Journal of Materials Research and Technology-JMR&T
·
2022
·
IF 6.267
Xu Liu,Shizhen Li,Jiajie Fan,Jing Jiang,Yang Liu,Huaiyu Ye,Guoqi Zhang
Robust bonding of Cu quasi-nanoparticles sintering for Ag coated chip and bare copper substrate was achieved. The effect of temperature, pressure and time on the sintering bonding strength and microstructural evolution was deeply studied. 36.5 MPa shear strength was achieved when applied 5 MPa pressure. By increasing to 30 MPa, it shows the best die shear strength of 116 MPa, accomplished with a sintering temperature of 250 °C for 3 min. Temperature also influenced the shear strength a lot. Between 210 °C and 230 °C can already provide strength over 30 MPa. When increased to 270 °C, the strength was extremely enhanced to over 120 MPa. Inspection on the fracture behaviors and cross-section of sheared off samples was conducted by SEM, EDS, and XRD. It is found that low bonding performance is due to both of the incomplete burnt out of organics and incomplete Cu QNPs sintering. In addition, high bonding is account for the positive effect of pressure and temperature on promoting the necking growth, sintering networking formation, pores isolation and brittle-ductile fracture transformation. The recommended sintering profile is 250 °C, 3 min, 20 MPa. Finally, the feasibility for SiC MOSFET power electronics DA was verified by testing its static characteristics at both room temperature and 150 °C.
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高影响因子
CERAMICS INTERNATIONAL
·
2021
·
IF 4.527
Chen Zeng,Mingyu Zhang,Hanwei He,Xiaodong Wang,Kai Tong,Yafeng Wang,Ping Xu,Lei Zheng,Guang Zeng,Zhean Su,Qizhong Huang
Sol-gel is a promising technology to prepare the C/C–ZrC–SiC composites. However, carbon fiber erosion caused by carbothermal reduction severely degrades properties of the composites. At present study, the addition order of carbon source during sol-gel process was optimized to improve the microstructure, mechanical property and ablation resistance of the composites. Results show that adding phenolic resin before gelation combined with deposited pyrocarbon interlayer around the carbon fibers can greatly alleviate the degradation of the C/C–ZrC–SiC composites by reducing the carbon fiber erosion. The composites thus prepared delivered the flexural strength , mass and linear ablation rates are 162.58 MPa, 0.147 mg/(cm 2 ⋅s) and 0.0098 mm/s, respectively, which are 449% higher, 9.26% lower and 38.36% lower than those of the counterpart that added phenolic resin after gelation. The excellent performance is attributed to little erosion of the carbon fibers and the dense matrix of ZrC–SiC ceramics obtained from adding carbon source before gelation during the sol-gel process.
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高影响因子
JOURNAL OF MATERIALS PROCESSING TECHNOLOGY
·
2021
·
IF 5.551
Wantang Wang,Baoguo Zhang,Yunhui Shi,Tengda Ma,Jiakai Zhou,Ru Wang,Hanxiao Wang,Nengyuan Zeng
Chemical mechanical polishing (CMP) has revolutionized the processing of semiconductor material such as silicon carbide (SiC). However, the strong chemical bond between silicon atoms and carbon atoms gives SiC materials a very high mechanical hardness and chemical stability. Therefore, SiC wafers may suffer from a low material removal rate (MRR) and serious subsurface damage when traditional CMP methods are used. In this study, to improve the CMP properties of Si-face of the 4H-SiC wafers, the synergistic effect of UV and TiO 2 on the activation of persulfate (PS) was investigated for the first time. The response surface method was employed to study the effect of pH, PS concentration, and TiO 2 dosage on CMP in-depth, and to ultimately optimize the polishing process. The analysis demonstrated that an MRR of 608 nm/h can be obtained with the average surface roughness ( Sq ) of 0.521 nm when the pH is 6, in which the TiO 2 dosage is 0.015 wt% and the PS concentration is 3 wt%. Polarization curves , AC impedance spectra and X-ray photoelectron spectroscopy tests were performed to further analyze the chemical action of the slurry, which showed that the introduction of UV-TiO 2 strongly enhances the chemical action of slurry and results in the formation of a passivated layer on the SiC surface. Finally, based on the radical quenching experiments and the results mentioned above, a model that relates to the removal of 4H-SiC by UV-TiO 2 synergistic activation of PS is proposed.
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高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2021
·
IF 5.302
Wei Xie,Qiangang Fu,Chunyu Cheng,Pei Zhang,Ningning Yan
The medium-entropy oxide (Y 1/3 Yb 1/3 Lu 1/3 ) 2 O 3 with a body-centered cubic structure was successfully synthesized by solid-state reaction process, and then it was introduced into SiC ceramic to study its effect on the oxidation behavior of SiC ceramic at 1700 °C. The (Y 1/3 Yb 1/3 Lu 1/3 ) 2 O 3 -modified SiC ceramic exhibited better oxidation resistance than its individual oxides (Y 2 O 3 , Yb 2 O 3 , and Lu 2 O 3 ) modified SiC ceramic. The experimental and calculated results all indicate that the rare-earth atoms had the tendency to diffuse into the SiO 2 structure and occupy the interstitial positions within SiO 2 structure. The introduction of medium-entropy oxide (Y 1/3 Yb 1/3 Lu 1/3 ) 2 O 3 reduced the initial oxidation rate of the ceramic samples (1−3 h), and enhanced the stability of SiO 2 structure, thus resulting in a better oxidation resistance at 1700 °C.
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高影响因子
APPLIED SURFACE SCIENCE
·
2021
·
IF 6.707
Dongyang Zhang,Hongying Yu,Anzhe Wang,Qi Wang,Lu Ren,Ping Hu,Dongbai Sun
The need for synergy of strengthening and anti-oxidation under high-temperature and oxidative environment imposes new demands on nonablative thermal protection materials. Herein, 2D C f /ZrB 2 -SiC composite with superior damage tolerance and excellent oxidation resistance were constructed using a simple fiber heat treatment. An enhanced flexural strength of 234 ± 18 MPa and an intermediate work of fracture of 1342 J/m 2 were obtained for 2D C f-HT /ZrB 2 -SiC composite, increasing by nearly 19.4% and 171.7% as compared with those of C f-AR /ZrB 2 -SiC sample, triggered by multiple toughening mechanisms including crack bifurcation, fiber bundles pull-out and bridging. The surface of 2D C f-HT /ZrB 2 -SiC composite was covered with a dense silica glass layer and embedded with a few zirconia particles after oxidation at 1500 °C for 1 h, resulting in an excellent oxidation resistance. This work presents a simple approach to achieve the synergy of superior damage tolerance and oxidation resistance of continuous carbon fiber reinforced ceramic matrix composite.
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高影响因子
Journal of Advanced Ceramics
·
2020
·Vol. 9
·期 3
·320-328
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IF 2.889
Yu Zhaoju,Yang Yujing,Mao Kangwei,Feng Yao,Wen Qingbo,Riedel Ralf
A novel single-source-precursor for SiC-TaC-C nanocomposites was successfully synthesized by the chemical reaction between a polycarbosilane (allylhydridopolycarbosilane, AHPCS) and tantalum(V) chloride (TaCl 5 ), which was confirmed by Fourier transform infrared spectra (FTIR) measurement. After pyrolysis of the resultant single-source-precursors at 900 °C, amorphous ceramic powders were obtained. The 900 °C ceramics were annealed at different temperatures in the range of 1200–1600 °C to gain SiC-TaC-C nanocomposites. The phase evolution of ceramic nanocomposites was investigated by X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results indicate that the TaC starts to crystallize at lower temperature than the β-SiC. It is particularly worth pointing out that the unique core-shell structured TaC@C nanoparticles were in-situ formed and homogeneously distributed in the ceramic matrix after annealing at 1400 °C. Even at a high temperature of 1600 °C, the grain sizes of β-SiC and TaC are smaller than 30 nm, fulfilling the definition of nanocomposites. The present study related to SiC-TaC-C nanocomposites paves a new road for enriching ultra-high temperature ceramic family suitable for structural/functional applications in harsh environment.
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高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2019
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IF 3.131
Chuanbo Hu,Ying Li,Tingzhen Li,Yongquan Qing,Jianting Tang,Huawei Yin,Lei Hu,Lei Zhang,Yongsheng Xie,Kangning Ren
In this investigation, a comparative study on the anticorrosion properties of poly( N -methylaniline) (PNMA) coating, as well as PNMA-ZnO and PNMA/SiC-ZnO bilayer coatings, was carried out. The polymeric materials (PNMA and PNMA/SiC composite) were synthesized by emulsion polymerization method. The structures of the obtained polymeric materials were determined by different optic techniques, and the electrochemical activity and stability were examined by cyclic voltammetry . Subsequently, PNMA was spread on the surfaces of carbon steel and ZnO coating by chemical deposition method, and PNMA/SiC was spread on the surface of ZnO coating, which led to obtaining PNMA coating, PNMA-ZnO and PNMA/SiC-ZnO bilayer coatings. The structures of ZnO coating were characterized by X-ray diffraction and energy dispersive spectrometer, and the surface morphologies of all the coatings were also studied by field emission scanning electron microscopy . The anticorrosion properties of all the coatings were evaluated by electrochemical corrosion and accelerated immersion in the presence of a 3.5% NaCl solution. The results demonstrated that the polymeric materials-ZnO bilayer coatings had excellent corrosion protection ability, and in specific, for the carbon steel protected by PNMA/SiC-ZnO bilayer coatings it was higher than PNMA-ZnO bilayer coatings, with a corrosion rate of 0.004 mm/year and the protection efficiency was up to 97.43%. Overall, this study proves that the rough ZnO coating is beneficial to the embedding and pinning of polymeric materials, and the formed PNMA/SiC-ZnO bilayer coatings possess a strong adsorption ability and wide coverage area to the carbon steel substrate, which facilitates the external PNMA/SiC film to develop its unique barrier and passivation effects to prevent carbon steel from being corroded. The protection mechanism conferred by polymeric materials-ZnO bilayer coatings has also been discussed.
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高影响因子
Journal of Materials Research and Technology-JMR&T
·
2022
·
IF 6.267
Wei Zhao,Rui-feng Liu,Jie Yan,Xian Wang,Hong-wei Zhang,Wen-xian Wang
The microstructure evolution and mechanical properties of 5 wt% SiC/7075Al composites processed with a combination of three-step spark plasma sintering (SPS), hot rolling (HR), and high-frequency electric pulse assisted treatment (HEAT) processing were investigated herein. It was found that the HEAT tremendously promoted the recrystallization behavior after the hot rolling, leading to grain refinement and residual stress weakening. It can be attributed to the combination of the electrical (Electron wind) and thermal effects (Joule heat) of pulse current. Electron wind promotes the expansion of the movement of dislocations, providing the material basis for recrystallization. Joule heat and residual stress within the matrix provide the substance conditions. There was a remarkable improvement in strength and ductility, among which the increase in strength was mainly due to the combined effect of phase precipitation strengthening and grain refinement, while the increase in elongation was mainly attributed to grain refinement and residual stress weakening. Compared to those of the untreated samples, the average grain size decreased by 18.3%, residual stresses reduced by 70%, and tensile strength improved by 37.3%. High-frequency assisted treatment has a comprehensive improvement on the microstructure and mechanical properties of SiC/7075Al composites.
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高影响因子
CERAMICS INTERNATIONAL
·
2022
·
IF 5.532
Ying Mu,Liwen Yan,Peisen Liu,Qichao Gao,Anran Guo,Xiaojing Xu,Haiyan Du,Shun Dong,Jiachen Liu
As a critical structure of thermal protection systems, flexible fibre insulation felts are widely used on the leeward surface of spacecrafts. To enhance the thermal resistance of flexible fibre felts, SiC w -ZrO 2 coatings with different SiC whisker (SiC w ) contents were fabricated on the surface of a high-silica-fibre fabric (HSFF) by employing a sol-gel method combined with a spraying route. The introduction of SiC w having a length of 10–50 μm effectively improved the coating integrity. After calcination at 1000 °C for 1 h, the SiC w -ZrO 2 coating containing 8 wt% SiC w did not damage the tensile strength and flexibility of the fibre fabric, and the interfacial bonding strength between the coating and HSFF reached 0.40 MPa, benefitting from the whisker toughening mechanism. The SiC w -ZrO 2 coating with a high emissivity of 0.96 in the 2–14 μm wavelength range reduced the surface temperature of the flexible insulation felt by approximately 300 °C when a butane torch was applied at above 1300 °C.
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高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Lei Zheng,Zhanjun Liu,Hongchao Zhao,Quangui Guo,Mingyu Zhang,Qizhong Huang
In this work, high-sinterability ZrC–SiC–TiC ceramic powders were synthesised through a sol-gel approach coupled with subsequent carbothermal reactions. Specifically, MgCl 2 was utilised as an additive to enhance the sintering activity of the powders. Experimental results revealed that the introduction of Mg and variation in Zr/Ti molar ratios significantly influenced the phase and morphological evolution of the precursor. In the form of a Mg–Si–O liquid phase, Mg promoted carbothermal reduction and solid-solution reactions. It ultimately remained as amorphous Mg–Si–O oxide in the final ZrC–SiC–TiC ceramic powders, effectively improving the sintering activity of ceramic powders. Consequently, dense Mg-modified ZrC–SiC–TiC ceramics with high relative density up to 99.2 % were successfully fabricated by spark plasma sintering at 1700 °C and 30 MPa.
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高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Yeqi Zhu,Chao Jin,Zhonghao Ning,Wenyan Huang,Shengjian Mao,Zhichao Xue,Siqi Lan,Qianwen Tao,Rongqian Yao
Actualization of well-balanced high porosity with simultaneous increase in hardness/fracture toughness for thermal insulation composites in hypersonic aerospace vehicle components is always of great challenge. Considering significant toughening effect of unique Mo 4.8 Si 3 C 0.6 -SiC composites microstructure, an agile strategy is proposed to prepare porous Mo 4.8 Si 3 C 0.6 /SiC(rGO) polymer-derived ceramics (PDCs) via re-pyrolysis of ball-milling-induced MoSi 2 -SiC(rGO) p /polycarbosilane-vinyltriethoxysilane-graphene oxide (PVG) precursors blends with polystyrene (PS) as pore-forming agent. In-situ formed Mo 4.8 Si 3 C 0.6 -β-SiC nanocrystals , possessing eminent mechanical properties and good compatibility with SiO x C y /C free , can significantly strengthen interface bonding and increase disorder of ceramic network. Such effective hindrance to crack propagation moderates the inherent brittleness while retaining high hardness of SiC PDCs. Moreover, dense Mo 4.8 Si 3 C 0.6 -β-SiC/SiO x C y /C free (rGO) framework, with spontaneous regular pore structure , well balances loading/thermal insulation capacity. Particularly, samples with 10 wt.% PS exhibit outstanding mechanical performances (hardness: 5.10 GPa; fracture toughness: 2.24 MPa·m 1/2 ; compressive strength : 58.15 MPa) and low thermal conductivity (0.8427 W·m - 1 ·K - 1 ). As demonstrated, products remain decent structural integrity after ablation of butane blowtorch flame for 1-20 min. The synergy oxidation with fast response of Mo 4.8 Si 3 C 0.6 and durability of β-SiC facilitates great anti-oxidation ability, opening up manufacture of SiC-based composites for thermal protection system (TPS) of hypersonic vehicles and re-entry spacecraft with ultra-high speed.
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高影响因子
POLYMER
·
2023
·
IF 4.6
Weiyi Ding,Liwei Yan,Mingyan Huang,Yinfu Luo,Yang Chen,Mei Liang,Huawei Zou,Zhengguang Heng
To meet the urgent need for thermal protection of high-temperature deformable mechanisms in the aerospace industry, a novel strategy for the preparation of ablation-resistant flexible composites is proposed. Ceramic precursor is selected and introduced to epoxy modified silicone rubber (SR) to in-situ build SiC frame at high temperature to fabricate flexible thermal protective polymeric materials with excellent ablation resistance. The static ablation and dynamic ablation behaviors of the SR composites are systematically and comparatively investigated in a tube furnace and oxyacetylene torch in an automatic ablation machine for the first time. The influence of polycarbonylsilane (PCS) content on the microstructure, strength and composition of char layer, and the ablation properties at different heat environments are discussed. When the addition of PCS reached 10 phr, for the static ablation, the maximum puncture strength of char and the residual weight increased 3233% and 48.48%, respectively. The same for dynamic ablation, with the introduction of PCS, each indicator was greatly improved. Moreover, the ablation enhancement mechanisms of PCS in different ablation environments are revealed. This work may provide a new perspective for the preparation of silicone rubber composites with excellent ablation performance, expected to be well used as a thermal protection coating for hypersonic spacecrafts.
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高影响因子
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