氧化鋁粒子大小對電鍍鎳複合塗層結構與磨耗腐蝕性質之影響

Influence of Al2O3 Particle Size on the Structure and Wear-Corrosion Properties of Electroplating Nickel Composite Coatings

氧化鋁陶瓷粒子為機械、電子、化學工程中常用材料之一，因其具有高硬度及優異的耐腐蝕性。因具有優越之耐腐蝕性，均為重要之生醫植入金屬，但是缺乏耐磨耗腐蝕性。本研究將探討電鍍鎳液中加入不同濃度（5與20 g/L）與粒徑（1μm與20 nm）的氧化鋁粉末，使其共同析鍍於AISI 304不銹鋼與Ti-6Al-4V合金上，以人工體液Hank’s solution水溶液量測鍍膜對AISI 304與Ti-6Al-4V合金的耐腐蝕與磨耗腐蝕的保護性。鍍膜以塊對環（Block-on-ring）表面摩擦方式磨耗，且同時進行電化學腐蝕量測，利用掃描式電子顯微鏡（SEM）、X光能量散射分析儀（EDS）及奈米硬度量測儀進行表面觀察成份之分析及表面硬度比較。不同氧化鋁粒子大小及不同濃度對AISI 304鋼與Ti-6Al-4V合金在使用電鍍鎳／氧化鋁複合鍍層上會有不同之表面改質效應，可使其附著力佳，而且硬度、耐腐蝕及耐磨耗腐蝕性均能有效提昇。研究結果顯示電鍍鎳與氧化鋁複合鍍層，氧化鋁粒子塗覆了鍍層結節狀的界面孔隙，使鍍層更為緻密。而AISI 304不銹鋼及Ti-6Al-4V鈦合金的複合鍍層，在加入奈米氧化鋁濃度為20 g/L時有最佳的耐腐蝕性，此時AISI 304不銹鋼的複合鍍層硬度值高達6.667 GPa，而對於Ti-6Al-4V合金的複合鍍層硬度值也高達6.719 GPa。而抗腐蝕及磨耗腐蝕能力在加入奈米級氧化鋁粉下的電鍍鎳複合鍍層對不銹鋼及鈦合金基材均有明顯的改進效果。

Deposition of nickel coating on substrate, the coatings have been widely used in the oil, chemical, plastic, mechanical, an electronic, military affairs and aviation industries owing to increase the wear, abrasion and corrosion resistance of substrate. The purpose of this study is to investigate the corrosion and wear-corrosion resistance of electrodeposited nickel composite coatings on AISI 304 stainless steel and Ti-6Al-4V alloy containing Al2O3 powder additive of diameter 1 μm and 20~30 nm, and using different concentrations for compared. Surface morphologies, element compositions and surface hardness of the composite coatings are analyzed by scanning electron microscopy (SEM), X-ray energy dispersive analyzer (EDS) and nanoindentation testing system. Electrochemical polarization measurements are performed for analyzing both corrosion and wear-corrosion characteristics under static and wearing conditions, using the block-on-ring surface friction manner to evaluate the wear-corrosion behavior of these composite coatings in Hank’s solution. The friction ring counterpart is made of a sintered Al2O3.
The experimental results indicated that the content of Al2O3 incorporation in electroplating nickel composite coating resulting in a smearing of nodule boundary and void elimination in the deposits. While at the concentration of 20 g/L Al2O3 (20 ~ 30 nm) there is a highest hardness of 6.667 GPa for AISI 304, and also a highest hardness of 6.719 GPa for Ti-6Al-4V alloy. Especially, the electroplating nickel composite coating surface does not show any significant wear-corrosion failure phenomena when the concentration of Al2O3 powder (20 ~ 30 nm) is at 20 g/L.