Study of the microstructure and mechanical properties of halloysite–kaolinite/BaCO3ceramic composites

Clay Minerals ◽  
2018 ◽  
Vol 53 (3) ◽  
pp. 403-412
Author(s):  
Nedjima Bouzidi ◽  
Athmane Bouzidi ◽  
Raphael Oliveira Nunes ◽  
Djoudi Merabet

ABSTRACTThe present study examined the microstructure and mechanical properties of ceramic composites based on a kaolin from Djebel Debbagh, northeast Algeria, composed mainly of kaolinite and halloysite with the addition of various amounts of BaCO3. The composites were prepared by high-energy ball milling and sintered at 1100°C and 1200°C for 3 h. The samples sintered at 1200°C without BaCO3were composed mainly of mullite, which disappeared with increasing BaCO3content. X-ray diffraction investigation showed the presence of hexacelsian (BaAl2SiO6and BaAl2Si2O8), which disappeared at BaCO3contents >50 wt.% in favour of barium aluminium and barium silicate phases. At 40 wt.% BaCO3content, the porosity of the composites decreased from 0.7% to 0.1% and the microhardness increased from 7 to 8 GPa, respectively, at 1100°C and 1200°C due to the amorphous phase.

2006 ◽  
Vol 168 (1-3) ◽  
pp. 1057-1063 ◽  
Author(s):  
Ligia E. Zamora ◽  
G. A. Perez Alcazar ◽  
J. M. Greneche ◽  
S. Suriñach

2006 ◽  
Vol 510-511 ◽  
pp. 698-701
Author(s):  
Pyuck Pa Choi ◽  
Young Soon Kwon ◽  
Ji Soon Kim ◽  
Dae Hwan Kwon

Mechanically induced crystallization of an amorphous Fe90Zr10 alloy was studied by means of X-ray diffraction (XRD) and differential scanning calorimetry (DSC). Under high-energy ball-milling in an AGO-2 mill, melt-spun Fe90Zr10 ribbons undergo crystallization into BCC α- Fe(Zr). Zr atoms are found to be solved in the Fe(Zr) grains up to a maximum supersaturation of about 3.5 at.% Zr, where it can be presumed that the remaining Zr atoms are segregated in the grainboundaries. The decomposition degree of the amorphous phase increases with increasing milling time and intensity. It is proposed that the observed crystallization is deformation-induced and rather not attribute to local temperature rises during ball-collisions.


2007 ◽  
Vol 353-358 ◽  
pp. 1505-1508
Author(s):  
Zhi Hua Yang ◽  
Yu Zhou ◽  
De Chang Jia ◽  
Qing Chang Meng ◽  
Chang Qing Yu

Amorphous Si-B-C-N ceramics obtained by high energy ball milling and hot pressing using hexagonal boron nitride (h-BN), graphite (C) and amorphous Si as starting materials have been studied. The mechanical milling with high energy resulted in the generation of large amounts of amorphous composites only milled for 5 h. Si-B-C-N powders were consolidation by hot pressing at 1850 °C. X-ray diffraction (XRD) and transmission electron microscopy (TEM) show that small amount of BN and SiC crystal lies in the amorphous matrix. The flexural strength reached the maximal value of 137.2 MPa at a mole ratio of BN/(Si+C) being 0.6.


2011 ◽  
Vol 319-320 ◽  
pp. 61-63 ◽  
Author(s):  
Xiu Yan Guo ◽  
Guo Jin Ma ◽  
Shi Kun Xie ◽  
Rong Xi Yi ◽  
Zhi Gao

Cu-4% mixed-powder consisting of rough copper powder and graphite powder was separately mechanical alloyed by high-energy ball milling. The phases and micrograph of these powders were determined by X-ray diffraction and scanning electron microscopy (SEM). The results show an increase in the lattice parameter of copper with milling times, up to a saturation value of about 24h; There was an absence of graphite reflections from X-ray diffractograms after longer milling times.


2016 ◽  
Vol 869 ◽  
pp. 19-24
Author(s):  
Lucas Moreira Ferreira ◽  
D.S. Mégda ◽  
A.C. de Souza ◽  
Rodrigo Fernando Costa Marques ◽  
Erika Coaglia Trindade Ramos ◽  
...  

This work evaluated on the structural modification during high-energy ball milling of the Si-50C, Si-42.9C-19.1B e Si-33.3C-44.4B (at.-%) powder mixtures from elemental powders. Electron images revealed on occurrence of continuous fracture mechanisms in brittle particles during their processing, which presented rounded particles lower than 10 μm. X-ray diffraction results of Si-50C powders indicated that the intensity of Si peaks was slightly reduced after milling for 17 h, which were moved to the direction of larger diffraction angles after 7 h of milling, suggesting that carbon atoms were dissolved into the Si lattice in order to form an extended solid solution. Following, these values were increased due to the discrete exothermic formation of the SiC compound. In Si-C-B powder mixtures, the SiC and B4C compounds were formed after milling for 7 h.


CORROSION ◽  
10.5006/3633 ◽  
2020 ◽  
Author(s):  
Mohammad Umar Farooq Khan ◽  
Taban Larimian ◽  
Tushar Borkar ◽  
Rajeev Gupta

ABSTRACT In this work, nine nanocrystalline binary Mg alloys synthesized by high energy ball milling. The compositions, Mg-5wt.%M (M- Cr, Ge, Mn, Mo, Ta, Ti, V, Y, Zn) were milled with an objective of achieving non-equilibrium alloying. The milled alloys were consolidated via cold compaction (CC) at 25 ï‚°C and spark plasma sintering (SPS) at 300 ï‚°C. X-ray diffraction (XRD) analysis indicated grain refinement below 100 nm, and the scanning electron microscopy revealed homogeneous microstructures for all compositions. X-ray diffraction analysis revealed that most of the alloys showed a change in the lattice parameter, which indicates the formation of a solid solution. A significant increase in the hardness compared to unmilled Mg was observed for all the alloys. The corrosion behavior was improved in all the binary alloys compared to milled Mg. A significant decrease in the cathodic kinetics was evident due to Ge and Zn additions. The influence of the alloying elements on corrosion behavior has been categorized and discussed based on the electrochemical response of their respective binary Mg alloy.


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