Fabrication of β″‐alumina films as a thermoelectric material by thermal plasma processing

Abstract

The fabrication of b -alumina films as thermoelectric materials was investigated by thermal plasma processing based on the forced constrictive-type reactor. Under both atmospheric and low pressures, b -alumina films were synthesized successfully from a mixed powder of a-Al 2 O 3 , Na 2 CO 3 and MgO. The jet powder and substrate position strongly affect the properties of plasma-processed b -alumina, which were found to be correlated with jet temperature. For both pressures, the films show good thermoelectric properties.

Effect of torch power on the microstructure of plasma sprayed Al2O3 coatings

“…J.T. Kim et al . demonstrated that the increase of the plasma temperature increases the number and intensities of β ‐alumina and β ‐alumina peaks in the XRD diffraction patterns.…”

“…Plasma spraying is currently the most popular technique used commercially to produce various ceramic or composite coatings on metallic surfaces. Plasma sprayed alumina and its composite coatings have been widely used for structural applications in order to improve resistances to corrosion, oxidization, wear, erosion, etc . Because of its hardness and good electrical insulation, alumina is used as a top coat for insulated metal substrates in automotive applications .…”

Preparation of Na-beta″-alumina film by tape casting process

“…According to a previous report, 7 a two-step-synthesis procedure was applied to prepare the betaalumina powder. Firstly, two kinds of precursors of NaAl 5 17 . The mixture was used as the raw material of the slurry for the tape casting.…”

“…4 More recently, Kim et al have fabricated Na-beta -alumina films by thermal plasma processing. 5 However, the mentioned methods displayed some disadvantages, such as high cost, complicated equipments and unsuitability for large-scale production. Compared with these methods, tape casting is a cost-effective ceramic forming * Corresponding author.…”

Synthesis of nano-Na-β″/β-Al2O3 powders by a citrate complex process

“…Because of its high performances, Na-␤ /␤-alumina is suitable for use as ceramic electrolytes in many electrochemical devices, such as sodium sulfur batteries, alkaline metal thermoelectric converters, sodium sensors and electrochromic displayers [1][2][3][4].…”