摘要
研究了在ZL101铝合金表面化学镀Ni-P合金层的结构、显微硬度和耐蚀性。化学沉积Ni-P合金层的主盐是硫酸镍,次亚磷酸钠为还原剂,柠檬酸钠为络合剂。测试了电解液中光亮剂含量对镀层晶体结构、显微硬度和耐蚀性的影响。XRD衍射图谱显示,在所有镀态下Ni-P合金层均为非晶结构,而经过一定温度的热处理后逐渐向晶态转变直至完全晶化。合金镀层的显微硬度值镀态时较低,约为436 HV,随着热处理温度的升高,在400℃完全晶化后镀层表面的显微硬度值达到最大,约为1 096 HV。在3.5 wt.%NaCl溶液中测定的动电位极化曲线显示,在铝合金表面化学镀Ni-P合金层具有较好的耐蚀性能。
The present work aims to study the structures, microhardness and corrosion resistance of electroless deposit Ni-P coatings on ZL101 aluminum alloy. The main salt of electroless Ni-P coatings is nickel sulfate, sodium hypophosphite acts as a reducing agent and sodium citrate as complexing agent. The influence of brightener content in the deposition bath on crystal structure, microhardness and corrosion resistance of the deposits were examined. XRD patterns reveal that the electroless Ni-P coatings plated at all conditions are identified as amorphous, and the complete phase transformation of crystalization occurs after heat-treatment. The microhardness of the electroless Ni-P coatings （HV436） is low under as-cast condition. However, when the temperature was heated up to 400 ℃, the microhardness of complete crystalization plated reached the maximum value （HV1096）. The potentiodynamic polarization test in a 3.5 wt. % NaCl solution also revealed that the Ni-P coatings exhibited good corrosion resistance property in protecting aluminum alloy.
出处
《铸造技术》
CAS
北大核心
2009年第7期929-932,共4页
Foundry Technology
