電漿浸沒離子注入 (PIII) 氮化技術與傳統氮化技術比較具有節省時間、減少變形與操作溫度較低等優點適合應用於牙科挫針之切削率提升研究。PIII 實驗將挫針分為對照組、氮化 1 小時與氮化 2 小時等三組，氮化條件控制在氮氣流量為100 sccm、氮化溫度 25℃、偏壓 20 kV與頻率 500 Hz等條件。將改質完成的試片透過機械性質量測、成分縱深分析與平均切削重量 (average removed mass) 量測等方式，探討不同氮化時間對於挫針的改質硬度與切削率的影響。研究顯示經過PIII 氮化處理之挫針，機械性質明顯比未經過氮化處理之挫針增加，且由機械性質分佈曲線可知硬度與楊氏模數增加區域約為 100 nm左右。PIII氮化 2小時的表層氮濃度與硬度值之峰值、峰值位置與分佈範圍較 1 小時為大，顯示硬度曲線的變化是受到氮原子縱深分佈的影響。牙科挫針的平均切削重量變化受到表面微刀紋的影響，PIII氮化 1小時可以增加表面微刀紋之硬度，增加挫削的效果，但是 2小時的氮化則會因為熱軟化與電漿轟擊的作用而鈍化微刀紋，減少平均切削重量。

Plasma immersion ion implantation nitriding (PIII&N) process has several
advantages comparing with traditional nitriding method. They are short operation times, less heat deformation of product and low operating temperature, etc, and have potential for modifying the surfaces of dental drills to improve their performances. These dental drills for experiment were divided into three groups including non-nitriding drills and
treated by PIII nitridation at 1 hour and 2 hours, respectively. During PIII nitridation, the flow rate of nitrogen (N2) at 100 sccm, temperature at 25℃, voltage of bias at 20 kV and frequency at 500 Hz were conducted. Profile measurement of hardness, Young’s modulus and chemical elements and cutting-efficiency test were used to investigate the variation of nitrided time vs. mechanical properties. The experimental
results show that both of the hardness and the Young’s modulus of nitrided drills are evidently higher than that of untreated drills. The region of increasing in the hardness and the Young’s modulus is about 100 nm. The peak value and position and the distribution range of nitrogen concentration and surface hardness of nitrided drills after 2 hours PIII treatment are higher than that after 1 hour treatment. It appears that the profile of hardness varies with nitrogen distribution. The micro-pattern on the surface of drill is an important factor in affecting the cutting efficiency. Drills treated by PIII nitriding in 1 hour can increase the hardness of micro-pattern, and thus increase the cutting efficiency. But the other drills treated by PIII in 2 hrs did not improve their cutting efficiency. This is because the heat and ion bombardment from plasma treatment with longer time soften the pattern on drill surface, which decreases the cutting efficiency.