Since the formation of fouling reduces heat transfer efficiency and causes energy loss, anti-fouling is desirable and may be achieved by coating. In this work, a nickel-tungsten-phosphorus (Ni-W-P) coating was prepared on the mild steel (1015) substrate using electroless plating by varying sodium tungstate concentration to improve its anti-fouling property. Surface morphology, microstructure, fouling behavior, and heat transfer performance of coatings were further reported. Also, the reaction path, transition state, and energy gradient change of calcite, aragonite, and vaterite were also calculated. During the deposition process, as the W and P elements were solids dissolved in the Ni crystal cell, the content of Ni element was obviously higher than that of the other two elements. Globular morphology was evenly covered on the surface. Consequently, the thermal conductivity of ternary Ni-W-P coating decreases from 8.48 W/m·K to 8.19 W/m·K with the increase of W content. Additionally, it goes up to 8.93 W/m·K with the increase of heat source temperature 343 K. Oxidation products are always accompanied by deposits of calcite-phase CaCO₃ fouling. Due to the low surface energy of Ni-W-P coating, Ca²⁺ and [CO₃]²⁻ are prone to cross the transition state with a low energy barrier of 0.10 eV, resulting in the more formation of aragonite-phase CaCO₃ fouling on ternary Ni-W-P coating. Nevertheless, because of the interaction of high surface energy and oxidation products on the bare matrix or Ni-W-P coating with superior W content, free Ca²⁺ and [CO₃]²⁻ can be easy to nucleate into calcite. As time goes on, the heat transfer efficiency of material with Ni-W-P coating is superior to the bare surface.

中文翻译：

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Ni-WP三元涂层的传热性能及防污机理研究

由于结垢的形成降低了传热效率并导致能量损失，因此期望结垢并且可以通过涂覆来实现。在这项工作中，通过改变钨酸钠的浓度，使用化学镀法在低碳钢（1015）基材上制备了镍钨磷（Ni-WP）涂层，以提高其防污性能。进一步报道了涂层的表面形态，微观结构，结垢行为和传热性能。此外，还计算了方解石，文石和球ate石的反应路径，过渡态和能级变化。在沉积过程中，由于W和P元素固溶在Ni晶胞中，因此Ni元素的含量明显高于其他两种元素。球状形态均匀地覆盖在表面上。所以，随着W含量的增加，三元Ni-WP涂层的热导率从8.48 W / m·K降低到8.19 W / m·K。此外，随着热源温度343 K的增加，它上升到8.93 W / m·K。氧化产物总是伴随着方解石相CaCO的沉积₃结垢。由于Ni-WP涂层的表面能低，Ca ²⁺和[CO ₃ ] ²⁻易于以0.10 eV的低能垒穿过过渡态，导致文石相CaCO ₃结垢的形成更多在三元Ni-WP涂层上。然而，由于高表面能和氧化产物在裸露的基体或具有较高W含量的Ni-WP涂层上的相互作用，游离的Ca ²⁺和[CO ₃ ] ²⁻易于成核为方解石。随着时间的流逝，具有Ni-WP涂层的材料的传热效率优于裸露表面。