在導電玻璃上電鍍鈷鉑奈米島團的研究
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2012
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薄膜和奈米島團的製備有很多種方式，其中可以在大氣下進行的方式之一就是電鍍。電鍍薄膜的過程中有許多的變因可以加以探討，本實驗想要建構一套系統化的討論方式，找出電鍍條件和薄膜特性之間的關係。實驗中，控制電鍍液的組成成分，探討的操縱變因為:不同的電鍍方式，而用來測量分析薄膜特性的儀器有: 恆電位儀（potentiostat）、恆電流儀（galvanostat）、螢光元素分析儀（x-ray fluorescence, XRF）、磁光柯爾效應儀（magneto-optical Kerr effect, MOKE）、原子力顯微鏡 （atomic force microscopy），分別就:電鍍時的電流電壓變化分析，電鍍後膜的成分、磁特性、表面形貌結構這幾個面向來探討。
本實驗將鈷鉑薄膜利用化學電鍍的方式鍍在導電玻璃(氧化銦錫ITO)上。電鍍液是由100 mM的硫酸鈷溶液和3.33 mM的氯鉑氫酸加上50.0 mM的硼酸(緩衝液)組合而成。電鍍的方式主要分成兩種，一種是定電壓電鍍法(potentiostatic)，另一種為定電流電鍍法(galvanostatic)。藉由固定電壓觀察電鍍時的電流變化，或是固定電流觀察電鍍時的電壓變化，搭配循環伏安法可以對於實驗結果加以解釋，並進一步地由成分分析和磁特性分析，觀察電流或電壓的大小如何影響鍍膜的成分，而膜的成分和磁特性和表面結構的關係也可以藉此探討出來。
一開始，先做一系列相關鍍液的循環伏安法對照實驗，推測CV圖中特殊還原峰值電壓可能發生的反應，並在這些特別的電壓位置進行定電壓電鍍薄膜；我們選用了-0.45 V、-0.70 V和-0.85 V這三種特別的電壓大小去電鍍薄膜，接著利用元素分析儀討論在不同電壓下鈷鉑的還原比例，在-0.70 V的電壓大小可以得到鈷鉑還原比例約為1:1，並在這個條件下所鍍的薄膜其縱向矯頑力最大；在
-0.45 V的定電壓下電鍍的薄膜出現特殊形狀的磁滯曲線，探究其薄膜結構，則由原子力顯微鏡觀察到薄膜表面有自我叢聚的島狀微結構。
最後利用定電流電鍍法，得到許多呼應定電壓電鍍法的實驗結果；並且可以觀察到利用化學沉積的方式，電鍍出來的薄膜具有多樣性的表面形貌，電壓和電流的些微改變，所鍍出來的薄膜表面形貌即有所不同，所以可以利用改變化學沉積的參數，製作想要鍍的薄膜的表面形貌。
There are many ways to make the thin film and nano cluster. One of them which could be set up in atmosphere is plating. We want to construct an organized system to study the complex rang of plating parameters. In our experiment, the controlled variable is the composition of electroplating solution, and we want to study the physical properties of the film with different electrical variables, such as plating potential and current. We use to measure the properties of the film by potentiostat, galvanostat, x-ray fluorescence ( XRF), magneto-optical Kerr effect (MOKE), atomic force microscopy (AFM). We can get the information of the association between current and potential when plating, the elemental composition, the magnetic properties, and the surface morphology. We make the thin film and nano cluster by electrodepositing the Cobalt-Platinum on ITO (Indium Tin Oxide). There are CoSO4 (aq) in the concentration of 100 mM and H2PtCl6 (aq) in the concentration of 3.33 mM and the H3BO3 (aq) in the concentration of 50.0 mM as a buffer solution in our electroplating solution. We do electroplating with two conditions, one is potentiostatic plating, and the other is galvanostatic plating. When we set the current constant, we observed the changes of the plating potential with time. With the result of the Cyclic Voltammetry, we could explain what may be happened at the special peaks in the current to potential diagram (I-V curve). And finally we could put all the information together to analyze the composition or the magnetic properties etc. At first, we did a series of blank experiments of Cyclic Voltammetry to speculate what chemical reactions occur at the specific peak in the I-V diagram. Then we did electrodepositing right on the peak potential. We chose three kinds of potential to plating the films. Those are -0.45 V, -0.70 V, -0.85 V. When the films had been manufactured, we want to study the proportion of the reduction of Cobalt or Platinum. The experiment result turns out that the films’ consisting ratio of the reduction of Cobalt and Platinum is one to one in the -0.70 V plating potential. Also, we got the biggest coercivity in this condition. In the other plating potential of -0.45 V, we observed a special shape of the hysteresis curve. Exploring what causes the special hysteresis curve, we used the AFM to probe the surface morphology. The morphology of the surface in -0.45 V plating potential is covered with the micro-structure. The micro-structures are clusters which are composed by several nano units. Finally, the results of galvanostatic plating correspond and confirm with the results of potentiostatic plating. There are plenty of surface morphologies when plating with different current or potential. We can use the relationship between the morphology and the plating electrical parameters to make the very film or nano cluster that we want it to be.
There are many ways to make the thin film and nano cluster. One of them which could be set up in atmosphere is plating. We want to construct an organized system to study the complex rang of plating parameters. In our experiment, the controlled variable is the composition of electroplating solution, and we want to study the physical properties of the film with different electrical variables, such as plating potential and current. We use to measure the properties of the film by potentiostat, galvanostat, x-ray fluorescence ( XRF), magneto-optical Kerr effect (MOKE), atomic force microscopy (AFM). We can get the information of the association between current and potential when plating, the elemental composition, the magnetic properties, and the surface morphology. We make the thin film and nano cluster by electrodepositing the Cobalt-Platinum on ITO (Indium Tin Oxide). There are CoSO4 (aq) in the concentration of 100 mM and H2PtCl6 (aq) in the concentration of 3.33 mM and the H3BO3 (aq) in the concentration of 50.0 mM as a buffer solution in our electroplating solution. We do electroplating with two conditions, one is potentiostatic plating, and the other is galvanostatic plating. When we set the current constant, we observed the changes of the plating potential with time. With the result of the Cyclic Voltammetry, we could explain what may be happened at the special peaks in the current to potential diagram (I-V curve). And finally we could put all the information together to analyze the composition or the magnetic properties etc. At first, we did a series of blank experiments of Cyclic Voltammetry to speculate what chemical reactions occur at the specific peak in the I-V diagram. Then we did electrodepositing right on the peak potential. We chose three kinds of potential to plating the films. Those are -0.45 V, -0.70 V, -0.85 V. When the films had been manufactured, we want to study the proportion of the reduction of Cobalt or Platinum. The experiment result turns out that the films’ consisting ratio of the reduction of Cobalt and Platinum is one to one in the -0.70 V plating potential. Also, we got the biggest coercivity in this condition. In the other plating potential of -0.45 V, we observed a special shape of the hysteresis curve. Exploring what causes the special hysteresis curve, we used the AFM to probe the surface morphology. The morphology of the surface in -0.45 V plating potential is covered with the micro-structure. The micro-structures are clusters which are composed by several nano units. Finally, the results of galvanostatic plating correspond and confirm with the results of potentiostatic plating. There are plenty of surface morphologies when plating with different current or potential. We can use the relationship between the morphology and the plating electrical parameters to make the very film or nano cluster that we want it to be.
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Keywords
磁性薄膜, 電鍍, 鈷鉑薄膜, 奈米島團, 磁光柯爾效應, magnetic film, electrodrposition, Cobalt-Platinum thin film, nano cluster, magneto-optical Kerr effect