| Abstract |
| In this study, the heating unit of direct-heating method was manufactured as being the thermal spray coating of conductive heating material on the surface of heating unit in order to improve the demerits of indirect-heating method. And Cu-Zu ferrite had the properties of thermal conduction and high electrical resistivity was chosen of the conductive heating material. Cu-Zu ferrite composite powders were fabricated by drum type ball milling. The atmospheric plasma spray(APS) process was used to deposit the coatings of Ni-5.5Al-5Mo powders for the bonding layer, Al_2O_3 powders for the electrical insulating layer and Cu-Zn ferrite composite powders for the electrical heating layer onto the Al substrate. The plasma sprayed coatings were performed the heat-treatment at 300℃, 405℃ and 600℃. In order to evaluate the plasma sprayed coatings performance, the coating powder observated microstructure, XRD analysis and EDX mapping analysis and mechanical and electrical properties of plasma sprayed coatings. In the result of observations of microstructures, mechanical properties and electrical properties, the best sprayed coatings with direct heating unit was concluded the sprayed coatings that was heat-treated at 300℃. |
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| Key Words |
| Cu-Zn ferrite, Plasma spray, Electrical resistivity, Heating unit, Composite powder, Ball milling |
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