- 學位論文
電鍍參數對直流電鍍鎳錳合金微結構與機械性質之影響
Effects of Plating Parameters on the Microstructure and Mechanical Properties of DC Electrodeposited Nickel-Manganese Alloy Coating
摘要
鎳錳合金鍍層之性質取決於鍍層成份和微結構，本研究係於胺基磺酸鎳鍍液系統添加錳離子透過直流電鍍製程製備鎳錳合金，探討電鍍製程參數電流密度 (0.2 - 12 A/dm2) 、鍍液成分對於鍍層成份、陰極電流效率、微結構、晶粒尺寸與機械性質之影響。結果顯示鍍層錳含量與陰極電流效率會隨著電流密度增加呈現遞增趨勢，而採用低電流密度所製作鎳錳合金會有壓縮之內應力。由金相腐蝕組織、X光繞射分析、TEM觀察以及極化區線量測等試驗結果發現，鎳錳合金微結構是屬於奈米結晶質的柱狀晶組織，且以優選方位為 (111) 面時擁有較高的硬度值。此外，鍍層晶粒尺寸會隨著錳共鍍量增加呈現細緻化趨勢，進而提升鎳錳鍍層機械強度。 本試驗除了微結構分析以外進而討論平整性試驗、退火熱處理及拉伸試驗，得知電沉積鎳錳合金電鍍還原時讓電場集中現象因錳離子能夠在提高絕緣電阻，減少尖端放電的現象。此外，鎳基合金經退火處理後為達在結晶溫度時晶粒之間產生推擠，也使得硬度值增高至600 kg/mm2 。在拉伸試驗中，亦應證了鎳錳合金在高溫下的熱穩定性，也能夠在退火處理後改變鍍層的機械性質提高鎳錳合金所能使用的環境。
並列摘要
The nature of nickel-manganese alloy coating is determined by its compositions and the associated microstructure. This thesis studied the DC electrodeposition process of nickel-manganese alloy coating from sulphamate bath mixed with manganese ions. The effects of process parameter, such as current density from 0.2 to 12 A/dm2 and electrolyte composition, on the cathodic current efficiency, microstructure, grain size, and mechanical properties were investigated. It was found that both the coating’s manganese content and the cathodic current efficiency increased with the raise in current density. In addition, the internal stress of the deposited coating showed compressive nature at low current densities while changed to tensile one at higher current densities. Moreover, with the metallographic observation, X-ray diffraction measurement, transmission electron microscope (TEM) examination, and polarization curve measurement, the deposited nickel manganese coating consisted of nano-sized columnar grains. The maximum hardness of the coating was associated with (111) preferred orientation in the microstructure. The grain size was refined along with the increase in the manganese content of the coating, which accordingly, raised its hardness and mechanical tensile strength. In addition to the discussion of micro-structural analysis, the study also examines leveling power, annealing, and tensile test. The results indicated that the electric field concentration at the deposition of Ni-Mn Alloy plating reduction due to manganese ions can improve the insulation resistance, reducing the point discharge phenomenon. Besides, Ni-based alloys after annealing is between the grains push at the re-crystallization temperature, the hardness values increased to 600 kg/mm2. Ni-Mn Alloys thermal stability at high temperatures, it is possible to improve the mechanical properties of the coating after annealing treatment of Ni-Mn Alloys.