Journal of Central South University
·
2021
·Vol. 28
·期 4
·1233-1243
·
IF 1.716
Rao Wei-dong,Liu Yao,Cheng Li-jing,Liu Shao-jun
Combining sintering additive with field assisted sintering, stereolithographical dense Si 3 N 4 ceramics was successfully fabricated. Owing to a large amount of polymer during the stereolithography, the green parts have the characteristics of low powder loading and high porosity. Adjusting the process parameters such as sintering temperature and soaking time can effectively improve the density of the specimens. The stress exponent n of all specimens is in a range of 1 and 2, which is derived from a modified sintering kinetics model. The apparent activation energy Q d of stereolithographic Si 3 N 4 ceramics sintered with applied pressures of 30 MPa, 40 MPa, and 50 MPa is 384.75, 276.61 and 193.95 kJ/mol, respectively, suggesting that the densification dynamic process is strengthened by raising applied pressure. The grain boundary slipping plays a dominating role in the densification of stereolithographic Si 3 N 4 ceramics. The Vickers hardness and fracture toughness of stereolithographic Si 3 N 4 ceramics are HV10/10 (1347.9±2.4) and (6.57±0.07) MPa·m 1/2 , respectively.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE & TECHNOLOGY
·
2025
·
IF 14.3
Xuyang Shang,Yuxin Lin,Keke Hou,Yajuan Zhong,Changqing Cao,Yanhui Wang,Hongtao Zeng,Jun Lin
Yttrium hydride (YH x ) is a highly promising neutron moderator material for nuclear reactors, known for its exceptional thermal stability and high hydrogen content. This study investigated the sintering mechanism and microstructural evolution of YH x monoliths processed by spark plasma sintering (SPS), with the effects of temperature, duration, and pressure. The results indicate that the sintering process can be divided into five stages: formation of sintering necks, rapid densification, anti-densification, recrystallization, and grain growth. The anti-densification behavior is attributed to hydrogen desorption, phase transformation-induced volumetric contraction, and vacancy coalescence from hydrogen migration, leaving residual pores and lattice defects. Furthermore, increasing the sintering temperature and duration promotes recrystallization and grain growth, whereas elevated pressure effectively suppresses grain boundary migration. This research establishes fundamental processing-structure correlations critical for optimizing YH x moderators in nuclear applications.
研究领域:
材料科学
·
核能工程
✓ 已验证
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2022
·
IF 4.804
Lei Huang,Yafei Pan,Jiuxing Zhang,Yong Du,Yuhui Zhang
W-30Si refractory targets were widely used as gate materials in the field of semiconductor integrated circuits. This work aimed to study the microstructure, densification mechanism, and mechanical properties of W-30Si targets prepared by spark plasma sintering (SPS). The results manifested that the punch displacement and relative density rose as temperatures increased, and the sintering route processed at 1200 °C included four parts. A fully dense target can be obtained at 1200 °C, while part of Si would volatilize at 1220 °C. No significant variation was observed in grain sizes from 1000 to 1200 °C, thus it was believed that the consolidation predominated over this temperature range. The effective stress exponent ( n ) was generally regarded as a parameter closely related to the densification mechanism. At the initial stage of 1000 to 1200 °C and the late stage of 1000 °C ( n < 1), the particle rearrangement had a major influence on the densification. At the late stage of 1050 to 1200 °C (1 < n < 2), the grain boundary diffusion was a significant factor for consolidation, and the activation energy ( n = 1.5) was estimated to be 931.40 kJ/mol. Besides, the microhardness rose with increasing temperatures. The present study laid the groundwork for future research on the fabrication of W-30Si targets by SPS.
研究领域:
材料科学
·
机械工程
✓ 已验证
DOI
高影响因子
Materials Research Express
·
2024
·Vol. 11
·期 7
·075101
·
IF 1.8
Lina Zhan,Yao Zhang,Xuan Zhang,Yuzhibiao Xia,Yao Liu
The densification mechanism of CeO2 doped Si3N4 ceramics during spark plasma sintering (SPS) was investigated. The sintering process was observed to undergo significant densification at the intermediate stage of sintering (1435 °C–1816 °C), and the density and grain size of CeO2 doped Si3N4 ceramic were found to be greater than those of pure Si3N4 ceramic under the same sintering conditions. To determine the densification mechanism, a creep model was utilized to determine the densification mechanism which could be interpreted based on the values of the stress exponent (n) and the apparent activation energy (Qd). The results revealed that the Qd of pure Si3N4 (381.15 kJ mol−1) is higher than that of Si3N4-CeO2 powder (265.61 kJ mol−1). Moreover, the stress exponent n of Si3N4-CeO2 powder (1.12–1.33) was higher than that of pure Si3N4 powder (1.00–1.18). This can be attributed to the fact that the addition of CeO2 resulted in the formation of a liquid phase at the grain boundary which leading to a shift in the controlling mechanism from grain boundary diffusion to grain boundary sliding.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
ADVANCED POWDER TECHNOLOGY
·
2019
·
IF 3.25
Ruifeng Liu,Wenxian Wang,Hongsheng Chen,Zhen Lu,Wei Zhao,Tingting Zhang
In this study, high-quantity pure magnesium was prepared by SPS, and the sintering densification mechanism was discussed by using numerical simulation and simultaneous experiment. Results show that a layer of dense magnesium oxide was formed at the surface of Mg particles, and the oxide reduction can be observed owing to the effect of oxide film removal in SPS. The high energy pulsed current flows preferentially through particle contact surfaces, which provides the conditions for the generation of micro-arc between particles and the temperature at the particles contact point can be up to 1979 °C. With the low pressure at the initial sintering stage, local high temperature induced by micro-arc makes the melting (even evaporation) appearance. At the same sintering temperature of 570 °C, the obvious difference in bending strength also demonstrates the significance of spark discharge in SPS. The formation process of sintering neck demonstrates that sintering process is the reflection of melting (even evaporation), diffusion and plastic deformation. In order to realize tiny area and high-quality connection between powder particles, an innovative powder sintering technology using high-frequency pulse electric current (High frequency pulse current assisted sintering) is proposed based on the enlightenment of the skin, proximity and arc discharge effect of high-frequency pulse current. This technology is also instructive for other alloys and engineering materials.
研究领域:
材料科学
·
冶金工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Haomin Wang,Yang Shi,Mao Deng,Zhangyi Huang
High-pressure sintering (HPS) is a promising technique for producing nanocrystalline ceramics with unique properties. However, the densification mechanisms of HPS for nanocrystalline ceramics at different sintering stages remain controversial. This study focuses on Gd 2 Zr 2 O 7 (GZO) nanocrystalline ceramics, investigating their microstructure evolution and densification behavior under varying pressures, temperatures, and dwelling times. The HPS process involves distinct stages: cold compaction, hot compaction, and isothermal progression. During cold compaction, densification is driven by the breakdown of aggregates, particle rearrangement, and local plastic deformation , resulting in a relative density of 84.8 %. The intermediate stage achieves an increase to ∼93.7 % in relative density by grain boundary-mediated plastic deformation mechanism . The final isothermal stage, held at 500 °C/5 GPa, achieves nearly full density (∼99.2 %) through diffusion creep , eliminating microstructural defects. This comprehensive understanding of HPS densification mechanisms, exemplified by GZO ceramics, contributes to advancing nanocrystalline ceramic applications .
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
Journal of the Australian Ceramic Society
·
2023
·Vol. 59
·期 5
·1231-1239
·
IF 1.9
Zhang Mengwen,Jiang Binyang,Yang Lutong,Cao Na,Li Zhaosheng,Fan Lei,Yang Shoulei
The emerging oscillatory pressure sintering technology is used to prepare high-performance Al 2 O 3 -Ti(C,N) ceramic tools for high-speed cutting. By recording the displacement during sintering, the sintering shrinkage rate of the Al 2 O 3 -Ti(C,N) composite was calculated, and the stress exponent n and sintering activation energy Q were calculated according to creep theory to determine the densification mechanism. In addition, the evolution of phases, microstructure and hardness of the composite was also observed. Results show that during oscillatory pressure sintering process at 1400 °C and 1300 °C, the stress exponent of Al 2 O 3 -Ti(C,N) composite is around 2.2 and the sintering activation energy is 486 kJ mol −1 , indicating that the densification mechanism is a diffusion-controlled grain boundary sliding of Al 2 O 3 phase. Additionally, as the oscillatory pressure increases, the average grain size of the Al 2 O 3 decreases and the Vickers hardness increases. Hardness achieves the highest 22.7 GPa when the median oscillatory pressure is 70 MPa at 1400 °C, which is 1 GPa higher than that of static pressure of 70 MPa.
研究领域:
材料科学
·
机械工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF THE EUROPEAN CERAMIC SOCIETY
·
2022
·
IF 6.364
Mao chen,Fan Zhang,Hailong Wang,Gang Shao,Bingbing Fan,Rui Zhang,Hongxia Li,Yongqiang Chen
The dense h-BN/ZrO 2 (30 wt%) composites without additives were rapidly fabricated by spark plasma sintering . The relative density, apparent porosity, fracture toughness, flexural strength , phase composition and microstructure of h-BN/ZrO 2 composites were systematically investigated. Besides, the corrosion resistance of h-BN/ZrO 2 composites in molten steel was also studied in detail. Especially, the h-BN/ZrO 2 composites were sintered at 1800 °C exhibiting a relative density of 96.6% and the flexural strength of ≈ 157 MPa. The corrosion of h-BN/ZrO 2 composites was mainly due to the oxidative decomposition of BN, and the corrosion process was clarified by a parabolic law. The excellent corrosion resistance of the h-BN/ZrO 2 composites was attributed to ZrO 2 residual layer formed at the interface. The corrosion thickness of h-BN/ZrO 2 composites was only ∼116 µm even using the longest corrosion time (80 min). The composites could be a promising candidate material applied to fabricated thin strip continuous casting side sealing plates.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Zhangyi Huang,Jiaochun Zheng,Mingyu Su,Mao Deng,Yang Shi,Ruichong Chen,Qingyuan Wang,Zhijun Wang,Jianqi Qi,Rui Li,Haomin Wang
Densifying transition metal carbide (TMC) ceramics is challenging due to their low diffusion coefficient and strong covalent bonding. Ultra-high-pressure sintering (UHPS) is a promising technique for preparing dense ceramic materials at low temperatures, but it is underutilized in TMC ceramics. Herein, we report the successful employment of UHPS at 1500 °C for 3 min with an auxiliary pressure of 7 GPa, yielding TaC, NbC, TiC, and ZrC ceramics with relative densities of 99.3%, 98.9%, 98.2%, and 96.4%, respectively. We demonstrate that the densification mechanism of the TMC ceramic in this investigation encompasses plastic deformation and high-pressure assisted atomic diffusion. Furthermore, we determine the Vickers hardness and fracture toughness of TaC, NbC, TiC, and ZrC ceramics to be 16.5, 15.9, 24.0, and 17.7 GPa and 2.5, 2.9, 2.8, and 1.8 MPa m 1/2 , respectively. Moreover, with increasing temperature from room temperature to 500 °C, the hardness and elastic modulus of all four TMC ceramics gradually decrease, with the hardness declining by approximately 17–25%.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
产品关联
DOI
高影响因子
INTERNATIONAL JOURNAL OF REFRACTORY METALS & HARD MATERIALS
·
2023
·
IF 3.6
Chuanbin Wang,Yongxin Cheng,Sumeng Hu,Kejia Kang,Yuzhe Han,Xudan Zhang,Xiangping Dai,Guoqiang Luo
Tungsten (W)-based composites with 1 wt% SiC were consolidated via field assisted sintering (FAST). FAST was conducted at temperatures ranging from 1000 °C to 1700 °C with holding times of 1–10 min under a pressure of 50 MPa. The densification and grain growth mechanisms were investigated using a creep deformation model and the grain growth power law. Various densification and grain growth mechanisms corresponded to different effective stress exponents ( n ) and grain growth exponents ( p ). n is the stress exponent associated with the densification mechanism, and p is the grain growth exponent related to the grain growth mechanism. The densification process mainly occurred at 1000 °C–1400 °C, whereas grain growth mainly occurred at 1500 °C–1700 °C. The W-Si-C composites were densified primarily through particle rearrangement (when n is ∼1), intergranular diffusion (when n is ∼2), and the dislocation-climb mechanism (when n is 3.62). The activation energies were estimated to be 153.80 and 541.17 kJ/mol at the effective stress exponents ( n ) of 1 and 2, respectively. Furthermore, intergranular diffusion is speculated to cause grain growth. The sintering temperature considerably affected the microstructure of W-Si-C composites. The silicide formed at sintering temperatures of <1100 °C was WSi 2 , and it transformed into W 5 Si 3 with increasing sintering temperature.
研究领域:
材料科学
·
工程学
✓ 已验证
产品关联
DOI
高影响因子
SCRIPTA MATERIALIA
·
2019
·
IF 4.539
Nan Lu,Gang He,Zengchao Yang,Yong Li,Jiangtao Li
MgO/Graphene composites were prepared by combustion synthesis (CS) followed with spark plasma sintering (SPS) using LiF as sintering additive. The densification mechanism of MgO/Graphene composites doped with LiF was systematically investigated. With incorporating small amount of graphene into MgO , the spectral absorptivity of the composite was improved, whereas the density, hardness and average grain size were decreased. The densification of submicron sized MgO/Graphene ceramics was realized by the balance between sintering promoted by LiF and grain refinement of graphene.
研究领域:
材料科学
·
陶瓷工程
✓ 已验证
DOI
高影响因子
Journal of the Mechanical Behavior of Biomedical Materials
·
2023
·
IF 3.9
Mengxing Ge,Deqiao Xie,Youwen Yang,Zongjun Tian
Over the past few years, biodegradable ceramic scaffolds have gained significant attention in the field of bone repair. Calcium phosphate (Ca 3 (PO 4 ) 2 )- and magnesium oxide (MgO)-based ceramics are biocompatible, osteogenic, and biodegradable, making them attractive for potential applications. However, the mechanical properties of Ca 3 (PO 4 ) 2 are limited. We developed a magnesium oxide/calcium phosphate composite bio-ceramic scaffold characterized by a high melting point difference, using vat photopolymerization (VP) technology to address this issue. The primary goal was to fabricate high-strength ceramic scaffolds using biodegradable materials . In this study, we investigated ceramic scaffolds with varying MgO contents and sintering temperatures . We also discussed the co-sintering densification mechanism of high and low melting-point materials associated with composite ceramic scaffolds. During sintering, a liquid phase was generated, which filled up the pores generated during the vaporization of additives (such as resin) under the influence of capillary force . This led to an increase in the extent of ceramic densification realized. Moreover, we found ceramic scaffolds with 80 wt% MgO exhibited the best mechanical performance. This kind of composite scaffold performed better than pure MgO scaffold. The results reported herein highlight that high-density composite ceramic scaffolds can be potentially used in the field of bone repair.
研究领域:
生物材料学
·
骨修复领域
✓ 已验证
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）