經微弧氧化表面處理之5052鋁合金對PBT高分子塑料接合強度影響之研究

Abstract

使用金屬與塑膠接合成為複合式材料作為元件的方式，在現今許多電子產品中被廣泛的應用，早期的接合方法是使用黏著劑或者是溝槽設計，配合嵌入式射出成型，讓塑膠和金屬加以接合，但為了能夠降低成本和簡化製造流程，新的金屬與塑膠的接合技術不斷的推陳出新。 有文獻指出使用表面處理技術對金屬表面進行改質，讓金屬表面產生具有孔洞的粗糙表面有助於塑料與金屬接合，因此這樣的接合技術成為目前一項重點的研究方向。 本實驗是利用兩種電化學表面處理技術，微弧氧化和陽極氧化鋁，對5052鋁合金表面進行改質，觀察處理後各種不同型式的金屬表面氧化薄膜型態，然後再以熱壓接合和嵌入式射出成型等製程，探討不同氧化層薄膜型態在不同接合方式下，5052鋁合金和PBT塑料接合強度的影響。 實驗研究成果顯示，經過表面處理後的金屬，微弧氧化最高的表面孔洞率為20％，陽極氧化鋁則為33％，熱壓接合時微弧氧化試片抗剪強度最高為4MPa，陽極氧化鋁試片則約為7MPa左右，其結果顯示表面孔洞率與接合強度呈現正相關的情況。 而在嵌入式射出成型實驗結果方面，微弧氧化薄膜表面孔洞率相近的情況下，孔徑大小越大，其接合強度越高，微弧氧化試片實驗最高抗剪力強度可達8MPa，陽極氧化鋁強度則為13Mpa左右。 綜和所有實驗結論可以得知，表面孔洞率為影響金屬與塑膠接合強度的主因，若能有效的提升微弧氧化試片的孔洞率，便可以進一步提升接合強度。

Recently‚ electronic products featuring design elements of metal combined with plastic becoming more and more popular. Insert molding techniques for bonding between metal and plastic in early days were made by groove design or adhesive. In order to reduce costs and facilitate manufacturing processes‚ new adhesion technologies have been developed. Past studies show that using surface treatment for modification of the metal surface would let metal surface become rough and porous‚which benefits to making resins interlocking on metal surface. Therefore‚ this kind of bonding technique has become a focus of current research. This research uses two electrical surface-treated techniques, namely Micro Arc Oxidation（MAO）and Anodic Aluminum Oxidation（AAO） to treat Aluminum 5052. Influence of different forms of metal oxide thin film patterns on bonding strength between metal and PBT polymer are discussed. The results showed that the highest porosity created by Micro Arc Oxidation is 20％‚ while Anodic Aluminum Oxidation porosity is 33％. In hot pressing experiments‚ MAO treated test pieces have shear bonding strength up to 4MPa‚ AAO test pieces are about 7Mpa. The Plastic/Metal bonding strength and surface porosity are positively related. The experiment results in insert molding experiments showed that MAO pieces surface have larger pore size‚ thus higher bonding strength. MAO treated test pieces have bonding strength up to 8MPa‚ while AAO test pieces are about 13Mpa. From the experiment results‚ the main factor which influences Plastic/Metal bonding strength is surface porosity. Improving the MAO specimen surface porosity can further enhance the bonding strength.