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2022 Vol. 27, No. 3
Published: 2022-06-15
Engineering and Technology
Theoretical Research
Review
Review
237
Research progress on preparation and characterization of one-dimensional carbides nanomaterials
DU Jun, CAI Mingzhu, YAN Shijing, SUN Qingcheng, YIN Cailiu
DOI: 10.19976/j.cnki.43-1448/TF.2021112
One-dimensional carbides nanomaterials are widely used as superconducting materials, high temperature coating materials, cutting tool materials, supertoughening materials due to their high strength, high hardness, high chemical stability, low electrical resistivity and high oxidation corrosion resistance. Combined with the existing research progress of one-dimensional carbide nanomaterials, this paper focused on the synthesis method, growth mechanism, microstructure, performance characteristics and other aspects of the materials, and prospected the development space of this field. It is expected to provide reference for the research, development and application of one-dimensional carbide nanomaterials.
2022 Vol. 27 (3): 237-245 [
Abstract
] (
1235
)
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1496
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Theoretical Research
246
Thermodynamic investigation on the Pd-X(X=Ag, Ni, Sn) systems of the precious metals
LIAO Lin, LIU Shuhong, DU Yong
DOI: 10.19976/j.cnki.43-1448/TF.2022003
Based on the critical re-assessment on the phase diagram and thermodynamic data available in literature of the Pd-X(X=Ag, Ni, Sn) systems, Gibbs energies of the liquid and FCC_A1 phases in three binary systems were described by the substitutional solution model. Three phase, PdSn
2
, PdSn
3
and PdSn
4
,were described by the sublattice model of (Pd,Sn)
1
Sn
2
, (Pd)
0.25
(Pd,Sn)
0.75
, and (Pd)
0.2
(Pd,Sn)
0.8
, respectively. Thermodynamic parameters for the Pd-X(X=Ag, Ni, Sn) systems were then obtained by the CALPHAD (calculation of phase diagram) approach. The presently obtained thermodynamic parameters can describe the measured phase diagram and thermodynamic properties more reasonably comparing with the previous reports, especially in the phase diagram of Pd-Ag system and enthalpies of mixing of FCC_A1 in both Pd-Ag and Pd-Ni systems, as well as the Sn-rich side of the phase diagram of the Pd-Sn system. Comprehensive comparisons between the calculated results and experimental data indicated the accuracy of the presently obtained thermodynamic parameters.
2022 Vol. 27 (3): 246-256 [
Abstract
] (
682
)
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1362
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257
Parametric design of bimodal porosity structure based on Voronoi polygons and fractals
ZHANG Yu, LIU Rutie, CHEN Jie, XIONG Xiang, LI Hao, WANG Zhubo
DOI: 10.19976/j.cnki.43-1448/TF.2022007
This research proposed a bimodal porosity structure type providing the ability to individually form evenly distributed pores of two separated sizes. A method of generating structures parametrically was provided, and a process-oriented program was developed outputting diagrams and coordinates. Iterations of tessellation module, causing geometrical self-resemblance, were further discussed from porosity, fractal dimension, lacunarity and specific surface area aspects. Technical routes were introduced for building 3D model files of large complexity in common industrial software’s object-oriented application programming interface and applications in permeability or electrochemistry simulations.
2022 Vol. 27 (3): 257-266 [
Abstract
] (
607
)
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763
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267
Composition performance design of Sn-In-Ag/Bi series low-temperature lead-free solder based on Jmatpro software
JIAO Hua, BAI Jiayu, ZHANG Jianxun, ZHAO Kang
DOI: 10.19976/j.cnki.43-1448/TF.2021076
In order to solve the problems of high production cost and low mechanical properties of Sn-In lead-free solder, the low melting point Sn-In solder alloy was selected due to the phase diagram of Sn-In alloy. The composition optimization of Sn-In solder alloy was carried out to improve the thermal properties, mechanical properties and reduce cost. The low temperature lead free solder of Sn-In-Ag/Bi with different composition ratios can be formed by adding Ag and Bi elements at Sn75. The low temperature solder composition was simulated and calculated by the material phase diagram and thermodynamic simulation software of JMatPro. The Sn alloy module was selected in the software. The phase composition, thermal properties, and mechanical properties of the lead-free solder with different composition changes can be obtained. Meanwhile, the effects of temperature and alloy content on melting point, melting range, thermal properties and mechanical properties were studied. The simulation results show that two types of low-temperature lead-free solders of Sn-In-Ag and Sn-In-Ag-Bi series have the optimized compositions of Sn75Ag3In22 and Sn75In17Ag3Bi5, respectively.
2022 Vol. 27 (3): 267-275 [
Abstract
] (
721
)
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1417
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Engineering and Technology
276
Structure and properties of Mg
x
Zn
1.8-
x
SiO
3.8
microwave ceramics with low dielectric constant
DUAN Jialu, ZHOU Ganghuai, LIU Shaojun
DOI: 10.19976/j.cnki.43-1448/TF.2022005
Mg
x
Zn
1.8-
x
SiO
3.8
(
x
=0, 0.1, 0.2, 0.3, 0.4) microwave ceramics with willemite structure were prepared by the traditional solid-phase synthesis method. The effect of Mg on crystal structure, microstructure and dielectric properties of Mg
x
Zn
1.8-
x
SiO
3.8-
x
ceramics were characterized on the basis of X-ray diffraction, raman spectroscopy, and scanning electron microscopy and vector network analyzer. The results show that the theoretical polarizability of Mg
x
Zn
1.8-
x
SiO
3.8
microwave ceramics decreases, and the relative permittivity decreases correspondingly with the increase of doping Mg amount
x
of sintering temperature at 1 300 ℃. With the increase of
x
, the average twist of oxygen tetrahedron decreases first and then increases, resulting in the temperature coefficient of resonant frequency decreasing first and then increasing. With the increase of doping amount, the symmetry of the six-membered ring composed of Zn(1)/Mg(1)O
4
, Zn(2)/Mg(2)O
4
, and SiO
4
tetrahedra increases, while the Zn(Mg)—O bond length decreases and the bond energy increases, resulting in the quality factor
Q
×
f
increases. Mg
0.4
Zn
1.4
SiO
3.8
ceramicshave excellent properties, the relative permittivity
ε
r
is about 6.2, the
Q
×
f
is about 112 100 GHz, and the resonant frequency temperature coefficient
τ
f
is about -19.2×10
-6
℃.
2022 Vol. 27 (3): 276-283 [
Abstract
] (
582
)
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284
Preparation and electrocatalytic performance of Ag@Cu
2+1
O/MWNTs catalysts towards oxygen reoxygen reduction catalyst for aluminum-air battery
YIN Liankun, ZHANG Yansong, YU Jiaxin, LUO Zhihong
DOI: 10.19976/j.cnki.43-1448/TF.2021098
Ag@Cu
2+1
O/MWNTs catalysts were prepared by one-step method with THPC as reducing agent and MWNTs as support. The structure, morphology, and composition of the catalyst were characterized by X-ray diffractometry, transmission electron microscopy, and X-ray photoelectron spectroscopy. In addition, the catalyst load and ORR performance were tested. It can be seen that the Ag and Cu
2+1
O loading (mass fraction, %) of Ag@Cu
2+1
O/MWNTs catalyst are 9.32% and 5.90%, respectively, and the average particle size of Ag@Cu
2+1
O catalyst is about 7 nm. Ag@Cu
2+1
O/MWNTs catalyzes direct four-electron oxygen reduction in alkaline medium, the half-wave potential of Ag@Cu
2+1
O/MWNTs is 0.75 V, the limit diffusion current density is close to 5.5 mA/cm
2
at 1 600 r/min and the slope of Tafel is 92 mV/dec, which is equivalent to the performance of 20%Pt/C and is more outstanding than Ag/MWNTs catalyst with 17.5%Ag loading capacity. Meanwhile, Ag@Cu
2+1
O/MWNTs has the same stability as 20%Pt/C and better resistance to methanol poisoning. When used as cathode catalyst for aluminum-air battery, Ag@Cu
2+1
O/MWNTs exhibits power density (148.7 mW/cm
2
), capacity (1 260 mAh/g) and stability which is comparable to that of 20%Pt/C.
2022 Vol. 27 (3): 284-293 [
Abstract
] (
626
)
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2917
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294
Effect of graphene introduction on properties of SiC
f
/SiC composites
WANG Xuhui, CHEN Zhaoke, LI Guowang, SU Kang, MAO Jian, XIONG Xiang
DOI: 10.19976/j.cnki.43-1448/TF.2022001
In this paper, graphene contained SiC
f
/SiC composites were prepared by a two-step process, with graphene/SiC slurry introduced by slurry brushing first, then followed a chemical vapor infiltration of SiC matrix. The effects of graphene mass fraction in the slurry on the microstructure, mechanical properties and thermal conductivity of SiC
f
/SiC composites were studied by using scanning electron microscopy, three-point bending test and laser flash apparatus. The results show that, when the mass fraction of graphene is 2%, the distribution of graphene in the slurry layer is uniformly, resulting in the highest thermal conductivity of 13.14 W/(m·K) of the composites. With the increase of the mass fraction, the distribution of graphene in the slurry layer is deteriorated, which leads to a decrease of the density and thermal conductivity of SiC
f
/SiC composites. However, although graphene begins to agglomerate at a mass fraction of 4%, the composites possess the highest flexural strength of 328.12 MPa, due to the well bonding between graphene and the SiC matrix.
2022 Vol. 27 (3): 294-301 [
Abstract
] (
563
)
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302
Preparation and mechanical properties of carbon fiber reinforced phosphate composites
YU Shijie, LI Guodong, WANG Yang, JIANG Yi
DOI: 10.19976/j.cnki.43-1448/TF.2021093
Phosphate slurries were prepared using aluminum dihydrogen phosphate solution and Al
2
O
3
/ZrO
2
. C
f
/phosphate composites with phosphate as matrix and carbon fiber as reinforcing phase were prepared by paste brushing carbon fibers-laminated needling-hot pressing-vacuum impregnation-hot pressing densification process. The microstructure and phase of the composites were characterized by scanning electron microscopy and X-ray diffraction analysis. The properties of the composites such as density, open porosity and flexural strength were measured, and the effects of Al
2
O
3
content and ZrO
2
on the green body and composites were studied. The results show the highest density of C
f
/phosphate composites reaches 2.27 g/cm
3
, and the lowest open porosity is 13.4%. The oxide content affects the mechanical properties of the composites. When
m
(Al(H
2
PO
4
)
3
):
m
(Al
2
O
3
):
m
(ZrO
2
) is 200:100:10, the average flexural strength of the composite is 122 MPa, and the flexural strength of the composite is 38 MPa after treatment at 600 ℃ for 30 min.
2022 Vol. 27 (3): 302-309 [
Abstract
] (
658
)
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310
Wet synthesis of high-density basic cobalt carbonate powder and thermodynamic analysis of Co(Ⅱ)-NH
3
-CO
3
2-
-H
2
O system
XU Wei, XIA Jie, ZHANG Kejun, HU Bin, BAI Dehong, HE Kai, YUAN Tiechui, LI Ruidi
DOI: 10.19976/j.cnki.43-1448/TF.2022040
CoCl
2
and four kinds of precipitants commonly used in industry, namely (NH
4
)
2
CO
3
, NH
4
HCO
3
, Na
2
CO
3
and NaHCO
3
, were used as raw materials to prepare basic cobalt carbonate by wet synthesis. The as-prepared basic cobalt carbonate were studied by means of lazer particle analyzer, scanning electron microscope, X-ray diffractometer and vibrating densitometer. The effects of solution pH value and NH
3
concentration on particle size, microscopic morphology, crystal structure and density of basic cobalt carbonate powder were evaluated, and the thermodynamic analysis of Co(II)-NH
3
-CO
3
2-
-H
2
O system was performed as well. The results show that the pH value and NH
3
concentration of the solution have a great influence on the complexation and precipitation behavior of cobalt ions. Based on the complexing precipitation process, the tap density of the basic cobalt carbonate solid powders prepared with NH
4
HCO
3
and (NH
4
)
2
CO
3
precipitant is higher. Based on the principle of simultaneous equilibrium and mass conservation, the thermodynamic diagram of lg[Co]
total
on pH under different solution compositions was drawn, and the effect of solution pH value of different systems on the precipitation process was further studied. The results show that the precipitation rate of cobalt ions is more than 90% when the pH is 6-8. In the Na
2
CO
3
and NaHCO
3
precipitant systems, free Co
2+
is dominant during the transient, and it precipitates rapidly after contacting the precipitant to form loose flocculated basic cobalt carbonate powders. In the (NH
4
)
2
CO
3
and NH
4
HCO
3
precipitant systems, Co
2+
is coordinated with ammonia, the precipitation process procees slowly with the release of Co
2+
from multi coordinated Co(NH
3
)
n
2+
(
n
=1, 2,…, 6), results in dense powders.
2022 Vol. 27 (3): 310-318 [
Abstract
] (
820
)
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319
Microstructure control and grain refinement mechanism of ceramic corundum abrasives prepared by sol-gel combined with two step sintering process
ZHAO Jiong, LI Zhuan, ZOU Lingfeng, TANG Huixian, XU Yang, LI Yuxing, ZOU Huijing
DOI: 10.19976/j.cnki.43-1448/TF.2022012
Ceramic corundum abrasive precursor containing La
2
O
3
-TiO
2
-SiO
2
composite additive was prepared by sol-gel method using pseudo boehmite with grain diameter of 6 μm as raw material. The ceramic corundum abrasives were prepared by conventional sintering method and two-step sintering method, respectively. The microstructure and element distribution of abrasives were analyzed by SEM and TEM, and the grain sizes were analyzed by imagePro software. The results show that the temperature of the first sintering stage significantly affects the final grain size of the abrasive when the two-step sintering method is adopted. Due to the low temperature in the second sintering stage, the later sintering mechanism changes from grain boundary migration to grain boundary diffusion, thus the grains are significantly refined and the abnormal grain grow this avoided. Appropriately reducing the sintering temperature in the second stage is conducive to obtaining fine equiaxed grains with uniform distribution, but it will lead to a decrease in abrasive density. Compared with the corundum abrasives prepared by the traditional sintering method, the abrasives prepared by the two-step sintering method have a smaller grain size, uniform size and high hardness, although the density is reduced. Fine and uniform equiaxed grains are obtained by two-step sintering at 1 300 ℃ and 1 200 ℃ for 10 h, respectively. The average grain size is (334±97) nm, and the density and hardness (HV) are 3.87 g/cm
3
and (18.3±0.29) GPa, respectively.
2022 Vol. 27 (3): 319-326 [
Abstract
] (
720
)
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1452
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327
Effects of oxidation accelerator on phosphating of iron powders and soft magnetic properties of iron powder cores
LIU Xiangyang, FU Jiaqian, YU Yongliang, LI Songlin
DOI: 10.19976/j.cnki.43-1448/TF.2022002
The effects of oxidation accelerator Na
2
MoO
4
, NaNO
2
and their compound addition on the phosphating reaction of iron powder in NaH
2
PO
4
phosphating solution were investigated using reduced iron powder as matrix powder. The structure and properties of iron powder before and after phosphating and iron powder cores were characterized by scanning electron microscopy, X-ray diffractometer, Fourier transform infrared spectrometer, vibration sample magnetometer and soft magnetic AC measuring instrument. The results show that iron powder in 5% mass fraction of NaH
2
PO
4
phosphating solution cannot form a complete and uniform coating with the rapid reaction speed. The soft magnetic loss of iron powder cores decreases, but the frequency stability of magnetic permeability is bad. The surface phosphating layer structure of iron powder phosphated by NaH
2
PO
4
is mainly composed of Fe
3
(PO
4
)
2
and FePO
4
. The addition of NaNO
2
in NaH
2
PO
4
phosphating solution promotes phosphate generation, but the coating isn’t uniform, and the coating layer is mainly composed of FePO
4
. Adding Na
2
MoO
4
or Na
2
MoO
4
+NaNO
2
composite oxidation accelerator to NaH
2
PO
4
phosphating solution can generate uniform coating layer on the surface of iron powders and greatly reduce the eddy current loss of iron powder cores. The coating layer is mainly composed of FePO
4
and Fe
2
(MoO
4
)
3
. The compound addition of Na
2
MoO
4
+NaNO
2
compound addition has the best improvement effect on phosphating reaction. After heat treatment at 400 ℃, the resistivity of iron powder cores is 194.2 μΩ∙m, under the condition of
B
m
=50 mT,
f
=100 kHz, the magnetic permeability of iron cores is 92.5, and the soft magnetic loss is 142.0 W/kg.
2022 Vol. 27 (3): 327-335 [
Abstract
] (
698
)
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336
Preparation and characterization of micron hollow silica microspheres
WEN Sufen, ZOU Jinzhu, ZHOU Xuefan, LUO Hang
DOI: 10.19976/j.cnki.43-1448/TF.2022015
The hollow SiO
2
microspheres were prepared through the hard template method and sol-gel method by using self-made polystyrene (PS) as template, cetyltrimethyl ammonium bromide (CTAB) as cationic surfactant and Tetraethyl orthosilicate (TEOS) as silica source. Effects of heating rate, content of CTAB, TEOS and ammonia on the morphology of hollow SiO
2
microspheres were discussed. The phase, morphology and mesoporous structure of hollow SiO
2
microspheres were characterized by XRD, TEM, SEM, TG and FTIR, which shows the successful preparation of hollow silica sphere. The particle sizes of hollow SiO
2
microspheres are 2-5 μm and the thickness is 117 nm. The hollow SiO
2
microsphere wall damage with the increase of heating rate. With increasing CTAB content, the number of nanospheres increase and the particle sizes of nanospheres decrease. With increasing TEOS content, the thicknesses of spheres increase until nanospheres are formed. When ammonia is less than 4 mL, hollow SiO
2
microsphere cannot be formed. When ammonia is greater than 4 mL, hollow SiO
2
microsphere have rough surface with solid particles. The optimized conditions are determined as follows: the heating rate is 0.5 ℃/min, the amount of CTAB is 0.05 g, the amount of TEOS is 0.3 mL, the amount of ammonia is 4 mL and then hollow SiO
2
microspheres are treated through filtering and cleaning.
2022 Vol. 27 (3): 336-344 [
Abstract
] (
1950
)
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(1 KB)
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3824
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