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| 摘要: |
| 通过探讨WC颗粒对扁平粒子厚度及喷涂后WC颗粒尺寸变化的影响，研究了超音速火焰喷涂过程中WC－Co深层的沉积过程。使用具有不同WC尺寸的四种WC-Co粉末，采用JET－KOTE喷枪系统喷制了WC－Co涂层。结果发现涂层中WC颗粒的大小主要取决于原始粉末中WC的尺寸．在粉末穿越火焰的过程中，大多数WC处于固态；WC-Co涂层的沉积涉及固液两相离子的扁平化，而不是象在优化条件下金属或陶瓷材料喷涂过程中仅存在单一液相的情况。很明显WC-Co粉末中的WC的大小对涂层的形成影响很大、在超音速火焰喷涂条件下当液固粒子碰撞到已形成的涂层表面上时，其中的大颗粒WC粒子容易被反弹脱落。基于实验结果，提出了计算由液相聚积固相形成的波固两相颗粒碰撞到表面时形成扁平粒子的厚度的模型。 |
| 关键词: 热喷涂,超音速火焰喷涂,WC-Co,液固两相粒子,涂层形成 |
| DOI： |
| 分类号:TQ639 |
| 基金项目: |
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| Effect of WC Particle Size on the Formation of HVOF Sprayed WC-Co Coatings |
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Changjiu Li
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| Abstract: |
| Deposition process of WC-Co coatings in HOVF spraying process is examined by investigating the effect of WC particle size on the thickness of flattened particles and the change of the carbide sizc after spraying.WC-Co coatings are sprayed by JET-KOTE process using four types of powders of different carbide size. It has been found that the size of WC Particles in a sprayed coating depends greatly on the size of those in starting powder. The results show that the most WC particles remain at solid state after passing through the flame and the deposition of a WC -Co coating involves flattening of solid-liquid two phase droplet rather than single liquid drolet as in spraying of metallic and ceramic materials under optimized conditions. It is clear that the size of WC particles in WC-Co powder influences greatly the formation of a WC-Co coating. It is evident that the larger WC particles in a two phase droplet tend to rebound off casily under HVOF spraying conditions When the droplet impacts on the surface of formed coaing. A model is proposed to estimate the thickness of flattened particles when a two phase droplet with liquid glomerated solid particles impacts on a surface. |
| Key words: Thermal spraying WC-Co Solid-liquid two phase droplet coating formation |
