熱處理對電鍍鎳微結構與硬度的影響

Effect of Annealing on the Microstructure and Hardness of Sulfamate Nickel Electrodeposits

林招松(Chao-Sung Lin) ； 許倍誠(Pei-Cheng Hsu)

《大葉學報》 10卷1期 (2001/06) Pp. 13-20

https://doi.org/10.7119/JDYU.200106.0013

摘要

本研究從胺基磺酸鎳浴中以電流密度0.5~4.0 A/dm^2 製備鍍鎳層，探討鍍鎳層經200~600℃熱處理1小時後，鍍層微結構與硬度的變化。以穿透式電子顯微鏡分別對鍍鎳層做平面向和橫截面的結晶構造與缺陷分析。實驗結果顯示：不同電流密度下製備的鍍鎳層具有不同的優選方位、結晶大小和缺陷密度，在0.5~4.0 A/dm^2 下製備的鎳層皆呈大晶粒與小晶粒混合的雙集合結構，晶粒大小隨電流密度增加而增加，但其結晶缺陷密度卻隨電流密度增加而減少，高電流密度製備的鎳層晶粒較粗大且其結晶缺陷較少，導致鎳層硬度較低。電流密度小於1.0 A/dm^2時，鍍鎳層結晶優選取向為較弱的〔110〕，鍍層經400℃ 熱處理後有再結晶與晶粒成長的現象，導致硬度急遽下降。當電流密度大於1.0 A/dm^2 時，鍍鎳層呈明顯柱狀晶結構，〔100〕優選取向明顯，鍍層經600℃ 熱處理後鍍層仍保有柱狀晶結構，僅有晶粒成長，鍍層硬度隨熱處理溫度上昇而呈緩慢下降。

關鍵字

胺基磺酸鎳 ； 優選方位 ； 穿透式電子顯微鏡 ； 再結晶 ； 晶粒成長 ； 雙集合結構

並列摘要

Nickel coatings were electrodeposited from a sulfamate bath at current densities ranging from 0.5 to 4.0 A/dm^2. After 1 h of annealing at 200 to 600℃, the microstructural and hardness changes of Ni electrodeposits were investigated. The grain structure and lattice defects of Ni deposits were characterized by plane-view and cross-sectional transmission electron microscopy. Ni deposit textures were measured by the conventional x-ray diffraction technique. Ni plated at distinct current densities exhibited different textures and had different crystalline sizes and densities of lattice defect. That is, the grain size increased and the density of lattice defect decreased with increasing current densities, although all the Ni deposits studied had a bimodal grain structure. The relatively-soft Ni deposited at high current densities arose from their coarse granular structure with fewer lattice defects. The Ni deposited at current densities less than 1.0 A/dm^2 exhibited a weak [110] texture. The [110]-oriented Ni suffered recrystallization and grain growth after 1 h of annealing at 400℃, and its hardness markedly decreased. On the contrary, the Ni deposited at current densities greater than 1.0 A/dm^2 displayed a strong [100] texture, and the deposit suffered a gradual decrease in hardness after annealing up to 600℃ when the Ni deposit retained its columnar granular structure despite the slight grain growth.

並列關鍵字

sulfamate nickel ； texture ； transmission electron microscopy ； recrystallization ； granular growth ； bimodal grain structure