On thermal stability of plates with functionally graded coefficient of thermal expansion

2016 ◽  
Vol 60 (2) ◽  
pp. 313-335 ◽  
Author(s):  
Abdelmoumen Anis Bousahla ◽  
Samir Benyoucef ◽  
Abdelouahed Tounsi ◽  
S.R. Mahmoud
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Functionally Graded ◽  
Thermal Stability Of

scholarly journals Strengthening Thermal Stability in V2O5-ZnO-BaO-B2O3-M(PO3)n Glass System (M = Al, Mg) for Laser Sealing Applications

2021 ◽  
Vol 11 (10) ◽  
pp. 4603
Author(s):  
Soyoung Kim ◽  
Karam Han ◽  
Seonhoon Kim ◽  
Linganna Kadathala ◽  
Jinhyeok Kim ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Bond Strength ◽  
Coefficient Of Thermal Expansion ◽  
Glass Frit ◽  
Glass System ◽  
Fiber Types ◽  
Hermetic Sealing ◽  
Doped Glasses ◽  
Glass Panels

Today, the most common way of laser sealing is using a glass frit paste and screen printer. Laser sealing using glass frit paste has some problems, such as pores, nonuniform height, imperfect hermetic sealing, etc. In order to overcome these problems, sealing using fiber types of sealant is attractive for packaging devices. In this work, (70-x)V2O5-5ZnO-22BaO-3B2O3-xM(PO3)n glasses (mol%) incorporated with xM(PO3)n concentration (where M = Mg, Al, n = 2, 3, respectively) were fabricated and their thermal, thermomechanical, and structural properties were investigated. Most importantly, for this type of sealing, the glass should have a thermal stability (ΔT) of ≥80 °C and the coefficient of thermal expansion (CTE) between the glass and panel should be 1.0 ppm/°C. The highest thermal stability ΔT of the order of 93.2 °C and 112.9 °C was obtained for the 15 mol% of Mg(PO3)2 and Al(PO3)3 doped glasses, respectively. This reveals that the bond strength and connectivity is more strongly improved by trivalent Al(PO3)3. The CTE of a (70-x)V2O5-5ZnO-22BaO-3B2O3-xAl(PO3)3 glass system (mol%) (where x = 5–15, mol%) is in the range of 9.5–15.5 (×10−6/K), which is comparable with the CTE (9–10 (×10−6/K)) of commercial DSSC glass panels. Based on the results, the studied glass systems are considered to be suitable for laser sealing using fiber types of sealant.

Synthesis and properties of low coefficient of thermal expansion copolyimides derived from biphenyltetracarboxylic dianhydride with p-phenylenediamine and 4,4′-oxydialinine

e-Polymers ◽  
2016 ◽  
Vol 16 (4) ◽  
pp. 295-302 ◽  
Author(s):  
Yonglin Lei ◽  
Yuanjie Shu ◽  
Jinhua Peng ◽  
Yongjian Tang ◽  
Jichuan Huo
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Coefficient Of Thermal Expansion ◽  
Thermomechanical Analysis ◽  
Amic Acid ◽  
Molar Ratio ◽  
Structure And Property ◽  
Property Relations ◽  
Ft Ir ◽  
Biphenyltetracarboxylic Dianhydride

AbstractA series of copolyimides were prepared by thermal imidization of poly(amic acid)s (PAAs) derived from 3,3′,4,4′-biphenyltetracarboxylic dianhydride (s-BPDA), 2,3′,3,4′-biphenyltetracarboxylic dianhydride (a-BPDA), p-phenylenediamine (PDA) and 4,4′-oxydialinine (4,4′-ODA) commonly used for the production of commercial polyimides. The flexible copolyimide films were obtained from that the molar ratio of s-BPDA, a-BPDA, PDA and 4,4′-ODA was 9:1:8:2 (Co-PIs-3), 8:2:9:1 (Co-PIs-5) and 8:2:8:2 (Co-PIs-6). These obtained copolyimide films were characterized by Fourier transform-infrared spectroscopy(FT-IR), wide angle X-ray (WAXD), Thermogravimetric (TG), dynamic mechanical thermal analysis (DMA), thermomechanical analysis (TMA), field-emission scanning electron microscopy (FE-SEM) and mechanical properties measurement. The results showed that three copolyimides remained semi-crystalline and exhibited high glass transition temperature (Tg), high thermal stability, great ultimate tensile strength and low coefficient of thermal expansion (CTE). The Co-PIs-5 had lower crystallinity, lower CTE, greater elongation at break, higher Tg and thermal stability and the greater dense extent, compared with Co-PIs-3 and Co-PIs-6. Structure and property relations of the prepared polyimides were also briefly discussed. The results revealed that the copolymerization of s-BPDA/PDA with a small number of 4,4′-ODA/a-BPDA was a useful means for enhancing flexibility without sacrificing low CTE.

Comparison study of carbon black (CB) used as conductive filler in epoxy and polymethylmethacrylate (PMMA)

2016 ◽  
Vol 36 (4) ◽  
pp. 391-398 ◽  
Author(s):  
Jin-Luen Phua ◽  
Pei-Leng Teh ◽  
Supri Abdul Ghani ◽  
Cheow-Keat Yeoh
Keyword(s):  
Thermal Stability ◽  
Electrical Conductivity ◽  
Fracture Toughness ◽  
Thermal Expansion ◽  
Carbon Black ◽  
Coefficient Of Thermal Expansion ◽  
Conductive Filler ◽  
Filler Loading ◽  
Comparison Study ◽  
Thermoset Epoxy

Abstract A comparison study between carbon black (CB) filled thermoset (epoxy) and thermoplastic, polymethylmethacrylate (PMMA), was done in this research. CB was introduced as the conductive filler in epoxy and PMMA at different filler loading, which ranged from 5 vol.% to 20 vol.%. The physical, mechanical, electrical and thermal stability properties were investigated. The incorporation of CB into both epoxy and PMMA increased the density, improved the thermal stability and electrical conductivity of the composites, reduced the coefficient of thermal expansion and weakened the flexural and fracture toughness properties of the composites.

Effect of metal catalyst thermal expansion on thermal stability of synthetic diamonds

2012 ◽  
Vol 53 (1) ◽  
pp. 409-415 ◽  
Author(s):  
Mykola V. Novikov ◽  
Anatoliy L. Maystrenko ◽  
Volodymyr I. Kushch
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
Metal Catalyst ◽  
Synthetic Diamonds ◽  
Thermal Stability Of

scholarly journals Thermally stable and highly efficient red-emitting Eu3+-doped Cs3GdGe3O9 phosphors for WLEDs: non-concentration quenching and negative thermal expansion

2021 ◽  
Vol 10 (1) ◽  
Author(s):  
Peipei Dang ◽  
Guogang Li ◽  
Xiaohan Yun ◽  
Qianqian Zhang ◽  
Dongjie Liu ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Thermal Expansion ◽  
White Light ◽  
Coefficient Of Thermal Expansion ◽  
Internal Quantum Efficiency ◽  
Negative Thermal Expansion ◽  
Concentration Quenching ◽  
Excellent Thermal Stability ◽  
Red Phosphor ◽  
Highly Efficient

AbstractRed phosphor materials play a key role in improving the lighting and backlit display quality of phosphor-converted white light-emitting diodes (pc-WLEDs). However, the development of a red phosphor with simultaneous high efficiency, excellent thermal stability and high colour purity is still a challenge. In this work, unique non-concentration quenching in solid-solution Cs3Gd1 − xGe3O9:xEu3+ (CGGO:xEu3+) (x = 0.1–1.0) phosphors is successfully developed to achieve a highly efficient red-emitting Cs3EuGe3O9 (CEGO) phosphor. Under the optimal 464 nm blue light excitation, CEGO shows a strong red emission at 611 nm with a high colour purity of 95.07% and a high internal quantum efficiency of 94%. Impressively, this red-emitting CEGO phosphor exhibits a better thermal stability at higher temperatures (175–250 °C, >90%) than typical red K2SiF6:Mn4+ and Y2O3:Eu3+ phosphors, and has a remarkable volumetric negative thermal expansion (coefficient of thermal expansion, α = −5.06 × 10−5/°C, 25–250 °C). By employing this red CEGO phosphor, a fabricated pc-WLED emits warm white light with colour coordinates (0.364, 0.383), a high colour rendering index (CRI = 89.7), and a low colour coordinate temperature (CCT = 4508 K). These results indicate that this highly efficient red-emitting phosphor has great potential as a red component for pc-WLEDs, opening a new perspective for developing new phosphor materials.

High thermal stability of core–shell structures dominated by negative interface energy

2017 ◽  
Vol 19 (13) ◽  
pp. 9253-9260 ◽  
Author(s):  
Yong-Fu Zhu ◽  
Ning Zhao ◽  
Bo Jin ◽  
Ming Zhao ◽  
Qing Jiang
Keyword(s):  
Thermal Stability ◽  
Heat Capacity ◽  
Thermal Expansion ◽  
Interface Energy ◽  
High Thermal Stability ◽  
Shell Structures ◽  
Atomic Diffusion ◽  
Core Shell ◽  
Thermal Stability Of

Superheating of the low-Tm(∞)-core is induced by the negative interface energy, improving thermal expansion, atomic diffusion and heat capacity accordingly.

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