摘要
采用X射线衍射（XRD）、能谱分析（EDS）等方法研究脉冲电沉积法制备的纳米晶Ni-Co合金镀层的组织结构和合金成分。测定不同退火温度下纳米晶Ni-Co合金镀层的显微硬度,并着重研究Ni-23.5%Co（质量分数）合金的热稳定性,结果表明：随着退火温度的升高,纳米晶Ni-Co合金在低温退火后显微硬度有所升高,在250℃时达到最高值,然后随退火温度的继续升高而降低。纳米晶Ni-23.5%Co合金镀层的晶粒尺寸逐渐增大,从原始晶粒尺寸13.5nm长大到300℃时的98.5nm,在升温速率为20K.min-1的DSC曲线中,Ni-23.5%Co合金在约300-350℃一直是低能放热,随后出现明显的放热峰,其峰值温度为372℃,放热焓为14.22J·g^-1。通过测定不同升温速率条件下的DSC曲线峰值温度,由Kissinger方程求得纳米晶Ni-23.5%Co合金镀层的晶粒长大激活能为212.5kJ/mol。
Microstructures and composition of nanocrystalline Ni-Co alloy produced by pulse electro- deposition were studied by XRD and EDS. The mierohardness of nanocrystalline Ni-Co alloy annealed at various temperatures was measured and the thermal stability of Ni-23.5%Co（mass fraction） alloy was studied extensively. The results indicated that microhardness of Ni-Co alloys increased slightly after annealing at low temperatures, and reached the maximum at 250℃, then decreased with the in- creasing of the annealing temperatures. The grain size of Ni-23.5%Co alloy increased from 13.5nm to 98. 5nm when the annealing temperature rose to 300℃. The DSC curve obtained at 20 K · min^- 1 heating rate showed low energy exotherm beginning at 300℃ and continuing to 350℃ at which point the main thermal release occurred, reaching peak differential heat flow at 372℃, the release AH was 14. 22J · g^-1. According to the Kissinger equation, the activation energy for grain growth of Ni- 23.5%Co alloy was calculated to be 212.5kJ/mol.
出处
《材料工程》
EI
CAS
CSCD
北大核心
2009年第4期52-56,共5页
Journal of Materials Engineering
基金
福建省自然科学基金资助项目(E0810006)
关键词
脉冲电沉积
Ni-Co合金镀层
热稳定性
激活能
pulse electrodeposition
Ni-Co alloy coating
thermal stability
activation energy
