化学镀 Ni-Mo-P 合金镀层的组织结构与防垢性能研究

目的采用材料测试方法和防垢实验,研究不同工艺条件下的化学镀Ni-Mo-P合金镀层的组织结构与防垢性能。方法在化学镀Ni-P镀层基底上,添加含有钼酸根离子杂多酸盐,在不同工艺条件下化学沉积Ni-Mo-P合金镀层,研究化学镀Ni-Mo-P合金镀层的表面形貌和组织结构,分析镀液中硼酸含量和钼酸铵含量对镀层沉积速率的影响,观测镀层在结垢实验后的表面形貌并分析结垢速率。通过SEM,XRD和EDS对化学镀Ni-Mo-P合金镀层的表面形貌和组织结构进行检测,研究在酸性镀液中硼酸含量对化学镀Ni-Mo-P工艺条件的影响。采用防垢实验测试化学镀Ni-Mo-P合金镀层的防垢性能。结果在化学镀Ni-Mo-P过程中,钼酸根离子杂多酸盐具有稳定作用。化学镀Ni-Mo-P合金镀层的化学沉积镀液的最佳工艺条件为:Ni SO4·6H_2O 16.5 g/L,Na H_2PO_2·H_2O 20 g/L,钼酸钠0.5~0.8 g/L,硼酸2 g/L,乙酸钠7.5 g/L。化学镀Ni-Mo-P合金镀层的结垢速率明显低于化学镀Ni-P镀层,具有良好的防垢能力,形成了非晶态的镀层。结论采用化学镀Ni-P镀层基底上沉积得到非晶态的Ni-Mo-P合金镀层,硼酸具有调节镀液p H值和络合作用,非晶态的Ni-Mo-P合金镀层平均结垢速率最小值为0.58μm/h,具有良好的阻垢能力。

Structure and Scaling Prevention Properties of Electroless Ni-Mo-P Alloy Coatings

Objective To investigate the structure and scaling prevention properties of electroless Ni-Mo-P alloy coatings pre-pared in different deposition process conditions using the materials testing and scale experiment. Methods Under different process-ing conditions, by adding the heteropolyacid salt containing molybdate ion, the Ni-Mo-P alloy coatings were prepared by chemical deposition on the substrate which was firstly chemically deposited with Ni-P coatings. The surface morphology and structure of the electroless Ni-Mo-P alloy coatings were studied, the effects of the molybdate content and the boric acid content in the plating bath on the coating deposition rate were analyzed, and the surface morphology of the coatings was observed and the scaling rate was ana-lyzed. The surface morphology and structure of the coatings were determined by scanning electron microscope ( SEM) , X-ray dif-fraction analysis ( XRD) and EDS, to study the effect of the content of boric acid in the plating bath on the Ni-Mo-P chemical dep-osition process conditions. The scale laboratory tests were used to measure the scaling performance of the Ni-Mo-P alloy coatings. Results The results indicated that the addition of the heteropolyacid salt containing molybdate ion had stabilizing effect on the Ni-Mo-P chemical deposition. Moreover, the optimal process conditions of Ni-Mo-P chemical deposition were 16. 5 g/L of NiSO4 ·6H2 O, 20 g/L of NaH2 PO2 ·H2 O, 0. 5~0. 8 g/L of sodium molybdate, 2 g/L of boric acid,and 7. 5 g/L of sodium acetate. The scaling rate of the electroless Ni-Mo-P alloy coating was obviously lower than that of the electroless Ni-P coating, showing good scaling pro-tection properties, and amorphous coating was formed. Conclusion To obtained amorphous Ni-Mo-P alloy coating,by using the elec-troless plating deposition on the substrate Ni-P coating, boric acid have the capable of regulating pH and the complexing properties of the bath, amorphous Ni-Mo-P alloy coating minimum average rate of fouling is 0. 58 μm/h, with the better scale capacity.