热处理温度对AZ91D化学镀Ni-P镀层性能的影响

利用F106标尺仪、HVS-1000型显微硬度计和PS-16A型电化学测量系统,研究了镁合金AZ91D化学镀Ni-P的结合 强度、镀层显微硬度和极化性能。结果表明,镁合金化学镀镍层的P含量为6．68％(质量分数),与基体结合良好。随着从200 ℃到450℃退火热处理温度的提高,结合力呈现出先减小后快速增大,然后又减小的趋势,在350℃附近可达最大结合强 度3．7 MPa;随着热处理温度的提高镀层硬度先稍有下降而后持续提高,到400℃附近达到最大值825HV0．1／20,随后开始 下降;低于200℃的低温退火处理过程中,镀层的腐蚀电位Ecorr有所提高,高于200℃的退火过程中,腐蚀电位Ecorr和腐蚀电 流整体有下降的趋势。

Effect of heat treatment temperatures on characteristic of electroless Ni-P alloy deposits on AZ91D

Adhesion resistance, hardness and polarization properties of electroless Ni-P coating were studied at various heat treatments, the coating were deposited on AZ91D magnesium alloy. The adhesion resistances, the hardness and the polarization properties were measured by F106 adhesion ergometer, HVS-1000 micro hardness tester and PS-16A electrochemistry analysis system respectively. The results showed that phosphorus content of electroless coating was 6.68%wt, and the films' adhesion resistance was good. With anneal temperatures increasing from 200 ℃ to 450 ℃, adhesion resistance failed firstly and then heightened quickly, when the temperature reached 350 ℃,the maximal adhesion resistance 3.7 MPa was obtained. The hardness showed a little fall and then increased, the maximum 825HV0.1/20 was obtained when the anneal temperature reached 400 ℃. The coatings' Ecorr increased when the anneal temperature was lower than 200 ℃, however, when it was over 200 ℃, the Ecorr and the corrision tended to fall.