CERAMICS INTERNATIONAL
·
2023
·
IF 5.2
Hantao Li,Xuewei Luo,Shuo Huang,Kaiyun Li,Sheng Zhang,Hongyun Jin
Single-phase high entropy ceramic (Ca 0.5 Sr 0.5 )(5RE) 2 O 4 (RE = Y, Sm, Gd, Dy, Yb) (CSHO) with anti-spinel structure was synthesized via solid-state reaction method. The CSHO has good high-temperature phase stability at 1600 °C for 10–50 h. In addition, the CSHO ceramics exhibit much lower thermal conductivity and higher thermal expansion coefficient than that of SrY 2 O 4 , towing to the intensified phonon-point defect scattering and the enhanced anharmonic vibrations of the lattice. The thermal conductivity of CSHO is 1.48–1.81 W∙m −1 K −1 (25–1500 °C), and the thermal expansion coefficient is 11.5–12.0 × 10 −6 K −1 (1000–1500 °C). The obtained results suggest that CSHO has the potential to become the next-generation thermal barrier coating materials.
研究领域:
材料科学
·
热物理
✓ 已验证
产品关联
DOI
高影响因子
POLYMER
·
2023
·
IF 4.6
Lidong Cao,Yaqing Wen,Xingzhong Fang,Guofei Chen
With the applications of injection molding optical components, higher requirements are put forward for thermoplastic polyimides (TPIs) in terms of transparency and coefficient of thermal expansion (CTE). Two series of thermoplastic polyamide-imides (PAIs) derived from 2,2'-(2,2′-bis(trifluoromethyl)-[1,1′-biphenyl]-4,4′-diyl)bis(1,3-dioxoisoindoline-5-carbonyl chloride) (CT-TFDB) and rigid/flexible aromatic diamines with specific groups were prepared at room temperature , which both exhibited moderate glass transition temperatures ( T g s) in the range of 251–274 °C, excellent dimensional stability with CTE values of 17–34 ppm/K, high transmittance ( T 450nm ≥ 59%) and good thermoplasticity with - d log E' / dT values of 0.08–0.34. Among them, PAI-2a exhibited the best comprehensive performances, especially for the high thermoplasticity (- d log E' / dT = 0.34), low CTE (28 ppm/K), and high transmittance ( T 450nm = 84%), which provides a new strategy for the research on thermoplastic PAI materials in optical field.
研究领域:
材料科学
·
光学工程
✓ 已验证
产品关联
DOI
高影响因子
Case Studies in Construction Materials
·
2024
·
IF 6.5
Ang Su,Yujiang Wang,Rui Wang,Yang Chu,Wen Xu,Qian Tian,Sen Yao,Qingyu Meng,Wenbin Wang
Internal curing is an effective method to reduce the autogenous shrinkage of cementitious materials. Besides, the increasing in relative humidity (RH) due to the internal curing also reduces the coefficient of thermal expansion (CTE), which is beneficial for enhancing the anti-cracking performance of cementitious materials. In this paper, effects of superabsorbent polymers (SAP) on the microstructure and performance of cementitious materials were investigated. The superabsorbent polymer (SAP) changes the time and spatial distribution of water in cementitious materials, so it should have an influence on the microstructure of cement matrix, thus affecting the performance of cementitious materials. Results indicate that the CTE of concrete increases over time, while that of concrete with SAP shows a completely different behavior. In 0.1 % SAP system, the CTE increases slowly over time after about 2days, while in 0.2 % SAP and 0.3 % SAP systems, the CTE is nearly stabilized during the test period. Low-field nuclear magnetic resonance (LF NMR) results indicate that the SAP decreases the number of empty capillary pores and increases the total porosity, which inhibits the increase of CTE over time. The dosage of SAP plays an important role in enhancing the internal curing performance. By increasing the dosage of SAP, the number of empty capillary pores decreases, the saturation degree of capillary pores rises, and consequently, the CTE and autogenous shrinkage of concrete are reduced.
研究领域:
土木工程
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
·
2024
·
IF 8.3
Qiangsheng Sun,Yudi Feng,Ke Jin,Jia Guo,Changchun Wang
The coefficient of thermal expansion (CTE) of adhesives is considered to be a vital parameter for dental restoration due to the oral temperature fluctuation induced by hot and cold drinks in daily life. Even more challenging, the adhesives need to bond various materials with different CTE values, and mismatched thermal expansion at the interface of two materials will produce thermal stress and cause cracking, leading to bond failure. In this study, we designed and synthesized a divinyl monomer containing a dibenzocyclooctadiene (DBCOD) unit, which was incorporated into a commercial adhesive, Single Bond Universal (SBU) to prepare low CTE adhesives. The CTE value of the adhesives can be adjusted low to 6.5 ppm/K, which is much lower than that of pure SBU. Mimicking the real applying conditions, the composite resin columns were bonded to the zirconia ceramics as a dental crown with our designed adhesives, and the shear bond strength test was carried out before and after 10 000 thermal cycles between 5 and 55 °C. The shear bond strength of pure SBU retains 44.7% of its original value after 10 000 thermal cycles, while those low CTE adhesives retain 74.6% and 61.9% of shear bond strength due to less deformation and interfacial stress during thermocycling. The newly designed adhesives provide a persistent way to enhance the shear bond strength and achieve a long lifetime in tooth restoration.
研究领域:
材料科学
·
牙科学
✓ 已验证
DOI
高影响因子
RUSSIAN JOURNAL OF INORGANIC CHEMISTRY
·
2022
·Vol. 67
·期 4
·533-538
·
IF 1.667
Jiang Zhen-Zhen,Liu Gao-Ling,Li Ming-Li,Guo Ya-Fei,Meng Ling-Zong,Duo Ji,Deng Tian-Long
Abstract To better use rare earth element resources in geothermal water, it is essential to understand the volumetric property and the ion-interaction of the rare earth element aqueous solution systems. In this paper, the densities of aqueous Y 2 (SO 4 ) 3 from 0.00405 to 0.04071 mol kg −1 at 283.15 to 363.15 K were measured using an Anton Paar Digital vibrating-tube densimeter. Apparent molar volumes ( V ϕ ) and the coefficient of thermal expansion (α) were obtained based on the experimental density data, and the diagrams of the apparent molar volume and coefficient of thermal expansion of Y 2 (SO 4 ) 3 (aq) against temperature ( T ) and molality ( m ) in the binary system were revealed. The Pitzer single-salt parameters \({{(\beta }}_{{{\text{MX}}}}^{{(0)v}},{{\beta }}_{{{\text{MX}}}}^{{(1)v}},{{\beta }}_{{{\text{MX}}}}^{{(2)v}}\,\,{\text{and}}\,\,C_{{{\text{MX}}}}^{v})\) for Y 2 (SO 4 ) 3 and their temperature-dependent correlation F ( i , p , T ) = a 1 + a 2 ln( T /298.15) + a 3 ( T − 298.15) + a 4 /(620 − T ) + a 5 /( T − 227) (where T is temperature in Kelvin, a i are the correlation coefficients) for Y 2 (SO 4 ) 3 were obtained for the first time.
研究领域:
化学
·
物理化学
·
地质学
✓ 已验证
DOI
高影响因子
JOURNAL OF MATERIALS SCIENCE-MATERIALS IN ELECTRONICS
·
2022
·Vol. 33
·期 26
·21101-21110
·
IF 2.779
Wang Zhaohui,Fang Weishuang,Tang Ying,Xiang Huaicheng,Li Jie,Fang Liang
Ca 3 MZnGe 3 O 12 ( M = Zr, Sn) ceramics crystallized in a cubic garnet structure (A 3 B 2 C 3 O 12 ) with a space group of Ia- 3 d , and promising microwave dielectric properties with low coefficients of thermal expansion ( α L ) were obtained, namely, ε r = 10.5 and 9.3, Q × f = 79,700, and 96,040 GHz, τ f = − 36.1 and − 61.5 ppm/°C, and α L = 4.3 and 4.7 ppm/°C for Ca 3 ZrZnGe 3 O 12 and Ca 3 SnZnGe 3 O 12 , respectively. Bond valence calculation reveals that Ca 3 SnZnGe 3 O 12 exhibits a slight “compressed” effect at A-site and B-site with a slightly negative deviation (Δ ε r ~ − 1.01%) of the porosity corrected ε r (corr) from theoretical ε r (C–M) calculated by the C–M equation, while Ca 3 ZrZnGe 3 O 12 shows a “rattling” effect at the A-site and C-site with a large positive Δ ε r ~ 15.8%, leading to a high ε r , a more close to zero τ f and a lower Q × f value as compared to those of Ca 3 SnZnGe 3 O 12 . The relationship between structure and their intrinsic microwave dielectric properties was investigated by complex chemical bond theory and far-infrared reflectivity spectra.
研究领域:
材料科学
·
物理学
✓ 已验证
DOI
高影响因子
POLYMER SCIENCE SERIES A
·
2023
·Vol. 64
·期 6
·653-661
·
IF 1
Jiang Taijun,Peng Jun,Wang Jin,Yang Jun,Zeng Guangsheng
Abstract The aim was to prepare copolyimide (BPDA/PMDA-PDA) films of low thermal expansion coefficient by incorporating 1,2,4,5-benzenetetracarboxylic anhydride (PMDA) into polymer backbones 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA)/ p -phenylenediamine (PDA). FTIR and WAXD were used to explore the chemical and physical microstructure of the PIs films. DMA, TMA and TGA were used to characterize the mechanical and thermal performance of the PIs film respectively. The results show that the smectic structure of the film was destroyed by introducing rigid PMDA groups. The free volume fraction of polymers reached its maximum value when 40 wt % PMDA was added. The glass transition temperature of the polymers increased from 330 to 430°C and the thermal decomposition temperature declined slightly with the addition of PMDA. The inflection point in thermal expansion coefficient (CTE) of the BPDA-PDA polymers in TMA test reached as high as 470°C. The glass transition temperature of the polymers increased but the service temperature range narrowed with the addition of PMDA. The optimized PMDA concentration to obtain a best CTE was 5% as was revealed by the experimental results. The insights obtained from the experiments indicated that excessive introduction of PMDA into the polymers could increase the glass transition temperature significantly. However, the operating temperature range may be reduced. This research could offer practical and valuable references to the application for co-PI films.
研究领域:
材料科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2020
·
IF 2.369
Jiaojiao Chen,Wanjing Cui,Yafei Guo,Lingzong Meng,Hongfang Hou,Tianlong Deng
Densities of the binary systems (NaI + H2O) and (NaIO3 + H2O) were measured by an accurate Anton Paar Digital vibrating-tube densimeter at temperature intervals of 5 K ranging from 283.15 to 353.15 K at ambient pressure and molalities of sodium iodide and sodium iodate ranging from 0.16764 to 2.15208 and 0.02252 to 0.15952 mol kg–1, respectively. Based on the experimental density data of the binary systems (NaI + H2O) and (NaIO3 + H2O), thermal expansion coefficient (α) and apparent molar volume (Vϕ) are obtained using an empirical equation calculation, and the diagram for the relationship between temperature and molality was plotted. According to the Pitzer ion-interaction model of the apparent molar volume, Pitzer single salt parameters β(0)v M.X, β(1)v M.X, and Cv M.X and their correlation coefficients ai of the temperature-dependent equation f(i, p, T) = a1 + a2ln(T/298.15) + a3(T – 298.15) + a4/(620 – T) + a5/(T – 227) (where T is the temperature in Kelvin and ai values are the correlation coefficients) for NaI and NaIO3 were first obtained by the least-squares method. The obtained apparent molar volumes agree well with the experimental values, and these results indicated that the single salt parameters and the temperature-dependent formula obtained in this work were reliable.
研究领域:
化学
·
物理化学
✓ 已验证
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2024
·
IF 5.1
Bo Wang,Ziyan Zhao,Zihao Pan,Xuejian Liu,Zhengren Huang,Yan Liu
The ZnO–Al 2 O 3 –B 2 O 3 –SiO 2 (ZABS) glass powder was designed and innovatively employed to join AlN ceramics. The crystallization, thermal expansion and wettability behavior of the ZABS glass and glass-ceramic were investigated. The results shows that Zn 3 B 2 O 6 , ZnSiO 4 and Zn 4 B 6 O 13 were precipitated after heat treatments at different temperature, respectively, resulting in a variation in the coefficient of thermal expansion (CTE) of the ZABS glass ceramic. Then guided by the wetting behavior on the AlN ceramic substrate, the joining of the AlN ceramics by ZABS glass at various temperatures and holding times were conducted. Notably, Zn 3 B 2 O 6 was identified to be the primary product in the joints bonded at temperature of 700–800 °C due to the crystallization within the glass and no discernible reaction was observed between the substrate and the interlayer, while ZnSiO 4 was observed at the periphery of Zn 3 B 2 O 6 after 750 °C. Moreover, the crystalline phase Zn 3 B 2 O 6 gradually grew with the temperature and holding time increasing as the glassy phase gradually diminished, resulting in a reduction of the strength and reliability of the joints. The optimal flexural strength of the joints was 156 ± 11MPa at 700 °C for 30min. The reason for the high strength can be attributed to the interactions between the glass precipitated crystalline phase interlocking each other and the glass phase tightly bonded with the crystalline phase.
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
POLYMER COMPOSITES
·
2025
·
IF 4.7
Xiaolong Shi,Hongbo Zou,Lianjie Yuan,Benshuai Chen,Ziang Zhang,Bin Lin,Shuai Yan
Mineral castings are used in the fabrication of precision measurement and machining platforms due to their favorable material properties. However, their high resin contents result in high coefficients of thermal expansion (CTE) and wear rates. This study introduces a novel mineral casting material incorporating β-eucryptite, an additive with negative thermal expansion (NTE). The effects of varying β-eucryptite contents on the thermal expansion and tribological properties of the mineral casting were investigated. Results demonstrated that the addition of β-eucryptite reduced the CTE of the mineral casting by 42.21% and achieved a low thermal diffusivity (Dmin = 0.61 mm 2 /s). Additionally, it decreased the wear rate by 73.83%. The experiment verified the effect of thermal expansion on the wear performance of materials. By reducing the expansion caused by frictional heat, the variation in surface roughness at the contact interface was minimized, leading to a reduction in wear. Highlights The addition of β-eucryptite reduces the CTE by 42.21%. Thermal diffusivity of mineral castings is 96.87% lower than that of cast iron. The addition of β-eucryptite reduces the wear rate by 73.83%. Low coefficient of thermal expansion reduces the wear rate.
研究领域:
材料科学
·
热力学
·
摩擦学
✓ 已验证
产品关联
DOI
高影响因子
CERAMICS INTERNATIONAL
·
2025
·
IF 5.6
Mengting Jiang,Chenying Shi,Yuling Liu,Xiaopeng Li,Tengfei Deng
The mechanism of Mg 2+ introduction on the thermal expansion properties of Al 2 TiO 5 ceramics was elucidated through experimental characterization and theoretical calculation for Mg x Al 2(1-x) Ti 1+x O 5 (x = 0, 0.25, 0.50, 0.75). Results showed that as x increased from 0 to 0.75, the calculated thermal expansion coefficient (single-crystal) exhibited minimal variation, while the apparent thermal expansion coefficient (polycrystalline) increased from 0.09 × 10 -6 K -1 to 3.85 × 10 -6 K -1 (1000 °C). The low apparent thermal expansion of Al 2 TiO 5 (x = 0) was attributed to microcrack healing and pore compensation effects. For x = 0.75, the enhanced apparent thermal expansion was correlated with reduced microcrack formation and improved densification. The incorporation of Mg 2+ reduced octahedral distortion and lattice stiffness, thereby suppressing transverse vibrations of bridging oxygen atoms and contraction along the c-axis. This reduced thermal expansion anisotropy and minimized microcrack formation. Additionally, as Mg 2+ content increased from x = 0 to x = 0.75, the porosity reduced from (11.23 ± 0.13) % to (3.96 ± 0.24) %, thereby weakening the pore compensation effect. These findings provide valuable insights for designing Al 2 TiO 5 -based ceramics with low thermal expansion.
研究领域:
材料科学
·
无机非金属材料
·
热物理性能
✓ 已验证
产品关联
DOI
高影响因子
Materials
·
2025
·Vol. 18
·期 9
·2117
·
IF 3.2
Jiaxiong Li,Muqing Hou,Haiyuan Chen,Huan Yu,Jixue Zhou,Jianhua Wu,Xitao Wang
Al/diamond composites are considered a new generation of potential thermal management materials. In this study, the uniform B coating on the surface of diamond particles was prepared by the vacuum thermal diffusion method. Subsequently, Al matrix composites reinforced with B-coated diamond particles were produced by the gas pressure infiltration method. The plating time was varied from 0 to 120 min to investigate the effect of B coating on the thermal conductivity and thermal expansion of the Al/B-diamond composites. The thermal conductivity for the Al/B-diamond composites increased from 422 W/m·K to 562 W/m·K with prolonged plating time from 0 to 90 min. Correspondingly, the coefficient of thermal expansion was tailored from 7.0 × 10−6/K to 5.8 × 10−6/K. The enhanced thermal conductivity and decreased coefficient of thermal expansion were attributed to strong interfacial bonding in Al/B-diamond composites. The results indicate that the appropriate thickness of B coating is a viable method to improve interfacial bonding between the Al matrix and B-coated diamond particles.
研究领域:
材料科学
·
热管理技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）