scholarly journals Effect of rare earth oxide CeO2 on the anodic bonding performance of PEG-based MEMS encapsulation materials

2021 ◽  
Vol 13 (3) ◽  
pp. 168781402110077
Author(s):  
Chao Du ◽  
Cuirong Liu ◽  
Xu Yin ◽  
Haocheng Zhao

Herein, we synthesized a new polyethylene glycol (PEG)-based solid polymer electrolyte containing a rare earth oxide, CeO2, using mechanical metallurgy to prepare an encapsulation bonding material for MEMS. The effects of CeO2 content (0–15 wt.%) on the anodic bonding properties of the composites were investigated. Samples were analyzed and characterized by alternating current impedance spectroscopy, X-ray diffraction, scanning electron microscopy, differential scanning calorimetry, tensile strength tests, and anodic bonding experiments. CeO2 reduced the crystallinity of the material, promoted ion migration, increased the conductivity, increased the peak current of the bonding process, and increased the tensile strength. The maximum bonding efficiency and optimal bonding layer were obtained at 8 wt% CeO2. This study expands the applications of solid polymer electrolytes as encapsulation bonding materials.

2018 ◽  
Vol 96 (7) ◽  
pp. 786-791 ◽  
Author(s):  
Kemal Ulutaş ◽  
Ugur Yahsi ◽  
Hüseyin Deligöz ◽  
Cumali Tav ◽  
Serpil Yılmaztürk ◽  
...  

In this study, it was aimed to prepare a series of PVdF-co-HFP based electrolytes with different LiClO4 loadings and to investigate their chemical and electrical properties in detail. For this purpose, PVdF-co-HFP based electrolytes with different LiClO4 loadings (1–20 weight %) were prepared using solution casting method. X-ray diffraction (XRD), differential scanning calorimetry, and thermogravimetric (TGA) –differential thermal and dielectric spectroscopy analysis of PVdF-co-HFP/LiClO4 were performed to characterize their structural, thermal, and dielectric properties, respectively. XRD results showed that the diffraction peaks of PVdF-co-HFP/LiClO4 electrolytes broadened and decreased with LiClO4. TGA patterns exhibited that PVdF-co-HFP/LiClO4 electrolytes with 20 wt % of LiClO4 had the lowest thermal stability and it degraded above 473 K, which is highly applicable for solid polymer electrolytes. Dielectric constant, dielectric loss, and conductivities were calculated by measuring capacitance and dielectric loss factor of PVdF-co-HFP/LiClO4 in the range from 10 mHz to 20 MHz frequencies at room temperature. In consequence, conductivities of PVdF-co-HFP/LiClO4 increased significantly with frequency for low loading of LiClO4 while they only slightly changed with higher LiClO4 addition. On the other hand, dielectric constant values of PVdF-co-HFP/LiClO4 films decreased with frequency whereas they rose with LiClO4 addition. The dielectric studies showed an increase in dielectric constant and dielectric loss with decreasing frequency. This result was attributed to high contribution of charge accumulation at the electrode–electrolyte interface. The electrolyte showed the maximum conductivity of 8 × 10−2 S/cm at room temperature.


2010 ◽  
Vol 129-131 ◽  
pp. 526-530 ◽  
Author(s):  
Salmiah Ibrahim ◽  
N.S. Mohamed

ZrO2 nano sized filler of different amounts is introduced into solid polymer electrolytes of PVDF-HFP-LiCF3SO3-ZrO2. It is observed that the conductivity of the electrolytes varies with ZrO2 content and temperature. The highest room temperature conductivity achieved is in the order of 10-3 S cm-1 which is an increase of seven orders of magnitude compared to the conductivity of PVDF-HFP-LiCF3SO3 (without filler). The temperature dependent conductivity follows the Vogel Tamman Fulcher relationship which can be described by the free volume theory. Transference number measurements using DC polarization method show that the nanocomposite polymer electrolytes are ionic conductors. Differential Scanning Calorimetry results show that the degree of crystallinity is slightly affected by the addition of ZrO2 nanofiller.


2018 ◽  
Vol 929 ◽  
pp. 116-120
Author(s):  
Jarot Raharjo ◽  
Damisih ◽  
Masmui ◽  
Ade Utami Hapsari ◽  
Asep Riswoko ◽  
...  

Observation on the effects of rare earth impurities on the properties of Ce0.9Gd0.1O0.195 (GDC) composite electrolyte has been performed. Indonesia has abundant rare earth elements especially CeO2, which one of the resources is from monazite mineral. In this study, the GDC powders were synthesized via solid state technique. The two types of precursors were prepared and mixed into planetary ballmill, i.e., CeO2 (Sigma Aldrich) with Gd2O3 (Sigma Aldrich) and CeO2 (non-commercial, local product) with Gd2O3 (Sigma Aldrich), namely GDC commercial and GDC non-commercial, respectively. The composite electrolyte powders calcined at temperature of 800°C in the air atmosphere condition. The composite electrolytes were then characterized in terms of its morphology, elemental, phase structure and thermal properties of the powders. The GDC commercial and non-commercial powders both consist of face centered cubic fluorite ceria structure which was confirmed by X-Ray Diffraction (XRD). The peaks are matching well with the cerium oxide JCPDS card No: 34-394. There are no peaks detected for the gadolinium oxide. It indicates that the dopant ion is fully substituted into the CeO2 lattice. The elemental analysis was performed using X-ray Fluorescence (XRF). The microstructures were observed under Scanning Electron Microscopy (SEM). The thermal properties characterizations were performed by using Thermal Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) from room temperature to 1500°C. Both powders investigated are suitable for electrolyte IT-SOFC based on their physical and thermal characterization. Among the composite electrolytes investigated, the GDC commercial showed the better performance in terms of their physical and thermal properties.


2011 ◽  
Vol 31 (2-3) ◽  
Author(s):  
Udayan De

Abstract Polymer properties are often engineered in desired directions by additives or by irradiations or by both. However, in space and certain other applications, energetic particles or γ-rays may damage the polymeric parts in undesired directions, needing prior radiation damage studies for necessary precautions. Case studies of three completely different polymer-additive composites follow: (1) shielding electromagnetic interference (EMI) by different composites of a polymeric binder, (2) electrical, thermal, mechanical (Young’s Modulus, Y) and positron lifetime (PL) characterizations of solid polymer electrolytes (SPEs), and (3) determination of total free volume and hole size by pressure-volume-temperature (P-V-T) and positron lifetime techniques, respectively, in two types of polymers. One type consists of complexes of poly-(ethylene oxide), PEO, with a suitable salt, PEO-salt SPEs. The other type consists of silica-filled and pure varieties of poly(dimethyl siloxane), PDMS. Melting point and glass transition temperature of these polymers have been determined from PL techniques as well as from differential scanning calorimetry (DSC). Electrical contact problem has been addressed by measuring impedance as a function of pressure, p, and then extracting p=0 values of impedance and Young’s Modulus. These illustrative measurements have been carried out for better characterization of the polymers. DSC thermogram showed that radiation induced changes of melting point of PEO-salt samples are in opposite directions for 160 MeV Ne6+ion and 1.25 MeV γ-ray irradiations. This interesting feature hints at different mechanisms of radiation damage in two cases.


2018 ◽  
Vol 30 (8) ◽  
pp. 986-992 ◽  
Author(s):  
Sandhya Gupta ◽  
Pramod K Singh ◽  
B Bhattacharya

Polymer electrolyte films based on poly(ethylene oxide) doped with salt sodium nitrate and ionic liquid (IL; 1-ethyl 3-methylimidazolium thiocyanate) have been prepared and characterized by differential scanning calorimetry (DSC) and impedance spectroscopy. The relative percentage of crystallinity of polymer electrolytes has been calculated by using DSC thermograms and electrical properties by using impedance spectroscopy. The incorporation of IL in polymer matrix increases the conductivity of polymer electrolyte. The maximum value of ionic conductivity of polymer electrolyte is found to be 1.93 × 10−4 S m−1 with 9 wt% IL.


2020 ◽  
pp. 17-23
Author(s):  
Wendy Zhao ◽  
Xinyi Mei ◽  
Zheng Yue ◽  
Braja K Mandal

A new class of lithium-ion conducting Solid Polymer Electrolytes (SPEs) has been derived from oligomeric Polyethylene Oxide (PEO)-grafted Cross-linked Polystyrene (XPS) microspheres containing one or two lithium sulfonamide moieties. The SPE containing Li:O mole ratio of 1:8 displayed excellent ionic conductivity (in excess of 10-4S/cm at 25ºC) and good electrochemical stability (4.3 volts versus Li/Li+). Thermal properties of these SPEs have also been investigated with Differential Scanning Calorimetry (DSC) and Thermogravimetric Analysis (TGA). These new SPEs possess amorphous character with a glass Transition Temperature (Tg) around 135ºC, and no significant thermal decomposition until 420ºC. Synthesis and characterization including surface morphologies of these SPEs are described.


Author(s):  
Jijeesh Nair ◽  
◽  
Matteo Destro ◽  
Claudio Gerbaldi ◽  
Federico Bella

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