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采用化学镀的方法,调整化学镀工艺参数中钨酸钠的浓度,在低碳钢(1015)表面获得了钨含量不同的Ni-W-P镀层,分别采用扫描电镜、X射线衍射仪以及MH-6表面硬度计研究了钨含量对Ni-W-P镀层表面形貌、结构以及显微硬度的影响。结果表明,镀液浓度对于获得磷和钨含量起到决定性的作用,而磷和钨的含量决定了Ni-W-P镀层的表面形貌和结构。胞状晶的形成是Ni-W-P镀层的共同特征,镀层中钨含量的增加降低了磷的含量,因此改变了纳米晶相的含量。由于钨固溶于镍中诱使镀层产生固溶强化,限制了镀层局部塑性变形,从而增加了镀层的硬度。采用差热分析研究相变行为的结果表明,高钨含量的Ni-W-P镀层表现为较高的晶化温度。进一步的污垢沉积试验表明,与低碳钢表面相比,含有不同钨含量的Ni-W-P镀层表面抑制了污垢的黏附。进一步研究表明,污垢沉积速度与钨的含量有着直接的联系,而与Ni-W-P镀层表面粗糙度之间没有必然的联系。
The electroless plating method was used to adjust the concentration of sodium tungstate in the electroless plating process parameters. Ni-WP coatings with different tungsten contents were obtained on the surface of mild steel (1015). Scanning electron microscopy, X-ray diffractometry and MH- The effect of tungsten content on the surface morphology, microstructure and microhardness of Ni-WP coating was investigated by surface hardness tester. The results show that the bath concentration plays a decisive role in obtaining the content of phosphorus and tungsten, while the content of phosphorus and tungsten determines the surface morphology and structure of the Ni-W-P coating. The formation of cellular crystals is a common feature of Ni-W-P coatings. The increase of tungsten content in the coatings reduces the content of phosphorus, thus changing the nanocrystalline phase content. Due to the fact that tungsten dissolves in nickel to induce the solid solution strengthening of the coating, it limits the local plastic deformation of the coating and increases the hardness of the coating. The results of phase transition behavior by differential thermal analysis show that Ni-W-P coatings with high tungsten content exhibit higher crystallization temperature. Further soil deposition tests showed that the surface of Ni-W-P coatings containing different tungsten contents inhibited soil adhesion as compared to mild steel surfaces. Further studies have shown that there is a direct relationship between the deposition rate of fouling and the tungsten content, but not necessarily related to the surface roughness of the Ni-W-P coating.