Characteristics of Nano-Sized Yttria Powder Synthesized by a Polyvinyl Alcohol Solution Route at Low Temperature

2012 ◽  
Vol 12 (1) ◽  
pp. 800-805 ◽  
Author(s):  
Sang-Jin Lee ◽  
Choong-Hwan Jung
Keyword(s):  
Low Temperature ◽  
Polyvinyl Alcohol ◽  
Alcohol Solution ◽  
Solution Route ◽  
Yttria Powder

Ultra-precision grinding of 4H-SiC wafer by PAV/PF composite sol-gel diamond wheel

2021 ◽  
Vol 13 (9) ◽  
pp. 168781402110449
Author(s):  
Kaiping Feng ◽  
Tianchen Zhao ◽  
Binghai Lyu ◽  
Zhaozhong Zhou
Keyword(s):  
Surface Roughness ◽  
Low Temperature ◽  
Polyvinyl Alcohol ◽  
Feed Rate ◽  
Hot Pressing ◽  
Phenolic Resin ◽  
Sol Gel ◽  
Diamond Wheel ◽  
Sic Wafer ◽  
Better Than

To eliminate the deep scratches on the 4H-SiC wafer surface in the grinding process, a PVA/PF composite sol-gel diamond wheel was proposed. Diamond and fillers are sheared and dispersed in the polyvinyl alcohol-phenolic resin composite sol glue, repeatedly frozen at a low temperature of −20°C to gel, then 180°C sintering to obtain the diamond wheel. Study shows that the molecular chain of polyvinyl alcohol-phenolic resin is physically cross-linked to form gel under low-temperature conditions. Tested by mechanical property testing machines, microhardness tester, and SEM. The results show that micromorphology is more uniform, the strength of the sol-gel diamond wheel is higher, the hardness uniformity is better than that of the hot pressing diamond wheel. Grinding experiments of 4H-SiC wafer were carried out with the prepared sol-gel diamond wheel. The influence of grinding speed, feed rate, and grinding depth on the surface roughness was investigated. The results showed that by using the sol-gel diamond wheel, the surface quality of 4H-SiC wafer with an average surface roughness Ra 6.42 nm was obtained under grinding wheel speed 7000 r/min, grinding feed rate 6 µm/min, and grinding depth 15 µm, the surface quality was better than that of using hot pressing diamond wheel.

scholarly journals Aluminum oxide carrier for a catalyst for low-temperature isomerization of hydrocarbons

2020 ◽  
Vol 15 (3) ◽  
pp. 58-69
Author(s):  
N. Tagandurdyyeva ◽  
N. V. Maltseva ◽  
T. A. Vishnevskaya ◽  
V. N. Narayev ◽  
A. Yu. Postnov
Keyword(s):  
Low Temperature ◽  
Polyvinyl Alcohol ◽  
Aluminum Oxide ◽  
High Selectivity ◽  
Ph Value ◽  
Strength Properties ◽  
Isomerization Reaction ◽  
Preparation Conditions ◽  
Constant Ph ◽  
Extrusion Method

Objectives. Determine the necessary conditions for obtaining a granulated η-Al2O3 carrier, investigate its structural and strength properties, and evaluate its activity for the model n-butane isomerization reaction.Methods. Samples containing bayerite structure aluminum trihydroxide were synthesized by precipitation from aqueous solutions of aluminum nitrate with ammonia under isothermal conditions at a constant pH value. The samples of the granulated carrier were obtained using an extrusion method when the composition of molding pastes was varied by tuning the ratio of bayerite- and η-Al2O3 -containing components and introducing polyvinyl alcohol.Results. The influence of the preparation conditions on the structural and strength properties of the active Al2O3 granules is evaluated. Samples of the aluminum oxide carrier were tested for a model reaction of low-temperature isomerization of n-butane, demonstrating a sufficiently high selectivity and reasonable prospects for use as catalysts for low-temperature isomerization of hydrocarbons.Conclusions. Increasing the content of the polyvinyl alcohol in the molding paste from 0.4 to 1.8 wt % is accompanied by an increase in the predominant sizes of the mesopores in the range of 10–50 nm and pores in the range of 50–80 nm, explaining the high values of all recorded parameters for the process of isomerization of n-butane.

Low-Temperature Local Dissipative Processes in Polyvinyl Alcohol

2019 ◽  
Vol 54 (6) ◽  
pp. 815-820 ◽  
Author(s):  
V. A. Lomovskoy ◽  
N. A. Abaturova ◽  
N. Yu. Lomovskaya ◽  
O. A. Khlebnikova
Keyword(s):  
Low Temperature ◽  
Polyvinyl Alcohol ◽  
Dissipative Processes

K2TiO(C2O4)2-mediated synthesis of rutile TiO2 mesocrystals and their ability to assist photodegradation of sulfosalicylic acid in water

RSC Advances ◽  
2014 ◽  
Vol 4 (90) ◽  
pp. 49280-49286 ◽  
Author(s):  
Lu-Lu Lai ◽  
Li-Liang Huang ◽  
Jin-Ming Wu
Keyword(s):  
Photocatalytic Activity ◽  
Low Temperature ◽  
Specific Surface ◽  
Charge Separation ◽  
Atmospheric Pressure ◽  
High Photocatalytic Activity ◽  
Large Specific Surface Area ◽  
Sulfosalicylic Acid ◽  
Temperature Solution ◽  
Solution Route

Flower-like rutile TiO2 mesocrystals were synthesized by a K2TiO(C2O4)2-mediated low temperature solution route under the atmospheric pressure, which exhibited high photocatalytic activity because of the large specific surface area as well as the high charge separation rate inherent from the single crystal nature.

ChemInform Abstract: MoSe2 Nanocrystallites Synthesized at Low Temperature via a Chemical Solution Route.

ChemInform ◽  
2000 ◽  
Vol 31 (49) ◽  
pp. no-no
Author(s):  
S. Bastide ◽  
C. Levy-Clement ◽  
A. Albu-Yaron ◽  
A.-C. Boucher ◽  
N. Alonso-Vante
Keyword(s):  
Low Temperature ◽  
Chemical Solution ◽  
Solution Route ◽  
Chemical Solution Route

ChemInform Abstract: Low-Temperature Solution Route to Molybdenum Nitride.

ChemInform ◽  
2010 ◽  
Vol 30 (5) ◽  
pp. no-no
Author(s):  
Hsin-Tien Chiu ◽  
Shiow-Huey Chuang ◽  
Gene-Hsiang Lee ◽  
Shie-Ming Peng
Keyword(s):  
Low Temperature ◽  
Molybdenum Nitride ◽  
Temperature Solution ◽  
Solution Route
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