Effect of annealing temperature on the structure of a ternary aluminate phosphor synthesized via co-precipitation

2019 ◽  
Author(s):  
N. Vinitha ◽  
Jisa Baby ◽  
K. Mini Krishna
2014 ◽  
Vol 692 ◽  
pp. 460-464
Author(s):  
Lian Feng Zhu ◽  
Jue Huang ◽  
Chang Yue Zhang ◽  
Guo Sheng Gai ◽  
You Wei Yao

Gas sensitivity of Sb-doped SnO2 nanograins co-precipitated respectively from ethanol and de-ionized water has been compared. Gas sensing stability of the Sb-SnO2 from ethanol (SnO2-E) was significantly superior to that of Sb-SnO2 from de-ionized water (SnO2-W): working temperature of sensor using SnO2-E was as high as 400 °C, whereas, 250 °C, for sensor using SnO2-W. Furthermore, resistance (R) of SnO2-E was less affected by annealing temperature: the ratio of air resistance annealed at 800 °C (R800) to 400 °C (R400) for SnO2-E and SnO2-W was 8 (4 kΩ/0.5 kΩ) and 1.4×105, 100 MΩ/0.7 kΩ) respectively.


2014 ◽  
Vol 895 ◽  
pp. 287-290 ◽  
Author(s):  
Pradeep Reddy ◽  
Yesu Raja ◽  
M. Ashok

Co2FeO4spinel oxide nano powder was synthesized by co-precipitation process. Samples were annealed at different temperatures of 500, 800 and 900oC and the phase purity were also analyzed. As-prepared sample has two spinel phases and on annealing at 900οC single phase compound formed. The crystallite size of as-prepared is found to be 11.9 nm. The crystallite size increased with increase in annealing temperature to a maximum of 17.4 nm for 900 °C. Samples were subjected to necessary characterization for finding thermal, magnetic and optical band gap.


2020 ◽  
Vol 38 (1) ◽  
pp. 116-121
Author(s):  
Bhargavi Ram Thimmiah ◽  
Gobi Nallathambi

Abstractα-Fe2O3 nanoparticles were synthesized via co-precipitation technique using ferric and ferrous salts and potassium hydroxide as precipitation agents. The samples were calcined at 350 °C, 550 °C and 750 °C for 3 hours. The obtained iron oxide was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and dynamic light scattering (DLS). Crystallinity of the sample was studied by X-ray diffraction. SEM micrographs showed nonuniform size distribution of the particles forming agglomerates. TGA analysis revealed trace amount of weight loss and material stability for the samples calcined at temperatures above 500 °C. DLS results indicated that increasing of annealing temperature resulted in reduction of the particle size and more uniform size distribution. At the maximum annealing temperature of 750 °C, the mean diameter of the particles of 100 nm was observed.


2020 ◽  
Vol 12 (4) ◽  
pp. 555-567
Author(s):  
S. Negi ◽  
A. Sharma ◽  
P. Sharma

In this paper, a systematic investigation has been done to study the effect of variation in annealing temperature on magnetic and optical properties of Mn-doped SnO2. Co-precipitation technique has been used to synthesize Sn1-xMnxO2 samples with low Mn concentration (2 %). Pristine SnO2 is sintered at 350 oC. Mn-doped SnO2 samples are sintered at 350, 450, 550 and 650 oC. The structures of tetragonal rutile of SnO2 and Mn-doped SnO2 have been confirmed by the XRD pattern. Typical ferromagnetic ordering has been observed for Mn-doped SnO2 samples annealed at different temperatures. However, on increasing the annealing temperature saturation magnetization as well as the coercive field decreases, indicating a crucial phase transformation from ferromagnetism to paramagnetism. UV-Vis spectroscopy shows increase in absorbance and a slight shift in the absorption edge with Mn-doping at increasing annealing temperature indicating shifting of absorption peak towards higher wavelength. Tauc’s plot has been used to find the optical band gap (Eg).


2011 ◽  
Vol 264-265 ◽  
pp. 795-800
Author(s):  
Abolghasem Ataie ◽  
S. Moslemi

La substituted barium hexaferrite Ba1-yFe12LayO19 with 0≤ y ≤0.5 was synthesized by chemical co-precipitation method using aqueous solutions of metallic chlorides at ambient temperature. NaOH was used as a precipitant. The co-precipitated products were annealed at 900 and 1000°C. The effects of La addition on the phase composition, morphology and thermal behavior of samples were studied using XRD, SEM and DTA/TGA, respectively. XRD results indicated that barium hexaferrite forms together with some intermediate phases in samples annealed at 900°C and the amount of intermediate phases decreased significantly by increasing annealing temperature to 1000°C. XRD results also showed that in sample annealed at 1000°C, the crystallite size of magnetic phase decreases from 98 to 64 nm by increasing the amount of La. Thermal analysis (DTA/TGA) implies that formation temperature of barium hexaferrite is increased with addition of La.


2018 ◽  
Vol 34 (4) ◽  
pp. 2060-2067 ◽  
Author(s):  
Meenakshi Bansal ◽  
Praveen Aghamkar ◽  
Dharamvir Singh Ahlawat

Silica coated cobalt ferrite (CoFe2O4:SiO2) nanocomposites were synthesized by co-precipitation technique using metal nitrates as precursors. The as-prepared sample has been further heat treated at 250°C, 500°C,750°C and 1000°C. Their structure and morphology related properties were desirably investigated by XRD, FTIR, TEM characterization techniques. Further, with the help of vibrating sample magnetometer (VSM) the magnetic properties have been successfully analysed. Furthermore, the structure and magnetism related properties of these nanocomposites are also understood with heating effects. With increasing calcinations temperature, crystallite size of CoFe2O4:SiO2 nanocomposites was also found to increase. The room temperature magnetic measurements have shown a strong relation of saturation magnetization, retentivity and coercivity with annealing temperature.


2020 ◽  
Vol 102 ◽  
pp. 106172 ◽  
Author(s):  
N. Premjit Singh ◽  
N. Ramananda Singh ◽  
Y. Rangeela Devi ◽  
Brojendro Singh Sh ◽  
Th. David Singh ◽  
...  

2009 ◽  
Vol 620-622 ◽  
pp. 541-544 ◽  
Author(s):  
Ju An Wang ◽  
Yun Hua Xu ◽  
Qihong Cen ◽  
Xiao Man Zhang ◽  
Ya Ru Cui

The present research describes a simple low-temperature synthesis route of fabricating porous YVO4:Sm nanoplates via a chemical co-precipitation method using commercially available Y2O3, NH4VO3, Sm2O3 and ethylene glycol as the reacting precursors. The as-synthesized YVO4:Sm was thermally treated at 300°C and 600°C for 2 h which is much lower than that of the conventional preparation methods. The obtained samples were characterized by FTIR, XRD, TEM and PL. The photoluminescence measurement revealed that the luminescence intensity was significantly increased with increasing annealing temperature.


Sign in / Sign up

Export Citation Format

Share Document