scholarly journals Effects of Processing Parameters on the Synthesis of (K0.5Na0.5)NbO3Nanopowders by Reactive High-Energy Ball Milling Method

2014 ◽  
Vol 2014 ◽  
pp. 1-6 ◽  
Author(s):  
Nguyen Duc Van
Keyword(s):  
Ball Milling ◽  
Processing Parameters ◽  
High Energy ◽  
High Energy Ball Milling ◽  
Mass Ratio ◽  
Stoichiometric Mixture ◽  
Powder Mass ◽  
Milling Method ◽  
Energy Ball ◽  
Carbonato Complex

The effects of ball milling parameters, namely, the ball-to-powder mass ratio and milling speed, on the synthesis of (K0.5Na0.5)NbO3nanopowders by high-energy ball milling method from a stoichiometric mixture containing Na2CO3, K2CO3, and Nb2O5were investigated in this paper. The results indicated that the single crystalline phase of (K0.5Na0.5)NbO3was received in as-milled samples synthesized using optimized ball-to-powder mass ratio of 35 : 1 and at a milling speed of 600 rpm for 5 h. In the optimized as-milled samples, no remaining alkali carbonates that can provide the volatilizable potassium-containing species were found and (K0.5Na0.5)NbO3nanopowders were readily obtained via the formation of an intermediate carbonato complex. This complex was mostly transformed into (K0.5Na0.5)NbO3at temperature as low as 350°C and its existence was no longer detected at spectroscopic level when calcination temperature crossed over 700°C.

Effect of High-Energy Ball Milling on Microstructure and Microwave Absorbing Properties of NdFe Material

2011 ◽  
Vol 311-313 ◽  
pp. 1281-1285 ◽  
Author(s):  
Pei Hao Lin ◽  
Lei Wang ◽  
Shun Kang Pan ◽  
Hua Mei Wan
Keyword(s):  
Ball Milling ◽  
Particle Morphology ◽  
High Energy ◽  
High Energy Ball Milling ◽  
X Ray ◽  
Microwave Absorbing Properties ◽  
Absorbing Materials ◽  
Milling Method ◽  
Energy Ball ◽  
Microwave Absorbing

The NdFe magnetic absorbing materials were prepared by rapid solidification and high-energy ball milling method. The effect of high-energy ball milling on particle morphology, organizational structure and microwave absorbing properties of NdFe magnetic absorbing materials were analyzed with the aid of X-ray diffractometer, scanning electron microscope and vector network analysis. The results show that the Nd2Fe17 and α-Fe phase are refined, the particles become smaller and thinner; the span-ratio of the particles increases along with time during the process of high-energy ball milling; and meanwhile, the frequency of absorbing peak reduces. The absorbing bandwidth broadens as the increase of the time of ball milling, except that of 48h.The minimum reflectance of the powder decreases from -22dB to - 44dB under the circumstances that the time of high energy ball milling reaches 48h and the thickness of the microwave absorbing coating is 1.5mm. But it rebounds to about - 6dB when the time of ball milling reaches 72h.

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