PREPARING DOUBLE-BASE THERMO-SENSITIVE CERAMICS WITH NANOPOWDERS

2006 ◽  
Vol 05 (02n03) ◽  
pp. 265-271
Author(s):  
MENG KUI WANG ◽  
YU QIANG YANG

The preparing process and the properties of thick-film double-based thermo-sensitive material were studied. The preparing steps were as follows: (i) preparing Ba 1-x Sr x TiO 3 micro-powders with chemical co-precipitation method; (ii) adding dispersants and surface active agents into crushing medium powders to prepare Ba 1-x Sr x TiO 3 nanopowders; (iii) preparing V 2 O 3-based micro-powders; (iv) mixing Ba 1-x Sr x TiO 3 nanopowders, V 2 O 3-based micro-powders, donor impurities, acceptor impurities and micro additives according to a certain ratio to make thick-film thermo-sensitive ceramic material. The presintering and sintering temperature of the prepared PTC ceramics were both reduced, which is very meaningful in using cheaper SiC instead of more expensive MoSi 2, prolonging the kiln's life, and lowering the production cost. The samples we prepared did not contain PbO , so they are safe to the environment.

Materials ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 3717
Author(s):  
Jae-Young Jung ◽  
Soung-Soo Yi ◽  
Dong-Hyun Hwang ◽  
Chang-Sik Son

The precursor prepared by co-precipitation method was sintered at various temperatures to synthesize crystalline manganese tungstate (MnWO4). Sintered MnWO4 showed the best crystallinity at a sintering temperature of 800 °C. Rare earth ion (Dysprosium; Dy3+) was added when preparing the precursor to enhance the magnetic and luminescent properties of crystalline MnWO4 based on these sintering temperature conditions. As the amount of rare earth ions was changed, the magnetic and luminescent characteristics were enhanced; however, after 0.1 mol.%, the luminescent characteristics decreased due to the concentration quenching phenomenon. In addition, a composite was prepared by mixing MnWO4 powder, with enhanced magnetism and luminescence properties due to the addition of dysprosium, with epoxy. To one of the two prepared composites a magnetic field was applied to induce alignment of the MnWO4 particles. Aligned particles showed stronger luminescence than the composite sample prepared with unsorted particles. As a result of this, it was suggested that it can be used as phosphor and a photosensitizer by utilizing the magnetic and luminescent properties of the synthesized MnWO4 powder with the addition of rare earth ions.


2014 ◽  
Vol 895 ◽  
pp. 319-322
Author(s):  
Lim Kean Pah ◽  
Abdul Halim Shaari ◽  
Chen Soo Kien ◽  
Chin Hui Wei ◽  
Albert Gan ◽  
...  

In this work, we report the effect of sintering temperature (900°C, 1000°C, 1100°C and 1200°C) on the electrical and magnetotransport properties of polycrystalline La0.67Sr0.33MnO3 (LSMO). Single phase of LSMO hexagonal structure (R-3c) accompanied with minor phases was successfully synthesized by co-precipitation method. With increasing sintering temperature, grain growth was promoted and grain connectivity was improved. It was found that an enhancement of resistivity on smaller grain size was due to larger grain surface over volume (grain boundaries effect). The shifting of the metal-insulator transition (TMI) to higher temperature was also responsible for observed changes in physical properties. TMI of 900°C, 1000°C and 1100°C were 232 K, 278 K and 298 K respectively however 1200°C was out of measurement range (higher than 300 K). In summary, CP900 with smaller grain size distribution (~200 nm) displayed the highest resistivity and MR% of -19.2% (at 80 K, 10 kG).


2011 ◽  
Vol 295-297 ◽  
pp. 700-703
Author(s):  
Sheng Kui Zhong ◽  
Yue Bin Xu ◽  
Yan Wei Li ◽  
Chang Jiu Liu ◽  
Yan Hong Li

LiNi0.4Co0.2Mn0.4O2 sampleswas synthesized via urea co-precipitation method. The XRD, SEM and electrochemical measurements were used to examine the structure,morphology and electrochemical characteristics, respectively. LiNi0.4Co0.2Mn0.4O2 powders show excellent electrochemical performances. The optimum sintering temperature and sintering time are 800°C and 20 h, respectively. The LiNi0.4Co0.2Mn0.4O2 powders shows the discharge capacity of 145.1 mAh·g-1in the range of 3.0-4.5 V at the first cycle, and the discharge capacity remains 132.3 mAh·g-1after 30 cycles. The urea co-precipitation method is suitable for the preparation of LiNi0.4Co0.2Mn0.4O2 cathode materials with good electrochemical performances for lithium ion batteries.


2009 ◽  
Vol 475 (1-2) ◽  
pp. 926-929 ◽  
Author(s):  
P.P. Hankare ◽  
S.D. Jadhav ◽  
U.B. Sankpal ◽  
S.S. Chavan ◽  
K.J. Waghmare ◽  
...  

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