二氧化鋯陶瓷具備高硬度、高強度、優異耐磨耗性、耐腐蝕性及良好熱穩定性，廣泛應用於精密模具、電子元件、生醫植體及半導體設備等領域。然而，其材料兼具高脆性與非導電特性，使傳統切削加工易造成刀具磨耗、邊角崩裂及表面裂紋等缺陷，亦難以直接進行穩定放電加工。因此，如何提升二氧化鋯陶瓷之加工效率與加工品質，已成為先進陶瓷製造技術之重要課題。本研究提出磁場輔助添加奈米三氧化二鐵粉之放電加工方法，以三層銅箔作為初始輔助電極，使非導電二氧化鋯表面建立導電條件。加工過程中，外加磁場可藉由勞倫茲力促進放電渣排出及改善極間放電環境，並對電漿通道產生束縛效應，以提升放電能量密度與加工穩定性。此外，介電液中添加之奈米三氧化二鐵粉具半導體特性，有助於促進介電液之絕緣突破，使放電現象趨於穩定，進而提升非導電材料之放電加工能力。本研究加工參數以高壓電流、放電週期時間及低壓電流為主要加工參數，並以加工時間、RMS電流、加工槽深、加工槽寬、電極損耗量及表面粗糙度作為加工品質特性，探討各參數對加工品質特性之影響。 實驗結果顯示，提高高壓電流、放電週期時間及低壓電流皆有助於縮短加工時間，並增加加工槽深與加工槽寬，顯示材料移除效率提升，惟隨放電能量增加，表面粗糙度亦隨之上升，且加工槽入口邊緣破裂與崩落現象更加明顯。綜合加工效率、尺寸精度與表面品質分析後，以高壓電流0.8 A、放電週期時間50 μs及低壓電流1 A為較佳加工參數，可獲得較佳之表面品質、完整之入口輪廓及穩定之加工結果，與先前研究結果相比較，本研究之加工槽寬約減少 12.2%，顯示介電液添加奈米三氧化二鐵粉末並結合磁場輔助加工，可獲得較小之加工槽寬。;Zirconia ceramics exhibit high hardness and strength， excellent wear and corrosion resistance， and superior thermal stability， making them widely used in precision molds， electronic components， biomedical implants， and semiconductor equipment. However， their inherent brittleness and non-conductive nature make conventional machining processes prone to severe tool wear， edge chipping， and surface cracking. Moreover， stable electrical discharge machining (EDM) of zirconia ceramics is challenging to achieve directly due to their insulating characteristics. Thus， improving the machining efficiency and surface quality of zirconia ceramics has become an essential issue in advanced ceramic manufacturing. A magnetic field-assisted powder-mixed electrical discharge machining (PMEDM) method using nano-sized ferric oxide (Fe2O3) powder was proposed in the present study. To establish a conductive layer on the surface of the non-conductive zirconia ceramic， three layers of copper foil were employed as the initial assisting electrode. During machining， the external magnetic field generated a Lorentz force that facilitated debris removal and improved the inter-electrode discharge environment. Meanwhile， the magnetic field exerted a constraining effect on the plasma channel， enhancing discharge energy density and machining stability. Moreover， the nano-sized Fe2O3 powder added to the dielectric fluid exhibits semiconductor characteristics， which facilitate dielectric breakdown of the fluid while stabilizing the discharge process and enhancing the electrical discharge machining capability of non-conductive materials. The machining parameters examined in this study included high voltage
current， pulse duration， and low voltage current. Machining performance was evaluated via machining time， RMS current， Machining depth， kerf width， electrode wear quantity， and surface roughness. The effects of the parameters on machining characteristics were systematically analyzed. Experimental results indicate that increasing the high voltage current， pulse duration， and low voltage current reduced machining time and increased both machining depth and kerf width， indicating improved material removal efficiency. Higher discharge energy also resulted in increased surface roughness and more severe edge chipping and fracture at the kerf entrance. Considering machining efficiency， dimensional accuracy， and surface quality， the optimal machining parameters were determined to be a high voltage current of 0.8 A， a pulse duration of 50 μs， and a low voltage current of 1 A. Superior surface quality， an intact kerf entrance profile， and stable machining performance were achieved under these conditions. Compared to past studies， the kerf width obtained in this study was approximately 12.2 % smaller. This result indicates that the addition of nanosized ferric oxide (Fe2O3) powder to the dielectric fluid combined with magnetic field-assisted EDM contributed to a reduction in kerf width. This study provides a valuable reference for process optimization and future technological development of EDM for non-conductive materials.
