脈衝式雷射製作氮化鋁層之研究

Abstract

本研究旨在找出雷射氣體氮化參數對氮化鋁品質特性之影響。首先在大氣環境且不添加填料的情況下，採用氮氣與氨氣為反應氣體，利用脈衝式Nd：YAG雷射為能量源，在鋁合金5052上製作氮化鋁層。接著用光學顯微鏡觀察氮化鋁層、量測其厚度，再以SEM、EDS及EMPA分析組織結構及成分。最後利用田口方法設定雷射氣體氮化最適參數，並以變異數分析法進行分析。研究結果顯示，利用前述方法製作的氮化層由淺至深為緻密顆粒狀和鬆散的樹葉狀，其厚度可達14μm。就氮化層含氮量而言，以氨氣進行氮化的效果優於氮氣。經田口方法所得到之最適製作參數為雷射功率40W、脈衝寬度3.7ms、脈衝頻率5Hz、雷射速度1.5cm/min。參數所選之四個因素中，以雷射功率、雷射速度為氮含量影響最重要的因素，其中以雷射功率為最顯著的因素。This study attempted to characterize the effects of the laser gas nitride parameters on the formation of aluminum nitride. By using nitrogen and ammonia as reactors and pulse Nd: YAG laser as laser medium under standard atmosphere condition without filler, the experiments were performed on the aluminum alloy 5052 with Aluminum nitride layers (AlN layers) manufacturing. We studied the surface morphology by Optical Microscope and analyzed the structure and composition by SEM、EDS and EPMA. Taguchi method was selected to set the optimized parameters of laser gas nitride. The analysis of data was carried out by ANOVA. Our results indicate that AlN layers structure from the outside to the inside are dense granularity and loosely leafy, which could reach to 14μm in thickness. The nitrogen content (N-content) of nitride layer made by ammonia is superior to those of nitrogen made. The optimized parameters obtained by Taguchi method are as following: Laser Power 40W, Pulse Width 3.7ms, Pulse Frequency 5Hz, Laser travel speed 1.5cm/min. It is shown that N-content of AlN layers relates mainly to Laser Power and Laser travel speed. Laser power has the central place in aluminum nitride formation.