FIB-SEM Sectioning Study of Decarburization Products in the Microstructure of HVOF-Sprayed WC-Co Coatings
FIB-SEM Sectioning Study of Decarburization Products in the Microstructure of HVOF-Sprayed WC-Co Coatings
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DOI：
10.1007/s11666-018-0721-3
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发表时间：
2018-05
影响因子：
3.1
通讯作者：
Vasileios Katranidis;S. Gu;D. Cox;M. Whiting;S. Kamnis
中科院分区：
文献类型：
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作者：
Vasileios Katranidis;S. Gu;D. Cox;M. Whiting;S. Kamnis
wc基粉末在各种喷涂过程中的热溶解和脱碳是一个被广泛研究的现象，并提出了描述其发展的机制。然而，金属W等脱碳产物的确切形成机制尚未确定。WC-17Co涂层故意以超长的喷涂距离喷涂，以夸大脱碳效果。渐进式氙等离子体离子铣削被检查的表面揭示了微观结构特征，这些特征会被传统的抛光抹掉。系列切片提供了对脱碳产品的三维结构的见解。已经发现金属W在小碎片周围形成一个壳，这些碎片在撞击时没有明显变形，这表明它的结晶发生在颗粒的飞行阶段。W2C晶体在靠近薄片边界的WC表面上更为突出，表明这些位置的脱碳速度加快。孔隙度可以通过其形状清楚地划分为不完全片间接触和氧化生成气体。
The thermal dissolution and decarburization of WC-based powders that occur in various spray processes are a widely studied phenomenon, and mechanisms that describe its development have been proposed. However, the exact formation mechanism of decarburization products such as metallic W is not yet established. A WC-17Co coating is sprayed intentionally at an exceedingly long spray distance to exaggerate the decarburization effects. Progressive xenon plasma ion milling of the examined surface has revealed microstructural features that would have been smeared away by conventional polishing. Serial sectioning provided insights on the three-dimensional structure of the decarburization products. Metallic W has been found to form a shell around small splats that did not deform significantly upon impact, suggesting that its crystallization occurs during the in-flight stage of the particles. W2C crystals are more prominent on WC faces that are in close proximity with splat boundaries indicating an accelerated decarburization in such sites. Porosity can be clearly categorized in imperfect intersplat contact and oxidation-generated gases via its shape.