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1.
Justyna Zygmuntowicz Radosaw urowski Justyna Tomaszewska Marcin Wachowski Janusz Torzewski Paulina Piotrkiewicz Micha Gloc Katarzyna Konopka 《Materials》2021,14(9)
The present work deals with the evaluation of the effect of ZrO2 on the structure and selected properties of shapes obtained using the centrifugal slip casting method. The samples were made of alumina and zirconia. The applied technology made it possible to produce tubes with a high density reaching 99–100% after sintering. Very good bonding was obtained at the Al2O3/ZrO2 interphase boundaries with no discernible delamination or cracks, which was confirmed by STEM observations. In the case of Al2O3/ZrO2 composites containing 5 vol.% and 10 vol.% ZrO2, the presence of equiaxial ZrO2 grains with an average size of 0.25 µm was observed, which are distributed along the grain boundaries of Al2O3. At the same time, the composites exhibited a very high hardness of 22–23 GPa. Moreover, the environmental influences accompanying the sintering process were quantified. The impacts were determined using the life cycle analysis method, in the phase related to the extraction and processing of raw materials and the process of producing Al2O3/ZrO2 composites. The results obtained show that the production of 1 kg of sintered composite results in greenhouse gas emissions of 2.24–2.9 kg CO2 eq. which is comparable to the amount of emissions accompanying the production of 1 kg of Polyvinyl Chloride (PVC), Polypropylene (PP), or hot-rolled steel products. 相似文献
2.
Katarzyna Konopka Marek Krasnowski Justyna Zygmuntowicz Konrad Cymerman Marcin Wachowski Paulina Piotrkiewicz 《Materials》2021,14(12)
The paper describes an investigation of Al2O3 samples and NiAl–Al2O3 composites consolidated by pulse plasma sintering (PPS). In the experiment, several methods were used to determine the properties and microstructure of the raw Al2O3 powder, NiAl–Al2O3 powder after mechanical alloying, and samples obtained via the PPS. The microstructural investigation of the alumina and composite properties involves scanning electron microscopy (SEM) analysis and X-ray diffraction (XRD). The relative densities were investigated with helium pycnometer and Archimedes method measurements. Microhardness analysis with fracture toughness (KIC) measures was applied to estimate the mechanical properties of the investigated materials. Using the PPS technique allows the production of bulk Al2O3 samples and intermetallic ceramic composites from the NiAl–Al2O3 system. To produce by PPS method the NiAl–Al2O3 bulk materials initially, the composite powder NiAl–Al2O3 was obtained by mechanical alloying. As initial powders, Ni, Al, and Al2O3 were used. After the PPS process, the final composite materials consist of two phases: Al2O3 located within the NiAl matrix. The intermetallic ceramic composites have relative densities: for composites with 10 wt.% Al2O3 97.9% and samples containing 20 wt.% Al2O3 close to 100%. The hardness of both composites is equal to 5.8 GPa. Moreover, after PPS consolidation, NiAl–Al2O3 composites were characterized by high plasticity. The presented results are promising for the subsequent study of consolidation composite NiAl–Al2O3 powder with various initial contributions of ceramics (Al2O3) and a mixture of intermetallic–ceramic composite powders with the addition of ceramics to fabricate composites with complex microstructures and properties. In composites with complex microstructures that belong to the new class of composites, in particular, the synergistic effect of various mechanisms of improving the fracture toughness will be operated. 相似文献
3.
Paola Palmero Giovanni Pulci Francesco Marra Teodoro Valente Laura Montanaro 《Materials》2015,8(2):611-624
An Al2O3/5 vol%·ZrO2/5 vol%·Y3Al5O12 (YAG) tri-phase composite was manufactured by surface modification of an alumina powder with inorganic precursors of the second phases. The bulk materials were produced by die-pressing and pressureless sintering at 1500 °C, obtaining fully dense, homogenous samples, with ultra-fine ZrO2 and YAG grains dispersed in a sub-micronic alumina matrix. The high temperature mechanical properties were investigated by four-point bending tests up to 1500 °C, and the grain size stability was assessed by observing the microstructural evolution of the samples heat treated up to 1700 °C. Dynamic indentation measures were performed on as-sintered and heat-treated Al2O3/ZrO2/YAG samples in order to evaluate the micro-hardness and elastic modulus as a function of re-heating temperature. The high temperature bending tests highlighted a transition from brittle to plastic behavior comprised between 1350 and 1400 °C and a considerable flexural strength reduction at temperatures higher than 1400 °C; moreover, the microstructural investigations carried out on the re-heated samples showed a very limited grain growth up to 1650 °C. 相似文献
4.
Katarzyna Konopka Justyna Zygmuntowicz Marek Krasnowski Konrad Cymerman Marcin Wachowski Paulina Piotrkiewicz 《Materials》2022,15(2)
NiAl-Al2O3 composites, fabricated from the prepared composite powders by mechanical alloying and then consolidated by pulse plasma sintering, were presented. The use of nanometric alumina powder for reinforcement of a synthetized intermetallic matrix was the innovative concept of this work. Moreover, this is the first reported attempt to use the Pulse Plasma Sintering (PPS) method to consolidate composite powder with the contribution of nanometric alumina powder. The composite powders consisting of the intermetallic phase NiAl and Al2O3 were prepared by mechanical alloying from powder mixtures containing Ni-50at.%Al with the contribution of 10 wt.% or 20 wt.% nanometric aluminum oxide. A nanocrystalline NiAl matrix was formed, with uniformly distributed Al2O3 inclusions as reinforcement. The PPS method successfully consolidated NiAl-Al2O3 composite powders with limited grain growth in the NiAl matrix. The appropriate sintering temperature for composite powder was selected based on analysis of the grain growth and hardness of Al2O3 subjected to PPS consolidation at various temperatures. As a result of these tests, sintering of the NiAl-Al2O3 powders was carried out at temperatures of 1200 °C, 1300 °C, and 1400 °C. The microstructure and properties of the initial powders, composite powders, and consolidated bulk composite materials were characterized by SEM, EDS, XRD, density, and hardness measurements. The hardness of the ultrafine-grained NiAl-Al2O3 composites obtained via PPS depends on the Al2O3 content in the composite, as well as the sintering temperature applied. The highest values of the hardness of the composites were obtained after sintering at the lowest temperature (1200 °C), reaching 7.2 ± 0.29 GPa and 8.4 ± 0.07 GPa for 10 wt.% Al2O3 and 20 wt.% Al2O3, respectively, and exceeding the hardness values reported in the literature. From a technological point of view, the possibility to use sintering temperatures as low as 1200 °C is crucial for the production of fully dense, ultrafine-grained composites with high hardness. 相似文献
5.
Kunyang Fan Wenhuang Jiang Jesús Ruiz-Hervias Carmen Baudín Wei Feng Haibin Zhou Salvador Bueno Pingping Yao 《Materials》2021,14(24)
A series of Al2O3–Al2TiO5 ceramic composites with different Al2TiO5 contents (10 and 40 vol.%) fabricated at different sintering temperatures (1450 and 1550 °C) was studied in the present work. The microstructure, crystallite structure, and through-thickness residual stress of these composites were investigated by scanning electron microscopy, X-ray diffraction, time-of-flight neutron diffraction, and Rietveld analysis. Lattice parameter variations and individual peak shifts were analyzed to calculate the mean phase stresses in the Al2O3 matrix and Al2TiO5 particulates as well as the peak-specific residual stresses for different hkl reflections of each phase. The results showed that the microstructure of the composites was affected by the Al2TiO5 content and sintering temperature. Moreover, as the Al2TiO5 grain size increased, microcracking occurred, resulting in decreased flexure strength. The sintering temperatures at 1450 and 1550 °C ensured the complete formation of Al2TiO5 during the reaction sintering and the subsequent cooling of Al2O3–Al2TiO5 composites. Some decomposition of AT occurred at the sintering temperature of 1550 °C. The mean phase residual stresses in Al2TiO5 particulates are tensile, and those in the Al2O3 matrix are compressive, with virtually flat through-thickness residual stress profiles in bulk samples. Owing to the thermal expansion anisotropy in the individual phase, the sign and magnitude of peak-specific residual stress values highly depend on individual hkl reflection. Both mean phase and peak-specific residual stresses were found to be dependent on the Al2TiO5 content and sintering temperature of Al2O3–Al2TiO5 composites, since the different developed microstructures can produce stress-relief microcracks. The present work is beneficial for developing Al2O3–Al2TiO5 composites with controlled microstructure and residual stress, which are crucial for achieving the desired thermal and mechanical properties. 相似文献
6.
Justyna Zygmuntowicz Katarzyna Konopka Marek Krasnowski Paulina Piotrkiewicz Jan Bolek Marcin Wachowski Radosaw urowski Mikoaj Szafran 《Materials》2022,15(8)
This work aimed to characterize Al2O3 matrix composites fabricated by the slip casting method using NiAl-Al2O3 composite powder as the initial powder. The composite powder, consisting of NiAl + 30 wt.% Al2O3, was obtained by mechanical alloying of Al2O3, Al, and Ni powders. The composite powder was added to the Al2O3 powder to prepare the final powder for the slip casting method. The stained composite samples presented high density. EDX and XRD analyses showed that the sintering process of the samples in an air atmosphere caused the formation of the NiAl2O4 spinel phase. Finally, the phase composition of the composites changed from the initial phases of Al2O3 and NiAl to Al2O3, Ni, and NiAl2O4. However, in the area of Ni, fine Al2O3 particles remaining from the initial composite powder were visible. It can be concluded that after slip casting, after starting with Al2O3 and the composite powder (NiAl-Al2O3) and upon sintering in air, ceramic matrix composites with Ni and NiAl2O4 phases, complex structures, high-quality sintered samples, and favorable mechanical properties were obtained. 相似文献
7.
Varuna Jayachandran Vishnu Shankar Dhandapani Elango Muniappan Dongkyou Park Byungki Kim A. P. Arun P. R. Ayyappan 《Materials》2022,15(23)
In order to control diesel exhaust emission, CeO2-SnO2/Al2O3 (CTA) mixed oxides were prepared and coated on perforated stainless steel (SS) filter plates, and the catalytic activities were analyzed in this work. The CeO2-SnO2 (different compositions of Ce/Sn—2:8; 1:1; 8:2) composites and Al2O3 were prepared separately via a co-precipitation approach, and CeO2-SnO2/Al2O3 (CTA) mixed oxides were attained by mechanical mixing of 75 wt% CeO2-SnO2 composites with 25 wt% Al2O3. X-ray diffraction (XRD) and Raman spectroscopy were performed for all three CeO2-SnO2/Al2O3 (CTA) mixed oxides; the CeO2-SnO2/Al2O3 (Ce/Sn-1:1) sample confirmed the presence of cubic and tetragonal mixed faces, which enhances the redox nature (catalytic activities). Various characterizations such as high-resolution transmission electron microscopy (HRTEM), Brunauer–Emmett–Teller (BET) analysis, X-ray photoelectron spectroscopy (XPS), and a scanning electron microscope (SEM) were employed on CeO2-SnO2/Al2O3 (Ce/Sn-1:1) sample to investigate the structural, textural, compositional, and morphological properties. The CeO2-SnO2/Al2O3 (Ce/Sn-1:1) sample was coated on a perforated stainless steel (SS) filter plate via a simple, cost-effective, and novel method, and an exhaust emission test for various compression ratios (CR), injection pressure (IP), and load (L) was completed using an AVL Digas analyzer. The CeO2-SnO2/Al2O3 (Ce/Sn-1:1) sample, with a size of 10.22 nm and a high surface area of about 73 m2 g−1, exhibit appreciable catalytic properties. 相似文献
8.
Silicon-based anodes can increase the energy density of Li-ion batteries (LIBs) owing to their large weights and volumetric capacities. However, repeated charging and discharging can rapidly deteriorate the electrochemical properties because of a large volume change in the electrode. In this study, a commercial Fe-Si powder was coated with Al2O3 layers of different thicknesses via atomic layer deposition (ALD) to prevent the volume expansion of Si and suppress the formation of crack-induced solid electrolyte interfaces. The Al2O3 content was controlled by adjusting the trimethyl aluminum exposure time, and higher Al2O3 contents significantly improved the electrochemical properties. In 300 cycles, the capacity retention rate of a pouch full-cell containing the fabricated anodes increased from 69.8% to 72.3% and 79.1% depending on the Al2O3 content. The powder characterization and coin and pouch cell cycle evaluation results confirmed the formation of an Al2O3 layer on the powder surface. Furthermore, the expansion rate observed during the charging/discharging of the pouch cell indicated that the deposited layer suppressed the powder expansion and improved the cell stability. Thus, the performance of an LIB containing Si-alloy anodes can be improved by coating an ALD-synthesized protective Al2O3 layer. 相似文献
9.
Rui Yang Kuiwu Li Likui Yin Kai Ren Yu Cheng Taotao Li Jianping Fu Taiyong Zhao Zhigang Chen Jinlong Yang 《Materials》2022,15(8)
This work aims to improve the penetration ability of a 14.5 mm standard armor-piercing projectile into ceramic/armor steel (Al2O3/RHA) composite armor. To this end, ZrO2 toughened Al2O3(ZTA) is prepared as the material for bullet tips, utilizing in situ solidification injection molding that is realized via ceramic dispersant hydrolytic degradation. The penetration power of ZTA ceramic composite projectile, compared with standard armor, against 15 mm armor steel (RHA) and 30 mm Al2O3/RHA composite armor, is studied by ballistics testing combined with numerical simulation. The Tate theory is optimized and then employed to calculate the penetration depth and bullet core’s residual mass when ZTA ceramic composite projectile penetrates into Al2O3/RHA composite armor. The results show that when penetrating RHA of 15 mm, the penetration area of ZTA ceramic composite projectile into RHA increases by 27.59% and the exit area by 42.93%. While the standard projectile fails to penetrate the 30 mm Al2O3/RHA composite armor, the ZTA ceramic composite armor-piercing projectile succeeds, with the mass loss reduced by 66.67% over the standard one. The ZTA ceramic composite bullet has a better performance than the standard bullet in penetrating RHA and Al2O3/RHA composite armors. The test results, simulation, and theoretical analysis are consistent. This study has practical values for engineering applications to design new ceramic composite bullets. 相似文献
10.
Paulina Piotrkiewicz Justyna Zygmuntowicz Marcin Wachowski Konrad Cymerman Waldemar Kaszuwara Anna Wicaw Midor 《Materials》2022,15(5)
This study’s main goal was to obtain and characterize Al2O3-Cu-Ni composites with different metallic phase content. The study analyzed the three series of samples differing in the metallic phase 5, 10, 15 vol.% volume contents. An identical volume share of the metallic components in the metallic phase was used. Ceramic–metal composites were formed using uniaxial pressing and sintered at a temperature of 1400 °C. The microstructural investigation of the Al2O3-Cu-Ni composite and its properties involved scanning electron microscopes observations and X-ray diffraction. The size of the metallic phase in the ceramic matrix was performed using a stereological analysis. Microhardness analysis with fracture toughness measures was applied to estimate the mechanical properties of the prepared materials. Additionally, magnetic measurements were carried out, and the saturation magnetization was determined on the obtained magnetic hysteresis loops. The prepared samples, regardless of the content of the metallic phase in each series, were characterized by a density exceeding 95% of the theoretical density. The magnetic measurements exhibited that the fabricated composites had ferromagnetic properties due to nickel and nickel-rich phases. The hardness of the samples containing 5, 10, 15 vol.% metallic phases decreased with an increase in the metallic phase content, equal to 17.60 ± 0.96 GPa, 15.40 ± 0.81 GPa, 12.6 ± 0.36 GPa, respectively. 相似文献
11.
Jibin Fan Yimeng Shi Hongxia Liu Shulong Wang Lijun Luan Li Duan Yan Zhang Xing Wei 《Materials》2022,15(5)
Due to the chemically inert surface of MoS2, uniform deposition of ultrathin high-κ dielectric using atomic layer deposition (ALD) is difficult. However, this is crucial for the fabrication of field-effect transistors (FETs). In this work, the atomic layer deposition growth of sub-5 nm La2O3/Al2O3 nanolaminates on MoS2 using different oxidants (H2O and O3) was investigated. To improve the deposition, the effects of ultraviolet ozone treatment on MoS2 surface are also evaluated. It is found that the physical properties and electrical characteristics of La2O3/Al2O3 nanolaminates change greatly for different oxidants and treatment processes. These changes are found to be associated with the residual of metal carbide caused by the insufficient interface reactions. Ultraviolet ozone pretreatment can substantially improve the initial growth of sub-5 nm H2O-based or O3-based La2O3/Al2O3 nanolaminates, resulting in a reduction of residual metal carbide. All results indicate that O3-based La2O3/Al2O3 nanolaminates on MoS2 with ultraviolet ozone treatment yielded good electrical performance with low leakage current and no leakage dot, revealing a straightforward approach for realizing sub-5 nm uniform La2O3/Al2O3 nanolaminates on MoS2. 相似文献
12.
Wipakorn Jevasuwan Yuji Urabe Tatsuro Maeda Noriyuki Miyata Tetsuji Yasuda Hisashi Yamada Masahiko Hata Noriyuki Taoka Mitsuru Takenaka Shinichi Takagi 《Materials》2012,5(3):404-414
Interface-formation processes in atomic layer deposition (ALD) of Al2O3 on InGaAs surfaces were investigated using on-line Auger electron spectroscopy. Al2O3 ALD was carried out by repeating a cycle of Al(CH3)3 (trimethylaluminum, TMA) adsorption and oxidation by H2O. The first two ALD cycles increased the Al KLL signal, whereas they did not increase the O KLL signal. Al2O3 bulk-film growth started from the third cycle. These observations indicated that the Al2O3/InGaAs interface was formed by reduction of the surface oxides with TMA. In order to investigate the effect of surface-oxide reduction on metal-insulator-semiconductor (MIS) properties, capacitors and field-effect transistors (FETs) were fabricated by changing the TMA dosage during the interface formation stage. The frequency dispersion of the capacitance-voltage characteristics was reduced by employing a high TMA dosage. The high TMA dosage, however, induced fixed negative charges at the MIS interface and degraded channel mobility. 相似文献
13.
Jorge Cortez-Elizalde Ignacio Cuauhtmoc-Lpez Zenaida Guerra-Que Alejandra Elvira Espinosa de los Monteros Ma. Antonia Lunagmez-Rocha Adib Abiu Silahua-Pavn Juan Carlos Arvalo-Prez Adrin Cordero-García Adrin Cervantes-Uribe Jos Gilberto Torres-Torres 《Materials》2021,14(19)
NiWAu trimetallic nanoparticles (NPs) on the surface of support Al2O3-CeO2-TiO2 were synthesized by a three-step synthetic method in which Au NPs were incorporated into presynthesized NiW/Al2O3-CeO2-TiO2. The recharge method, also known as the redox method, was used to add 2.5 wt% gold. The Al2O3-CeO2-TiO2 support was made by a sol–gel method with two different compositions, and then two metals were simultaneously loaded (5 wt% nickel and 2.5 wt% tungsten) by two different methods, incipient wet impregnation and ultrasound impregnation method. In this paper, we study the effect of Au addition using the recharge method on NiW nanomaterials supported on mixed oxides on the physicochemical properties of synthesized nanomaterials. The prepared nanomaterials were characterized by scanning electron microscopy, BET specific surface area, X-ray diffraction, diffuse reflectance spectroscopy in the UV–visible range and temperature-programmed desorption of hydrogen. The experimental results showed that after loading of gold, the dispersion was higher (46% and 50%) with the trimetallic nanomaterials synthesized by incipient wet impregnation plus recharge method than with impregnation plus ultrasound recharge method, indicating a greater number of active trimetallic (NiWAu) sites in these materials. Small-sized Au from NiWAu/ACTU1 trimetallic nanostructures was enlarged for NiWAu/ACT1. The strong metal NPs–support interaction shown for the formation of NiAl2O4, Ni-W-O and Ni-Au-O species simultaneously present in the surface of trimetallic nanomaterial probably plays an important role in the degree of dispersion of the gold active phase. 相似文献
14.
Peculiarities of the Phase Formation during Electroconsolidation of Al2O3–SiO2–ZrO2 Powders Mixtures
Zbigniew Krzysiak Edwin Gevorkyan Volodymyr Nerubatskyi Mirosaw Rucki Volodymyr Chyshkala Jacek Caban Tomasz Mazur 《Materials》2022,15(17)
This paper is devoted to the sintering process of Al2O3–SiO2–ZrO2 ceramics. The studied method was electroconsolidation with directly applied electric current. This method provides substantial improvements to the mechanical properties of the sintered samples compared to the traditional sintering in the air. The research covered elemental and phase analysis of the samples, which revealed phase transition of high-alumina solid solutions into mullite and corundum. Zirconia was represented mainly by tetragonal phase, but monoclinic phase was present, too. Electroconsolidation enabled samples to reach a density of 3.0 g/cm3 at 1300 °C, while the sample prepared by traditional sintering method obtained it only at 1700 °C. For the composite Al2O3—20 wt.% SiO2—10 wt.% ZrO2 fabricated by electroconsolidation, it was demonstrated that fracture toughness was higher by 20–30%, and hardness was higher by 15–20% compared to that of samples sintered traditionally. Similarly, the samples fabricated by electroconsolidation exhibited elastic modulus E higher by 15–20%. The hypothesis was proposed that the difference in mechanical and physical properties could be attributed to the peculiarities of phase formation processes during electroconsolidation. 相似文献
15.
Andrs Esteban Cern Corts Anja Dosen Victoria L. Blair Michel B. Johnson Mary Anne White Bojan A. Marinkovic 《Materials》2021,14(14)
Materials from theA2M3O12 family are known for their extensive chemical versatility while preserving the polyhedral-corner-shared orthorhombic crystal system, as well as for their consequent unusual thermal expansion, varying from negative and near-zero to slightly positive. The rarest are near-zero thermal expansion materials, which are of paramount importance in thermal shock resistance applications. Ceramic materials with chemistry Al2−xInxW3O12 (x = 0.2–1.0) were synthesized using a modified reverse-strike co-precipitation method and prepared into solid specimens using traditional ceramic sintering. The resulting materials were characterized by X-ray powder diffraction (ambient and in situ high temperatures), differential scanning calorimetry and dilatometry to delineate thermal expansion, phase transitions and crystal structures. It was found that the x = 0.2 composition had the lowest thermal expansion, 1.88 × 10−6 K−1, which was still higher than the end member Al2W3O12 for the chemical series. Furthermore, the AlInW3O12 was monoclinic phase at room temperature and transformed to the orthorhombic form at ca. 200 °C, in contrast with previous reports. Interestingly, the x = 0.2, x = 0.4 and x = 0.7 materials did not exhibit the expected orthorhombic-to-monoclinic phase transition as observed for the other compositions, and hence did not follow the expected Vegard-like relationship associated with the electronegativity rule. Overall, compositions within the Al2−xInxW3O12 family should not be considered candidates for high thermal shock applications that would require near-zero thermal expansion properties. 相似文献
16.
Haichang Zhang Zhibin Xu Bin Shi Fei Ding Xingjiang Liu Hongzhao Wu Chunsheng Shi Naiqin Zhao 《Materials》2021,14(18)
Cr8O21 can be used as the cathode material in all-solid-state batteries with high energy density due to its high reversible specific capacity and high potential plateau. However, the strong oxidation of Cr8O21 leads to poor compatibility with polymer-based solid electrolytes. Herein, to improve the cycle performance of the battery, Al2O3 atomic layer deposition (ALD) coating is applied on Cr8O21 cathodes to modify the interface between the electrode and the electrolyte. X-ray photoelectron spectroscopy, scanning electron microscope, transmission electron microscope, and Fourier transform infrared spectroscopy, etc., are used to estimate the morphology of the ALD coating and the interface reaction mechanism. The electrochemical properties of the Cr8O21 cathodes are investigated. The results show that the uniform and dense Al2O3 layer not only prevents the polyethylene oxide from oxidization but also enhances the lithium-ion transport. The 12-ALD-cycle-coated electrode with approximately 4 nm Al2O3 layer displays the optimal cycling performance, which delivers a high capacity of 260 mAh g−1 for the 125th cycle at 0.1C with a discharge-specific energy of 630 Wh kg−1. 相似文献
17.
In this study, an Al2O33D/5083 Al composite was fabricated by infiltrating a molten 5083 Al alloy into a three-dimensional alumina reticulated porosity ceramics skeleton preform (Al2O33D) using a pressureless infiltration method. The corrosion resistance of 5083 Al alloy and Al2O33D/5083 Al in NaCl solution were compared via electrochemical impedance spectroscopy (EIS), dynamic polarization potential (PDP), and neutral salt spray (NSS) tests. The microstructure of the two materials were investigated by 3D X-ray microscope and scanning electron microscopy aiming at understanding the corrosion mechanisms. Results show that an Al2O33D/5083 Al composite consists of interpenetrating structure of 3D-continuous matrices of continuous networks 5083 Al alloy and Al2O33D phase. A large area of strong interfaces of 5083 Al and Al2O33D exist in the Al2O33D/5083 Al composite. The corrosion development process can be divided into the initial period, the development period, and the stability period. Al2O33D used as reinforcement in Al2O33D/5083 Al composite improves the corrosion resistance of Al2O33D/5083 Al composite via electrochemistry tests. Thus, the corrosion resistance of Al2O33D/5083 Al is higher than that of 5083 Al alloy. The NSS test results indicate that the corrosion resistance of Al2O33D/5083 Al was lower than that of 5083 Al alloy during the initial period, higher than that of 5083 Al alloy during the development period, and there was no obvious difference in corrosion resistance during the stability period. It is considered that the elements in 5083 Al alloy infiltrated into the Al2O33D/5083 Al composite are segregated, and the uniform distribution of the segregated elements leads to galvanic corrosion during the corrosion initial period. The perfect combination of interfaces of Al2O33D and the 5083 Al alloy matrix promotes excellent corrosion resistance during the stability period. 相似文献
18.
In this paper, the interfacial adhesion work (Wad), tensile strength, and electronic states of the Fe-amorphous Na2SiO3-Al2O3 and Fe-Al2O3 interfaces are well-investigated, utilizing the first-principles calculations. The results indicate that the Fe-amorphous Na2SiO3-Al2O3 interface is more stable and wettable than the interface of Fe-Al2O3. Specifically, the interfacial adhesion work of the Fe-amorphous Na2SiO3 interface is 434.89 J/m2, which is about forty times that of the Fe-Al2O3 interface, implying that the addition of amorphous Na2SiO3 promotes the dispersion of Al2O3 particle-reinforced. As anticipated, the tensile stress of the Fe-amorphous Na2SiO3-Al2O3 interface is about 46.58 GPa over the entire critical strain range, which is significantly greater than the Fe-Al2O3 interface control group. It could be inferred that the wear resistance of Al2O3 particle-reinforced is improved by adding amorphous Na2SiO3. To explain the electronic origin of this excellent performance, the charge density and density of states are investigated and the results indicate that the O atom in amorphous Na2SiO3 has a bonding action with Fe and Al; the amorphous Na2SiO3 acts as a sustained release. This study provides new ideas for particle-reinforced composites. 相似文献
19.
Mateusz Petrus Jarosaw Wo
niak Tomasz Cygan Artur Lachowski Dorota Moszczyska Bogusawa Adamczyk-Cielak Anita Rozmysowska-Wojciechowska Tomasz Wojciechowski Wanda Ziemkowska Agnieszka Jastrzbska Andrzej Olszyna 《Materials》2021,14(13)
This article presents new findings related to the problem of the introduction of MXene phases into the silicon carbide matrix. The addition of MXene phases, as shown by the latest research, can significantly improve the mechanical properties of silicon carbide, including fracture toughness. Low fracture toughness is one of the main disadvantages that significantly limit its use. As a part of the experiment, two series of composites were produced with the addition of 2D-Ti3C2Tx MXene and 2D-Ti3C2Tx surface-modified MXene with the use of the sol-gel method with a mixture of Y2O3/Al2O3 oxides. The composites were obtained with the powder metallurgy technique and sintered with the Spark Plasma Sintering method at 1900 °C. The effect adding MXene phases had on the mechanical properties and microstructure of the produced sinters was investigated. Moreover, the influence of the performed surface modification on changes in the properties of the produced composites was determined. The analysis of the obtained results showed that during sintering, the MXene phases oxidize with the formation of carbon flakes playing the role of reinforcement. The influence of the Y2O3/Al2O3 layer on the structure of carbon flakes and the higher quality of the interface was also demonstrated. This was reflected in the higher mechanical properties of composites with the addition of modified Ti3C2Tx. Composites with 1 wt.% addition of Ti3C2Tx M are characterized with a fracture toughness of 5 MPa × m0.5, which is over 50% higher than in the case of the reference sample and over 15% higher than for the composite with 2.5 wt.% addition of Ti3C2Tx, which showed the highest fracture toughness in this series. 相似文献
20.
Combustion synthesis involving metallothermic reduction of MoO3 by dual reductants, Mg and Al, to enhance the reaction exothermicity was applied for the in situ production of Mo3Si–, Mo5Si3− and MoSi2–MgAl2O4 composites with a broad compositional range. Reduction of MoO3 by Mg and Al is highly exothermic and produces MgO and Al2O3 as precursors of MgAl2O4. Molybdenum silicides are synthesized from the reactions of Si with both reduced and elemental Mo. Experimental evidence indicated that the reaction proceeded as self-propagating high-temperature synthesis (SHS) and the increase in silicide content weakened the exothermicity of the overall reaction, and therefore, lowered combustion front temperature and velocity. The XRD analysis indicated that Mo3Si–, Mo5Si3– and MoSi2–MgAl2O4 composites were well produced with only trivial amounts of secondary silicides. Based on SEM and EDS examinations, the morphology of synthesized composites exhibited dense and connecting MgAl2O4 crystals and micro-sized silicide particles, which were distributed over or embedded in the large MgAl2O4 crystals. 相似文献