利用常壓介電質放電系統於粉體表面進行含碳材料鍍膜之製程研究

Abstract

本研究利用常壓介電質放電系統於粉體表面進行含碳材料之鍍膜反應。電漿型態依據不同的實驗架設與操作條件可被分為許多不同種類，當一電漿系統的兩電極間存在至少一介電層時，此系統即被稱做DBD；本研究將碳源前驅物通入電漿中，受到電子的作用下，可使前驅物產生裂解反應並於粉體表面進行含碳材料披覆。本實驗透過改變不同實驗架設、碳源前驅物種類、欲進行披覆的粉體種類等，期望能在粉體表面進行均勻之碳材料鍍膜反應。 本研究曾經嘗試以噴流式常壓介電質放電系統、金屬網格式常壓介電質放電系統、封閉式流體化床介電質放電系統以及噴動式流體化床介電質放電系統等裝置來進行粉體之鍍膜實驗，上述實驗裝置均能使流經電漿區域之碳源前驅物在受到電子的作用下，產生裂解反應以及進行沉積作用；而當利用最後一種實驗裝置進行粉體之碳材料披覆時，可得到較為均勻之碳膜沉積，因此，本研究最後選擇以噴動式流體化床介電質放電系統進行粉體之披覆。使用噴動式流體化床介電質放電系統時，藉由施加一振動能量，使粉體於反應器內能順利地循環流動，有利於粉體與電漿所生成之含碳粒子間均勻接觸，故可在粉體表面鍍上一層均勻的含碳材料。當使用可見光拉曼光譜儀對該碳膜進行檢測時，發現有一極強之光激發螢光背景值(photoluminescence background)產生，可知本系統所生成之碳膜具有較高的氫含量，且在傅立葉轉換紅外線光譜檢測中也可看到碳氫鍵結之吸收峰，因此，本研究藉由不同的後處理方式期望使該碳膜中所含氫元素能夠被移除，並提高碳膜中雙鍵sp2 carbon的比例，使粉體表面披覆一層具有良好導電性的碳膜以增加其導電度。本研究在粉體的後處理方面嘗試過常壓DBD電漿、低壓CCP電漿以及高溫熱處理等方式，最後藉由高溫熱處理的方式使粉體中所含氫元素得以移除，且經此製程所得粉體的導電度可提升至多約三千倍。

This study incorporates a dielectric barrier discharge (DBD) system to coat the surface of the powders with carbon films. Different types of plasmas can be categorized according to different experimental setups and operation parameters. A plasma system is called DBD when at least one dielectric layer exists between its two electrodes. When the carbon source flows into the plasma and thereby came under the effect of the energetic particles, it will then decompose and cover the powder surfaces with carbon films. This study aims to achieve successful carbon coating on the powder surfaces through different experimental setups, carbon sources, and the host particles. This study has tried to achieve carbon coating with jet-type atmospheric pressure DBD plasma, mesh-type atmospheric pressure DBD plasma, fluidized bed atmospheric pressure DBD plasma system, and spouted bed atmospheric pressure DBD plasma system, all four of which are able to produce plasma through which the carbon sources would decompose and deposit. However, the last one is able to coat the powder surface with a uniform carbon film. Therefore, this study chooses spouted bed atmospheric pressure DBD plasma system as the final method to do power coating within gas phase. In the spouted bed atmospheric pressure DBD plasma system, a vibration energy is added to make the host particles circulating smoothly inside the reactor. This circulation allows the host particles to contact the radicals evenly, and thus arrives at ideal carbon coating. Note that the carbon film produced by the DBD system is of a higher hydrogen content. A diagnosis of it with visible Raman spectrometer will produce PL background signals as a result. This study aims at a dehydrogenation and an elevation of sp2 carbon in the carbon film, in hope of improving the conductivity of powders with an ideal conductive carbon coating. In terms of the post-treatment, this study has tried atmospheric pressure DBD plasma device, low pressure capacitively coupled plasma and thermal treatment. The third one can effectively dehydrogenate the carbon film and improve powder conductivity.