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2019 Vol. 24, No. 5
Published: 2019-10-15
Engineering and Technology
Theoretical Research
391
Metal hydride thermal energy storage and its research progress
ZHOU Chengshang, LIU Huang, LIU Yong, SHI Quan
In the past decades, metal hydrides have attracted extensive attention as high-energy-density thermal storage materials. This paper introduces the thermochemical properties of metal hydrides and the working principle of the metal hydride-based thermal storage systems. Based on recent research progresses and developments, the working temperature, pressure and heat storage density of metal hydride as heat storage materials at high, medium and low temperature were analyzed and discussed. The application and development trend of refrigeration and heat pump for metal hydride thermal energy storage were also discussed.
2019 Vol. 24 (5): 391-399 [
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] (
920
)
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1869
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Engineering and Technology
400
Preparation and tribological properties of plasma cladding Fe-Cr-Nb-Si-Mo coatings
XING Yadong, GAO Guijun, LI Xinxin
Three kinds of wear-resistant coatings A1, A2 and A3 were prepared by plasma arc cladding Fe-Cr-Nb-Si-Mo alloy powder coating on the common materials of the monorail crane friction drive wheel WH60A, Weartuf450 and NM450. The composition, friction and wear properties and bonding strength of the three coating phases were tested and analyzed by metallographic microscope, X-ray diffractometer, microhardness tester and hydraulic universal material testing machine. The results show that the main phases of A1, A2 and A3 are martensite and various metal carbides ((Nb,Mo)C,VC,Cr
7
C
3
), and the Vickers hardness of the surface of WH60A is increased by 790.4 HV
0.1
. The hardness of the substrate Weartuf450 and NM450 increased from 467.8, 493.4 HV
0.1
to 1 002.1, 983.3 HV
0.1
, respectively; the friction coefficient and wear rate of the Weartuf450 surface cladding layer are the largest compared with the other two substrates.
2019 Vol. 24 (5): 400-405 [
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] (
658
)
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1123
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406
Finite element simulation study on the process of tungsten-copper powder rolling
CUI Liqun, HAN Shengli, SHI Qi, LI Daren, HU Jianzhao, LIU Zuyan
The Drucker-Prager/Cap model was used to describe the rolling deformation of tungsten-copper powders,and the corresponding finite element model was established. The effects of processing paramenters, including roll gap, rolling speed and rolling temperature on the relative density of sheets were studied using the finite element analysis software (Abaqus). The simulation results were compared with the experimental ones. The results show that in the process of tungsten-copper alloy powder rolling, the larger the gap between rolls, the smaller the relative density of the rolled sheet and the more uniform the density distribution. With increasing rolling speed, the relative density of the sheet decreases, the low density area of the edge decreases, and the uniformity of the density distribution increases. The higher the rolling temperature is, the higher the relative density of the sheet is and the better the powder fluidity is. Comparing the simulation results with the experimental results, the maximum error is 4.1%, which indicates the reliability of the finite element model.
2019 Vol. 24 (5): 406-412 [
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682
)
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(546 KB) (
605
)
413
Corrosion performance of Ta-10W coating on titanium and its alloy by multi-arc ion plating
SUN Pei, GU Yi, LI Yaqi, LIU Baoshan
To improve the corrosion performance of titanium and titanium alloy in human body and Marine environment,the Ta-10W coating was prepared on the commercial pure titanium (CP-Ti) and TC4 matrix by multi-arc ion plating. The corrosion resistance of the coating in simulated human body and Marine environment was studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), electrodynamic polarization and electrochemical impedance spectroscopy (EIS) test. The results show that the Ta-10W coating is continuous, dense with uniform thickness. The mainly phase is body-centered cubic α-Ta. Ta-10W coated samples corrosion potential is higher and corrosion current density is lower in ringer solution and simulated seawater solution. The Ta-10W coating on CP-Ti reduces the corrosion current density to 2.648×10
-9
A/cm
2
in ringer solution and 2.548×10
-9
A/cm
2
in simulated seawater solution, which is an order of magnitude lower than that of CP-Ti matrix, and also has excellent improvements on TC4 matrix. In addition, Ta-10W increases the charge transfer resistance of CP-Ti and TC4 by 1 or 2 orders of magnitude in the two solutions. The dielectric property of the double layer is also improved by coating Ta-10W, thus the corrosion resistance of CP-Ti and TC4 in different solution environments is effectively improved. Therefore, Ta-10W coating has a good protective effect on the corrosion resistance of CP-Ti and TC4 in human body and marine environment, and is instructive for the application of titanium and titanium alloy in these environments.
2019 Vol. 24 (5): 413-421 [
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] (
720
)
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1577
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422
Effects of selective laser melting processing parameters on the densification and mechanical properties of Fe20Cr5Al alloy
LU Yang, ZHAO Zhe, MIING Liang, HU Zijian, XUE Xiangyuan, DENG Xin, LIU Jianye, QI Wenjun, NIU Liuhui, GAO Wenhua
Fe20Cr5Al alloy vehicle exhaust purifier material was fabricated by 3D printing based on selective laser melting (SLM) forming technology. The relationship between printer parameters (laser power, scanning speed and scanning spacing) and the density of printed parts were systematically studied by using response surface experimental design. The relationship model between SLM forming parameters and density and the relationship model between printer parameters and mechanical properties were obtained, and the optimum SLM forming parameters were obtained. The results show that the effects of SLM process parameters on the density of printed parts are in the order of laser power, scanning speed and scanning spacing. The optimum SLM forming parameters are laser power of 314.8 W, scanning speed of 1 700 mm/s and scanning distance of 0.06 mm. The predicted relative density under this process parameter is 99.74%, and the average error with the SLM forming experiment result is only 0.16%. The model has high reliability, and the average actual relative density under the optimized process parameter is 99.58%. the tensile strength is 616.44 MPa, and the elongation is 1.513%.
2019 Vol. 24 (5): 422-429 [
Abstract
] (
621
)
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(473 KB) (
1400
)
430
Microstructure and properties of TiC
p
/M2 powder metallurgical high speed steel
LONG Xuehu, TENG Hao, LI Zhiyou
High-energy ball milled M2 high speed steel powders reinforced with 6%Mo
2
C and 3%-12%TiC have been cold-pressed and subsequently sintered at 1 030-1 240 ℃ under vacuum to obtain TiC particle reinforced M2 powder high speed steel composites (TiC
P
/M2). The phase, microstructure and properties of sintered TiC
p
/M2 high speed steel were tested and analyzed by X-ray diffractometer, scanning electron microscopy and universal material testing machine. The results show that the mixed powders have higher sintering activity, and all samples can be fully densified when sintered below 1 220 ℃. The addition of TiC will hinder the densification process of high speed steel. Compared with 3%TiC
p
/M2, the sintering temperature of 12%TiC
p
/M2 increases by about 40 K. TiC can promote the formation of MC carbides. With the increase of sintering temperature, the volume fraction of TiC decreases, while the size and volume fraction of MC carbides increase. The hardness of TiC
P
/M2 high speed steel increases with increasing TiC content. At the optimum sintering temperature, the hardness (HRC) increases from 58.3 to 62.1 with the increase of TiC content from 3% to 12%, respectively. The bending strength of high speed steel increases first and then decreases with increasing TiC content. The highest bending strength of 9%TiC/M2 is 2 358 MPa. The addition of TiC can widen the sintering temperature range of M2 high speed steel to a certain extent.
2019 Vol. 24 (5): 430-436 [
Abstract
] (
705
)
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763
)
437
Preparation and characterization of tubular porous loess ceramic membrane support
MENG Feng, YANG Bowen, TONG Zhi, XING Jing, SUN Xiaojuan, WANG Lei
The new single-tube loess ceramic membrane supports were fabricated by rolling and sintering from α-Al
2
O
3
as the external aluminum source, MgO as the sintering aid, CMC as pore former and loess as aggregate. In this work, the orthogonal experiment was designed to study the effect of α-Al
2
O
3
, MgO and CMC on the performance of the support. The results show that the order of factors affecting the water permeability of the support is CMC>α-Al
2
O
3
>MgO, and the order of factors affecting the bending strength of the support is α-Al
2
O
3
>CMC>MgO. When adding mass fraction of 15% α-Al
2
O
3
, 6%CMC, 0.5%MgO, the support prepared by holding for 3 h at 1 180 ℃ has the best performance, the flexural strength is 55.66 MPa, and the porosity is 28.7%, pure water flux is 83.63 m
3
/(m·h·bar), and the median pore size is 19.88 μm, in which the main peak pore volume accounts for more than 95% of the total pore volume, and the main peak pore size distribution ranges from 8.54-52.23 μm. The pore size distribution range is wide with a porosity of 28.7%. The main crystalline phases are quartz, feldspar, mullite, cordierite and cristobalite.
2019 Vol. 24 (5): 437-443 [
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] (
356
)
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728
)
444
Effects of annealing treatment on microstructure and properties of CrFeCoNiTi
0.2
high-entropy alloys prepared by powder metallurgy
JIANG Yue, ZHOU Guangtai, LI Xiuming, CHENG Simeng
The CrFeCoNiTi
0.2
high-entropy alloy was prepared by powder metallurgy and was annealed at 450, 650 and 850 ℃. X-ray diffraction analysis, scanning electron microscopy, energy spectrum analysis, dynamic potential polarization curves and micro Vickers hardness test were conducted to study the effect of annealing treatment on microstructure and properties of powder metallurgy CrFeCoNiTi
0.2
high entropy alloy. The results show that the sintered CrFeCoNiTi
0.2
high-entropy alloy has FCC as the main phase and Laves phase as the secondary phase. After annealing, the crystallinity of the FCC phase increases, with the presence of new phases (HCP phase, R phase, σ phase). The self-corrosion potential
E
corr
and the vickers hardness of the alloy both increase, and the higher the annealing temperature, the better the corrosion resistance and the higher the hardness. After annealing at 850 ℃, the vickers hardness (HV) of the alloy increases from 184 to 356.6.
2019 Vol. 24 (5): 444-451 [
Abstract
] (
444
)
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1361
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452
Characterization and photocatalytic properties of Ag/Ag
1.69
Sb
2.27
O
6.25
photocatalytic nano-powder synthesized by ion exchange method
ZHENG Zhihe, HUNG Linjun, ZHANG Ning
Ag/Ag
1.69
Sb
2.27
O
6.25
photocatalytic nano-powders were synthesized by ion exchange method using K
2
H
2
Sb
2
O
7
·4H
2
O and AgNO
3
as raw materials. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, ultraviolet diffuse reflectance and ultraviolet-visible-spectrophotometer were used to analyze and test the phase, morphology, structure and optical properties of the nano-powders obtained at different calcination temperatures. The photocatalytic properties of the nano-powders were measured by photodegradation experiments of tetracycline hydrochloride (TC-HCl) under visible light. The results show that the diameter of Ag/Ag
1.69
Sb
2.27
O
6.25
particles is about 100-150 nm, and the surface of Ag
1.69
Sb
2.27
O
6.25
is coated with spherical Ag particles with a size of 10 nm. With the increase of calcination temperature, the depression of Ag/ Ag
1.69
Sb
2.27
O
6.25
nanoparticles becomes smaller, and the powder color changes from gray to yellow. The photocatalytic activity of Ag/ Ag
1.69
Sb
2.27
O
6.25
nano-materials prepared at 250 ℃ is the highest, which is 7 times higher than that of the materials (Ag/ASO-250) prepared at 900 ℃. Moreover, the percentage of TC-HCl degradation by AgSbO
3
-ssr, N-TiO
2
and Ag/ASO-250 is 65%, 77%, and 90% respectively when the photocatalytic degradation reaction lasts 90 minutes. This indicates that Ag/ASO-250 has strong photocatalytic activity compared with AgSbO
3
-ssr and N-TiO
2
.
2019 Vol. 24 (5): 452-458 [
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] (
343
)
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(1 KB)
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(1277 KB) (
1201
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459
Tribological properties of Fe-5(Cu-10Sn)-graphite-P-MoS
2
oil-containing materials
QIU Tianxu, ZHANG Jifeng, SUN Lu, WAN Lin, SHEN Xiaoping
Fe-5(Cu-10Sn)-graphite-P-MoS
2
oil-containing materials were prepared by powder metallurgy. The effects of graphite, P and MoS
2
contents on the tribological properties of the material were studied. The friction tests were carried out at 150 ℃ (±10 ℃) with linear velocity of 0.25, 0.50 and 0.75 m/s. The loading ranges from 10 MPa to 50 MPa, which increasing by 10 MPa every 10 minutes. The results show that the friction coefficient of the material decreases with the increase of C content. When the C content reaches 1.5%, the friction coefficient is basically stable at a lower value. The addition amount of P is preferably 0.3%, and both lower and higher results in unstable friction coefficient of the material. The friction coefficient of the material decreases with the increase of MoS
2
content. When the MoS
2
content is 1.5%, the material has a stable friction coefficient, and the friction coefficient shows a steady decrease with the increase of load and linear velocity.
2019 Vol. 24 (5): 459-466 [
Abstract
] (
332
)
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(1 KB)
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(686 KB) (
494
)
467
Preparation, characterization and electrochemical hydrogen evolution of MOF-derived CoP/C
HUANG Linjun, CAO Xinxin, ZHENG Zhihe, TANG Yan, LIANG Shuquan
Carbon-coated cobalt phosphide (CoP/C) powders were prepared by high temperature pre-annealing and further phosphating using Zeolitic Imidazolate Framework-67 (ZIF-67) and Co(NO
3
)
2
∙6H
2
O as precursor. CoP/C powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), and the electrocatalytic hydrogen evolution experiments were also carried out. The results show that after calcination at high temperature, the organic components of ZIF-67 are transformed into conductive carbon skeleton, and cobalt ions are transformed into elemental cobalt nanoparticles embedded in the carbon skeleton. After further phosphating, pure phase CoP/C powders are obtained. CoP/C powders exhibit good catalytic activity with an overpotential of 64 mV and a Tafel slope of 66 mV/dec, which maintains high catalytic activity after 15 h for electrocatalytic hydrogen evolution.
2019 Vol. 24 (5): 467-473 [
Abstract
] (
435
)
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(1 KB)
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(908 KB) (
5159
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474
Microstructure and damping properties of B
4
C particle reinforced Mg composites for motor fabricated by reactive infiltration method
QI Guanran
Using B
4
C particles and Mg ingot as raw materials, B
4
C/Mg composites with 30% B
4
C mass fraction for motor were prepared by reactive infiltration method. The micro structure and damping properties of materials prepared at different temperatures were analyzed and tested. The results show that the irregular B
4
C particles are evenly distributed in the matrix of B
4
C/Mg composites, and no macroscopic holes are formed. A white layer of carbide and boride is formed at the edge of B
4
C particles. Compared with the Mg matrix, the damping performance of B
4
C/Mg composite is significantly improved. With the increase of strain amplitude, the damping property of B
4
C/Mg composite material shows a change rule of slow increase first and then rapid increase. The lower the preparation temperature, the better the damping property of the material. The Cranato-lucke curve varies linearly in the amplitude of finite strain.
2019 Vol. 24 (5): 474-477 [
Abstract
] (
430
)
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(1 KB)
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(449 KB) (
740
)
478
Properties of three-dimensional (3D) graphene-reinforced copper matrix composites by powder metallurgy method
YI Chunqiang, YIN Cailiu, LIU Chunxuan, WEN Guofu, WANG Xiufei
The 0-0.4% (mass fraction) 3D graphene was added as a reinforcement in Cu-5%Sn alloy. The 3D graphene/Cu-5%Sn composites were prepared via powder metallurgy method. The density, resistivity, tensile strength, impact strength, Brinell hardness and friction and wear properties were measured. The results show that with increasing 3D graphene content, the density and tensile strength of 3D graphene/Cu-5%Sn composites decrease, and the resistivity increase slightly, the wear value increases. As the braking speed increases, the friction coefficient decreases. The composite with 0.4% graphene has the best stable friction coefficient. Compared with Cu-5%Sn matrix, when the content of 3D graphene is 0.2%, the maximum impact strength is 32.5 J/cm
2
,which is increased by 57.0%. When the content of 3D graphene is 0.1%, the Brinell hardness (HBW) and elongation are 122.0 and 11.52%, respectively, which is increased by 22.0% and 10.5% for Cu-5%Sn alloy. The fracture morphology of composite appears a dimple pattern with typical features of plastic fracture.
2019 Vol. 24 (5): 478-484 [
Abstract
] (
534
)
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(1 KB)
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(1393 KB) (
1037
)
485
Effect of TiO
2
content on properties of loess ceramic membrane support
SHEN Zao, ZHOU Guangrui, TONG Zhi, WANG Jiayue, YAN Xiao
Taking Luochuan loess with an average particle size of 38.78 μm as the aggregate, lignocellulosic (LCS) as pore former and binder, titanium dioxide (TiO
2
) as the sintering assistant, the rolling molding method was used to prepare the tubular porous loess ceramic support, which were characterized by pure water flux, flexural strength, acid/alkali resistance, analysis of crystal phase composition and observation of surface morphology. The effects of TiO
2
content on the properties of the ceramic membrane support were investigated. The results show that the addition of TiO
2
can promote the sintering and densification of loess ceramic membrane support. When the sintering temperature is 1 050 ℃ and TiO
2
content is 4%, the flexural strength is 31.97 MPa, the pure water flux is 3 487.27 L/(m
2
·h·MPa), the porosity is 33.48%, the average pore size is 3.14 μm, the mass loss rate of acid/alkali corrosion is only 0.14% and 0.13%, and the surface of the support has a uniform grain size and more micropores.
2019 Vol. 24 (5): 485-490 [
Abstract
] (
346
)
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(1 KB)
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(447 KB) (
684
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