纳米SiO_2微粒的质量浓度对Ni-Zn-P/纳米SiO_2复合镀层组织和性能的影响

Effect of Mass Concentration of Nano-SiO_2 Particle on Microstructure and Properties of Ni-Zn-P/nano-SiO_2 Composite Coating

采用碱式化学镀方法在Q235钢表面制备了Ni-Zn-P合金镀层和Ni-Zn-P/纳米SiO_2复合镀层。研究了硫酸锌、硫酸铵及柠檬酸钠的质量浓度对Ni-Zn-P合金镀层组织的影响,并研究了纳米SiO_2微粒的质量浓度对Ni-Zn-P/纳米SiO_2复合镀层性能的影响。通过单因素试验确定的化学镀Ni-Zn-P合金镀层的最优工艺条件为:硫酸锌0.5g/L,硫酸铵40g/L,柠檬酸钠50g/L,硫酸镍27g/L,次磷酸钠16g/L,pH值9.0,温度85℃。当纳米SiO_2微粒的质量浓度为1.0g/L时,NiZn-P/纳米SiO_2复合镀层表面光滑平整,组织均匀致密。随着纳米SiO_2微粒的质量浓度的增加,Ni-Zn-P/纳米SiO_2复合镀层的硬度逐渐提高。Ni-Zn-P/纳米SiO_2复合镀层比Ni-Zn-P合金镀层更耐Cl-和碱性溶液腐蚀,而且在纳米SiO_2微粒的质量浓度为1.0g/L时,Ni-Zn-P/纳米SiO_2复合镀层的腐蚀速率最低。

Ni -Zn -P alloy coating and Ni -Zn- P/nano SiO2 composite coating were prepared on the surface of Q235 steel by alkaline electroless plating. The effects of mass concentration of zinc sulfate, ammonium sulfate and sodium citrate on the microstructure of Ni- Zn- P alloy coating were studied, and the effect of mass concentration of nano SiO2 particle on the properties of Ni- Zn- P/ nano SiO2 composite coating was also studied. The optimal process conditions of electroless plating Ni- Zn -P alloy coating determined through single factor experiment were as follows： zinc sulfate 0.5 g/L, ammonium sulfate 40 g/L, sodium citrate 50 g/L, nickel sulfate 27 g/L, sodium hypophosphite 16 g/L, pH value 9.0, temperature 85 ℃. When the mass concentration of nano SiO2 particle was 1. 0 g/L, the Ni Zn P/nano SiO2 composite coating features smoothness, compact microstructure. The hardness of Ni- Zn- P/nano SiO2 composite coating increased gradually with the increase of mass concentration of nano SiO2 particle. Furthermore, Ni- Zn -P/ nano SiO2 composite coating has superior corrosion resistance in saline solution containing Cl and alkaline solution compared with Ni -Zn- P alloy coating. When the mass concentration of nano SiO2 particle was 1.0 g/L, the corrosion rate of Ni -Zn- P/nano SiO2 composite coating was the lowest.