電漿噴塗法製備無機分離薄膜及其特性分析之研究

Study on the Preparation and Characterization of Inorganic Membrane Using Plasma Spray Coating Technique

熊紀中(Chi-Chung Hsiung)

指導教授 ： 童國倫

中原大學/工學院/化學工程研究所/博士(2010年)

https://doi.org/10.6840/cycu201000940

摘要

本論文主要是以大氣電漿噴塗技術製備陶金薄膜與氧化鋁陶瓷薄膜，探討此技術對於陶金粉體及氧化鋁陶瓷粉體在不同的操作參數下製膜之影響，並對兩者不同粉體所製之塗層進行分析及測試。此外，研究也利用計算流體力學及感光耦合光學儀對電漿燄流結構及飛行顆粒之行為進行解析與偵測，將兩者所得之結果與實驗結果進行分析，藉以充分瞭解噴塗參數對塗層特性之影響。
對於製備陶金薄膜之研究結果顯示，適當的添加金屬粉體可改善純氧化鋁堆疊顆粒所產生的龜裂現象，而在不同比例金屬粉體的添加下，對塗層之特性有顯著的影響。從塗層的晶相分析結果顯示，α相之氧化鋁粉體在電漿噴塗過後會產生γ相的氧化鋁，表示顆粒有發生熔融現象，由熔融態的非晶相再重新固化成γ相。而在顆粒熔融的程度實驗結果顯示，其熔融的程度將隨著電漿功率的提高而增加，球形化(spheroidization)程度明顯。從元素組成分EDX分析結果顯示，鎳-鉻合金粉體在電漿噴塗中有氧化反應的發生。在低電漿功率9 kW下顆粒熔融的程度差，導致沉積效率差，塗層堆疊不均；在高功率21 kW下熔融顆粒噴濺現象明顯，塗層結構亦不完整。而在噴塗距離8和10公分條件下所形成之塗層，由於飛行顆粒在此兩者位置之行為與撞擊力不同，顆粒的堆疊亦產生不同的塗層結構。在塗層過濾性能測試顯示，9 kW功率下形成之塗層其純水透過率雖然較高，但其對粒子阻擋率差。而12~21 kW功率下形成之塗層的阻擋率雖可達90%以上，但其純水透過率太低，與商業用相似孔徑之薄膜比較，仍有一段差距。
為了能提高所製備薄膜之過濾性能，本研究以高溫蒸汽誘導機制(High Temperature Vapor Induced Mechanism, HTVIM)進行多孔性陶瓷薄膜的製備。在不同電漿功率及噴塗距離條件下所產生的塗層表面形態亦不相同，低電漿功率
II
9 kW下顆粒熔融程度低，塗層表面發現仍有基材曝露；在功率15 kW及噴塗距離8公分和功率21 kW及8與10公分兩噴塗距離下形成之塗層，因熔融顆粒喷濺現象明顯，塗層結構並不完整；而在功率15 kW及噴塗距離10公分下所形成之塗層有好的多孔性結構。在30分鐘超音波振盪下，以HTVIM製備的塗層沒有發現有剝落的現象，且在振盪後亦發現塗層結構無明顯改變；而商業膜則發現其分離層產生剝落的情形。在塗層過濾之性能方面，9 kW功率下形成的塗層其粒子阻擋率仍太低，不是好製備條件；其他條件所製備之塗層其純水透過率比商業膜高，對粒子之阻擋率亦可達95%以上。對於噴槍在橫向移動速率與縱向移動距離改變的影響，顯示在橫向速率越快時，沉積效率差；縱向移動距離在1 mm時，所形成之塗層厚度大，過濾阻力亦較高。
以計算流體力學軟體進行電漿噴塗程序之模擬可幫助明白操作參數下的影響，如電漿燄流速度與溫度、飛行顆粒的速度與溫度以及電漿燄流與飛行顆粒之間的相互影響。而感光耦合光學儀則可清楚且正確的偵測飛行顆粒在電漿燄流中行為，對噴塗所產生之塗層特性有更深的瞭解。由於計算流體力學軟體有諸多假設之限制，在未來研究上仍需以更多的實驗對其方程式進行修正，以期模擬之結果能縮小與實際所偵測數據間之誤差。

關鍵字

陶瓷薄膜 ； 陶金 ； 飛行顆粒 ； 電漿燄流 ； 大氣電漿噴塗 ； 計算流體力學

並列摘要

In this study, atmospheric plasma spray (APS) was used for producing cermet and alumina oxide membrane. APS were sprayed for discussing cermet and alumina oxide powder under different spray parameters, and proceeding tests for the coating layer. Besides, computational fluid dynamics and CCD of spray watch were used for analyzing and detecting the in-flight particle characteristics. By comparing with the experiment and simulation results we could realize the influence of spray parameters on coating characteristics totally.
In the results of making cermet membrane, it appealed that adding some metal powder could improve the appearance of cracks when alumina oxide powder only. Besides, there were notable influence on coating characteristics under different addition ratio of metal powder. From the XRD results, after plasma spraying alumina oxide transformed from α-phase to γ-phase, which meant that alumina powder had been melted and had been phase changed. In the experiment of particle melted, it appealed that the melting extent and particle spheroidization arised with the plasma power. Moreover, Ni-Cr mixed powder were oxidized in the plasma process from the EDX analysis results. The particle had been poor melted at low plasma power, which result in low coating efficiency and poor accumulation for coating layer. However, at high plasma power the melted particle splashed, which result in poor accumulation for coating layer as well. There were different coating structure because of different impaction force at spray distance 8 cm and 10 cm. The challenge test appealed that there was higher pure water permeation rate at 9 kW, but the particle rejection was not good. In the other hand, there was higher 90% particle rejection rate at 12 to 21 kW, but the pure water permeation rate was not good. Also, comparing with the commercial membrane, which had same average pore size, it was still inferior.
In order to arise the membrane ability, HTVIM was introduced to make the porous membrane in this study. There were different coating morphology under different plasma power and spray distance. Under low plasma power 9 kW because of poor melt, the surface still existed substrate. In the other hand, the melted particle splashed under plasma power 15 kW with spray distance 8 cm and plasma power 21 kW with spray distance 8 and 10 cm, let the structure incomplete. It had well porous structure under plasma power 15 kW and spray distance 10 cm. Besides, under HTVIM method after ultrasonic vibration for 30 min, the coating layer and coating structure did not peel and change, respectively. But for the commercial membrane, it found out peeling between substrate and coating layer. For the challenge test, it was not a good condition at 9 kW, which had low particle rejection. However, other spray conditions had higher pure water permeation rate than the commercial membrane. The influence of the spray gun moving in vertical and horizontal direction appealed that the faster for spray gun moving in horizontal direction, the poorer coating efficiency. In the other hand, when moving distance set at 1 mm in vertical direction, the coating layer had big thickness and filtration resistance.
It is well to realize the process of plasma spray under various operation conditions using CFD. Such as velocity and temperature of plasma plume, in-flight particles and both of interaction. In addition, CCD of spray watch can immediately diagnose the behavior of in-flight particles in the plasma plume and then comprehend the characterization of the coating layer. It still has some errors due to the insufficient assumptions during the CFD simulation. In the future, we will like to take account of the different stage of in-flight particles during plasma spraying. It anticipates that the results of CFD simulation can close to the experiment.

並列關鍵字

computational fluid dynamics ； atmospheric plasma spray ； in-flight particle ； plasma plume ； cermet ； ceramic membrane

參考文獻

周俊宏，「高溫電漿熔射製備陶瓷膜程序之模擬」，碩士學位論文，私立中原大學化學工程研究所(2007)。

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