scholarly journals Corrosion behaviour of the NiTiX (X = Si, Mg, Al) alloy prepared by self-propagating high-temperature synthesis

2021 ◽  
Vol 65 (2) ◽  
pp. 57-64
Author(s):  
D. Alferi ◽  
V. Hybášek ◽  
P. Novák ◽  
J. Fojt

Abstract The NiTi alloys are used in the biomaterial field, because of their shape memory, superelasticity, and good corrosion resistance. The influence of alloying elements on the corrosion behaviour of NiTi was studied in this research. Samples were made by the self-propagating high-temperature synthesis method, milled, and then sintered by the spark plasma sintering method. Si, Mg, and Al were used as alloying elements always in 5 wt.%. Studied materials were compared with reference cast NiTi. Polarization resistance was measured after 1 and 12 hours of stabilization in phosphate-buffered saline. It was found out that alloying elements do not have a clear effect on polarization resistance. Si increased Rp and on the other hand, Al decreased it. Measurement of cyclic potentiodynamic polarization in PBS was conducted, too. All studied samples showed signs of localized corrosion. Corrosion was probably initiated in pores, which are presented on the surface due to used manufacturing technology.

2003 ◽  
Vol 18 (8) ◽  
pp. 1842-1848 ◽  
Author(s):  
F. Maglia ◽  
C. Milanese ◽  
U. Anselmi-Tamburini ◽  
Z. A. Munir

Microalloying of MoSi2 to form Mo(1−x)MexSi2 (Me = Nb or V) was investigated by the self-propagating high-temperature synthesis method. With alloying element contents up to 5 at.%, a homogeneous C11b solid solution was obtained. For higher contents of alloying elements, the product contained both the C11b and the hexagonal C40 phases. The relative amount of the C40 phase increases with an increase in the content of alloying metals in the starting mixture. The alloying element content in the hexagonal C40 Mo(1−x)MexSi2 phase was nearly constant at a level of about 12 at.% for all starting compositions. In contrast, the content of the alloying elements in the tetragonal phase is considerably lower (around 4 at.%) and increases slightly as the Me content in the starting mixture is increased.


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhennan Huang ◽  
Yonggang Yao ◽  
Zhenqian Pang ◽  
Yifei Yuan ◽  
Tangyuan Li ◽  
...  

AbstractDirect formation of ultra-small nanoparticles on carbon supports by rapid high temperature synthesis method offers new opportunities for scalable nanomanufacturing and the synthesis of stable multi-elemental nanoparticles. However, the underlying mechanisms affecting the dispersion and stability of nanoparticles on the supports during high temperature processing remain enigmatic. In this work, we report the observation of metallic nanoparticles formation and stabilization on carbon supports through in situ Joule heating method. We find that the formation of metallic nanoparticles is associated with the simultaneous phase transition of amorphous carbon to a highly defective turbostratic graphite (T-graphite). Molecular dynamic (MD) simulations suggest that the defective T-graphite provide numerous nucleation sites for the nanoparticles to form. Furthermore, the nanoparticles partially intercalate and take root on edge planes, leading to high binding energy on support. This interaction between nanoparticles and T-graphite substrate strengthens the anchoring and provides excellent thermal stability to the nanoparticles. These findings provide mechanistic understanding of rapid high temperature synthesis of metal nanoparticles on carbon supports and the origin of their stability.


2018 ◽  
Vol 243 ◽  
pp. 00010 ◽  
Author(s):  
Ilya Zhukov ◽  
Vladimir Promakhov ◽  
Yana Dubkova ◽  
Alexey Matveev ◽  
Mansur Ziatdinov ◽  
...  

The paper presents microstructure, composition, and burning rate of Al alloy produced by high-temperature synthesis (SHS) from powder mixture Al-Ti-B4C with different concentration of Al powder. It has been established that the phase composition of materials obtained at gas-free combustion includes TiB2, Al, and TiC. It is shown that Al content growth powder in initial Al-Ti- B4C mixture from 7.5 to 40 wt.% reduces the burning rate of the powder from 9*10-3 to 1.8*10-3 m/s. For the system consisting of 60 wt.% of (Ti + B4C) and 40 wt.% of Al there is the increase in the porosity of the compacted initial powder mixture from 30 to 51 and reduction in the burning rate from 1.8 * 10-3 to 1 * 10-3 m/s. The introduction of 0.2 wt.% of the obtained SHS materials into the melt of pure aluminum causes reduction of the grain size of the resulting alloy from 1200 to 410 μm.


2014 ◽  
Vol 900 ◽  
pp. 141-145 ◽  
Author(s):  
Can Feng Fang ◽  
Guang Xu Liu ◽  
Ling Gang Meng ◽  
Xing Guo Zhang

The effects of in-situ TiB2 particle fabricated from Al-Ti-B system via the self-propagating high-temperature synthesis (SHS) reaction technology on microstructure and mechanical properties of Mg-Sn-Zn-Al alloy were investigated. The results indicate that the size of the Mg2Sn and α-Mg+Mg32(Al,Zn)49 phase becomes coarser with the increasing content of Al-Ti-B preform, meanwhile the amount of eutectic α-Mg+Mg32(Al,Zn)49 phase increases too. The addition of Al-Ti-B is favorable toward promoting the strength of composites, but deteriorates elongation. The resulting as-extruded composite material with 4 wt.% Al-Ti-B preform exhibits good overall mechanical properties with an ultimate tensile strength of 291 MPa and an elongation over 2 %.


2009 ◽  
Vol 467 (1-2) ◽  
pp. 514-523 ◽  
Author(s):  
Chyi-Ching Hwang ◽  
Cheng-Shiung Lin ◽  
Gaw-Pying Wang ◽  
Cheng-Hsiung Peng ◽  
Shyan-Lung Chung

1993 ◽  
Vol 12 (7) ◽  
pp. 500-501 ◽  
Author(s):  
M. Ohyanagi ◽  
M. Koizumi ◽  
K. Tanihata ◽  
Y. Miyamoto ◽  
0. Yamada ◽  
...  

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