反応性プラズマによるセラミックスの切断加工

抄録

Cutting characteristics of ceramics (Al₂O₃, ZrO₂ and Si₃N₄) by using localized reactive gas plasma were investigated theoretically and experimentally. Applying a breakdown voltage between two needle shaped Pt electrodes which are facing each other and holding a ceramic material (t0.6-2mm) between them in etching gas (1-2atm), repetitive discharge (1-15kHz) can be induced between the two electrodes along the material surface. Then a linearly localized reactive gas plasma whose diameter is about 40-60μm can be generated along the material surface and cutting process proceeds with the chemical reaction between the material surface and the reactive gas molecules generated in the plasma. Experimental results are as follows. Etching gas, gas pressure, gas flow rate, electrode gap length and resistance of discharge circuit were the parameters changed. Gas pressure was the most effective parameter to increase cutting rate. In the case of Al₂O₃ (t600μm), the cutting rate obtained in 2atm SF₆ gas was 600μm/min. The cutting rate of Si₃N₄ was 2-3 times greater than that of Al₂O₃. ZrO₂ was unable to be cut because a thermally affected layer was generated on the surface along the gas plasma.