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2023 Vol. 28, No. 6
Published: 2023-12-15
Engineering and Technology
Theoretical Research
Theoretical Research
509
Performance and mechanism of ZrMnFe based inspiratory alloy adsorbing CO
2
YANG Qiaobin, ZENG Fanhao, HUANG Rui, GAO Yafang
DOI: 10.19976/j.cnki.43-1448/TF.2023023
In this paper, Ti
x
Zr
1-
x
MnFe (
x
=0, 0.25, mole fraction) inspiratory alloy with a single C14 Laves phase structure was prepared by arc melting method. CO
2
gas adsorption reaction for ZrMnFe was tested by a self-made simple Sieverts constant volume equipment between 660-700 ℃, to study the adsorption performance as well as the adsorption behavior to CO
2
gas. The results show that with the increase of temperature, the adsorption capacity of CO
2
increases first and then decreases, and the maximum adsorption capacity is 3.869 mmol/g at 680 ℃, showing the best adsorption performance. After obtaining Ti
x
Zr
1-
x
MnFe alloy by Ti doping, the adsorption capacity increases by 19.2% compared with that before doping, but the adsorption rate decreases from 0.301 mmol/(g·h) to 0.119 mmol/(g·h) in the first 8 h. The adsorption mechanism was studied based on the first principles, by comparing the adsorption energies, we obtained the optimal adsorption position which is the horizontal orientation vacancy on the surface of ZrMnFe (110), and the adsorption energy is 5.531 eV. Under the study to density of state, it was found that the interaction between the surface of ZrMnFe (110) and CO
2
gas molecules is mainly because of the hybridization of 2s orbitals of O and 4p and 4d orbitals of Zr atom.
2023 Vol. 28 (6): 509-521 [
Abstract
] (
990
)
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(0 KB)
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539
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Engineering and Technology
522
Optical, electrical, and magnetic properties of Nd
3+
, Sm
3+
, and Eu
3+
single-doped NiTiO
3
YU Pengfei, TURSUN Rabigul
DOI: 10.19976/j.cnki.43-1448/TF.2023066
Nanosized Ni
1-
x
R
x
TiO
3
(R=Nd, Sm and Eu;
x
=0, 0.05 and 0.1) powders were synthesized by sol-gel method. The effects of Nd, Sm, and Eu doping on the microstructure and optical, electrical, and magnetic properties of NiTiO
3
were systematically studied using characterization techniques such as X-ray diffraction, scanning electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy, and physical property measurement system. The results show that all samples exhibit charge transfer of O—Ti bonds and O—Ni bonds (200-365 nm), spin-allowed transition of Ni
2+
from
3
A
2g
(
3
F) to
3
T
1g
(
3
P) (450 nm), spin-forbidden transitions of
1
T
2g
(
1
D) and
1
A
1g
(
1
G) (490-520 nm), and spin-forbidden transition of
1
E
g
(
1
D) (743 nm). Absorption spectra of Nd- doped samples exhibit an absorption peak near 588 nm correlated with the electronic transition of Nb
3+
at the octahedral position, which change the samples color from yellow to green. All samples exhibit antiferromagnetism and ferroelectricity at room temperature, and Nd, Sm, and Eu doping at the Ni site significantly enhance the ferroelectricity of NiTiO
3
. Doping elements with larger ionic radii cause lattice distortion, promote the rotation of ferroelectric domains, and enhancc the ferroelectricity.
2023 Vol. 28 (6): 522-533 [
Abstract
] (
183
)
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506
)
534
Effects of resin-coated graphite content on the microstructure and properties of copper matrix composites
SUN Zhen, XU Yongxiang, ZHU Jiamin, ZHANG Qianqian, FANG Zhou, CHEN Xubin, FANG Huachan, ZHU Mengzhen
DOI: 10.19976/j.cnki.43-1448/TF.2023029
Resin-coated graphite/copper composites were prepared by powder metallurgy pressure sintering process using resin-coated graphite and electrolytic copper powders as raw materials, the density, porosity, conductivity, hardness, bending strength, shear strength, and friction property of the composites were measured, the effects of resin-coated graphite content on the microstructure and properties of copper matrix composites were studied by scanning electron microscope. The results show that the continuity of copper matrix gradually decreases, and the distribution of graphite is gradually changed from discrete to aggregate with the increase of resin-coated graphite content. The high content of graphite hinders the sintering densification of copper particles, and as a “defect”, graphite inhibits the sintering continuity of copper matrix, meanwhile the density, conductivity, hardness, bending strength, and shear strength of the composites are decreased. As a lubricating phase, the graphite can effectively improve the friction and wear property. When the addition of resin-coated graphite reaches 16% (mass fraction), the friction coefficient of the composites is the lowest (0.23), the friction coefficient curve is relatively stable, the friction surface is the smoothest, and the friction and wear property is the best.
2023 Vol. 28 (6): 534-544 [
Abstract
] (
222
)
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361
)
545
Low pressure rapid hydrogenation induced oxygen vacancy to enhance the photocatalytic degradation performance of TiO
2
CHEN Fenglei, YANG Wanlin, ZHU Junkui, WEI Qiuping, ZHANG Long, LI Jing, MA Li
DOI: 10.19976/j.cnki.43-1448/TF.2023037
A tube furnace was used to perform low-pressure rapid hydrogenation treatment on TiO
2
photocatalyst (P25) at 300, 400, and 500 ℃, and the effects of hydrogenation temperature on the phase structure, photoelectrochemical performance, and catalytic degradation activity of the sample were studied. The results show that the oxygen vacancy concentration, photogenerated carrier separation efficiency, visible light absorption performance, carrier concentration, and photocatalytic activity of P25 appear to first increase and then decrease as the hydrogenation temperature increases. P25 hydrogenated at 400 ℃ for 1 h has the best performance above. BET (Brunauer-Emmett-Teller) specific surface area of P25 is not sensitive to the change of hydrogenation temperature, indicating that low-pressure rapid hydrogenation can introduce oxygen vacancies while avoiding loss of specific surface area, inhibit the recombination of electron-hole pairs, improve light absorption performance and carrier concentration, thereby improving P25 photocatalytic performance. After hydrogenation treatment at 400 ℃ for 1 h, the reaction rate constant of P25 is 1.63 times than that of untreated P25.
2023 Vol. 28 (6): 545-553 [
Abstract
] (
219
)
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(739 KB) (
539
)
554
Study on performance of SiC whisker reinforced high entropy alloy bonded Ti(C,N) cermet
ZHOU Xingyu, LIU Meiling, CAO Yajing, ZHANG Qiwei, CHEN Chenzi
DOI: 10.19976/j.cnki.43-1448/TF.2023074
In order to improve the bending strength of high entropy alloy bonded cermet, SiC whiskers were added in Al
0.1
CoCrFeNiV
0.1
bonded Ti(C,N) cermet, and the effects of SiC whiskers on the phase, microstructure, mechanical performance, and friction and wear performance of cermet were studied. The results show that few addition of SiC whiskers can promote the solid solution of carbide and refine the Ti(C,N) grains, but the excessive addition brings clusters of solid solution. When
w
(SiC)=1%, the bending strength and fracture toughness of cermet are evidently improved, the increasing rate of bending strength is 21.4%; during the process of friction, the cermet forms continuous and smooth tribolayer on the surface, exhibiting low and stable friction coefficient with wear ratio nearly to 10
-6
level.
2023 Vol. 28 (6): 554-564 [
Abstract
] (
253
)
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549
)
565
Biphasic flow ablation properties and ablation resistance mechanisms of C/SiC-ZrB
2
-TiB
2
composites
ZHANG Jiancheng, ZENG Yi, HU Jinrun, LI Tianyou, WANG Jiajun
DOI: 10.19976/j.cnki.43-1448/TF.2023055
The C/SiC-ZrB
2
-TiB
2
composites were prepared by reactive melt infiltration process. The ablation properties of the composites were tested under a single plasma heat flow and a biphasic flow ablation environment in which the heat flow was coupled with the particle flow, respectively, and the ablation resistance mechanism of the composites was investigated. The results show that the C/SiC-ZrB
2
-TiB
2
composites exhibit excellent ablation resistance in both thermal environments. The linear ablative rates of the composites are 0.38 μm/s and 19.80 μm/s under the action of single heat flow at ablation temperatures of 1 920 ℃ and 2 230 ℃, respectively, and a stable oxide layer consisting of Zr
x
Ti
1-
x
O
2
skeleton and liquid filled phase is formed on the surface, which can slow down the ablation. The linear ablative rates of the composites under biphasic flow are 2.93 μm/s and 21.91 μm/s at ablation temperatures of 2 020 ℃ and 2 190 ℃, respectively. SiC-ZrB
2
-TiB
2
ceramic matrix and its oxide layer can maintain sufficient strength at higher temperatures to resist particle exfoliation, and the carbon fibre ablation level is low, which can provide a better reinforcement and toughening effect.
2023 Vol. 28 (6): 565-579 [
Abstract
] (
245
)
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432
)
580
Rheological properties of SiC slurry and direct-ink writing of porous ceramic
WANG Xiaofeng, LIU Zirui, ZHOU Hongli, PENG Xiang, WANG Richu, ZENG Jing
DOI: 10.19976/j.cnki.43-1448/TF.2023067
In order to achieve precise control and free design of pore structure and size in porous SiC ceramics, based on the direct-ink writing of SiC porous ceramics, the effects of dispersant type and content, pH value, solid phase volume fraction, and thickener on the rheological properties of SiC slurry were studied, and then 3D porous structured SiC ceramics with controllable pore structure and size were prepared using the optimized slurry. The results indicate that the viscosity of slurry decreases first and then increases with the increment of the content of dispersant tetramethylammonium hydroxide (TMAH); pH value greater than 10 is conducive to reducing the viscosity of the slurry; the viscosity of slurry increases first and then decreases with the increment of solid phase volume fraction, having a maximum achievable solid volume fraction of 60%; the yield stress of the slurry continuously increases with increasing the addition of methyl cellulose (MC) as thickener. Optimized SiC slurry is obtained with TMAH mass fraction of 0.4%, pH value >10, solid phase volume fraction of 60%, and MC mass fraction of 0.06%. The SiC porous ceramics produced by using the slurry and direct-ink writing exhibit the advantages of high structural integrity and low drying shrinkage rate.
2023 Vol. 28 (6): 580-586 [
Abstract
] (
292
)
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596
)
587
Effects of adding Al-Mg-Sc-Zr alloy on microstructure and properties of boron carbide prepared by hot press sintering
XU Xuejun, XU Zhiwei, YUAN Tiechui, ZHOU Xiangxing
DOI: 10.19976/j.cnki.43-1448/TF.2023071
B
4
C composite ceramics were prepared by hot press sintering process with pure B
4
C powder and atomized Al-Mg-Sc-Zr alloy powder as raw materials mixed by ball milling method. The effects of sintering temperature and the addition of Al-Mg-Sc-Zr alloy on the microstructure, hardness, bending strength, and fracture toughness of the ceramics were investigated. The results show that Al-Mg-Sc-Zr alloy transforms into liquid phase at high temperature, and reacts with free C and B
4
C during sintering, which promotes sintering of ceramics and reduces porosity. With the increase of sintering temperature, the relative density of B
4
C composite ceramics increases, which can reach 99.6% when sintering at 2 100 ℃. The addition of Al-Mg-Sc-Zr alloy improves the mechanical properties of B
4
C composite ceramics, the hardness (HV), bending strength, and fracture toughness of the ceramics sintered at 2 100 ℃ increase to 3 859, (423.7±12.4) MPa, and 4.45 MPa·m
1/2
, respectively.
2023 Vol. 28 (6): 587-595 [
Abstract
] (
219
)
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461
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