short dwelling time.


2006 ◽  
Vol 54 (9) ◽  
pp. 69-79 ◽  
Author(s):  
G.R. Xu ◽  
J.L. Zou ◽  
Y. Dai

Dried sludge as additive for making ceramsite is a new effective approach for disposal of sludge. In this study sewage sludge, water glass and clay were chosen as the components, the optimal ratio of the components and the most appropriate conditions were obtained. The functions of primary components in the sintering process, porosity formation mechanism and solid phase reaction also have been discussed. The optimized process parameters were shown as follows: the ratio of dried sludge /clay (wt%) was 33%, ratio of adherent /clay (wt%) was 15%, sintering temperature was 1000 °C, sintering time was 10 min. Bulk density was 582 kg m−3, particle density was 1,033 kg m−3, water absorption was 9.5%, porosity was 43.7%. SEM, EDS, XRD and XRF analyses were also carried out. The results indicate that dried sludge as raw material is a good way for making ceramsite. Biological Aerated Filters (BAFs) with filter media of Guangzhou ceramsite, Jiangxi ceramsite, activated carbon and ceramsite (obtained in test) were selected to treat municipal wastewater. The average removal efficiencies of ceramsite (obtained in test) for turbidity, COD, SCOD and NH3-N were about 96.4%, 76.2%, 59.6% and 82.3% respectively and were higher than those of other ceramsites.


Nanoscale ◽  
2016 ◽  
Vol 8 (8) ◽  
pp. 4579-4587 ◽  
Author(s):  
Chih-Hsien Cheng ◽  
Yu-Chieh Chi ◽  
Chung-Lun Wu ◽  
Chun-Jung Lin ◽  
Ling-Hsuan Tsai ◽  
...  

2013 ◽  
Vol 734-737 ◽  
pp. 2338-2341
Author(s):  
Ru Qin Gao ◽  
Dou Dou Huang ◽  
Zi Kuo Wang

A supporting body of diatomite-based porous ceramics was prepared by a solid-phase sintering process and low-temperature calcination process. nanoTiO2 membrane was loaded on the carrier by the hydrolysis precipitation method and using TiCl4 as the precursor. The influences of various parameters such as the initial concentration of malachite green, the amount of composites, and the initial pH had been investigated. Under the same test conditions, the decolorizing rate of malachite green was higher when the initial concentration was 6 mg/L, the composites dosage was 5 g/L, and the initial pH was 8 respectively. The influence mechanism of the initial concentration of malachite green, the amount of composites, and the initial pH for malachite green was discussed.


2013 ◽  
Vol 745-746 ◽  
pp. 512-516
Author(s):  
Qing Wei Wang ◽  
Hong Zhi Wang ◽  
Wei Ning ◽  
Li Da Luo

The Pr2O3 doped SnO2 dense ceramic was prepared by co-precipitation method and further sintering. Through the micrograph of the cross-sectional microstructure of the electrodes, the sintering process was analyzed and discussed. Results showed that the solid phase sintering was exhibited at the early stage; when sintering was kept going on, the instant liquid phase could be emerged due to the rich dopants in the grain boundary. Finally, there would be much secondary phase existe as the concentration of dopants reached to a certain value.


2005 ◽  
Vol 37 (1) ◽  
pp. 3-17 ◽  
Author(s):  
Arnold Savitskii

Existing theories cannot convincingly explain relationships observed during sintering of mixtures and do not always help solve practical problems of sintering metal materials and ceramics. The main weakness of the known theories is insufficient attention to the phenomenon of alloy formation and its effect on volume changes of compacts, faulty ideas regarding driving forces for the sintering process, the mistaken mechanism of dissolution of solid phase in liquid, and the inaccurate mechanisms of growth and densification during the sintering of mixtures. Besides, obsolete theories are developed, as a rule, on the basis of a two-partial model that does not permit taking into account the skeleton structure of a powder body and the presence of interparticle pores in it. Essentially fresh concepts in the theory of mixture sintering are formulated and defined in this paper. The new approaches eliminate the drawbacks and discrepancies in the existing theories and provide the scientific basis for solid state and liquid phase sintering of mixtures.


2014 ◽  
Vol 552 ◽  
pp. 283-285
Author(s):  
Huan Huan Chen ◽  
Xiao Yan Zhang ◽  
Xi Wei Qi ◽  
Zhao Jie Zhou ◽  
Gui Fang Sun

A series of Fe-doped Bi2(FexGa1-x)4O9 (x=0.1,0.2,0.3,0.4,0.5) ceramics were synthesized by solid-phase method with sintering process. The influences of Fe doping content on phase, morphology, dielectric properties are discussed. XRD results show that there is no second phase in Fe-doped Bi2(FexGa1-x)4O9 ceramics. The SEM analysis indicates the grain size of as-prepared doped samples are relatively uniform and estimated to be about 1–4μm. The permittivity of as-prepared doped samples increases and the dielectric loss decrease compared to pure Bi2Ga4O9 ceramics.


2018 ◽  
Vol 783 ◽  
pp. 144-147
Author(s):  
Jing Wang ◽  
Qin Chen ◽  
Xia Chun Zhu ◽  
Seok Je Lee ◽  
Kyoung Woo Park ◽  
...  

Polycrystalline Ca3-xBixCo4O9 samples have been prepared by solid-phase reaction followed by spark plasma sintering process. The thermoelectric properties have been systematically investigated from room temperature to near 1000K. It is found that the change of the carrier concentration leads to the change of resistivity, which is mainly associated with doping induced point defect phonon scattering. The change of the thermal potential mainly comes from the spin entropy. In addition, polycrystalline Ca3-xBixCo4O9 had a maximum figure of merit of 0.30 at 973 K, which was about 50% higher than Ca3Co4O9. It indicated that doping approach can effectively improve the thermoelectric performance of Ca3Co4O9+δ-based material.


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