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| 摘要: |
| 近年来高速火焰喷涂取得了飞速的发展，尽管热喷涂市场上的多种ＨＶＯＦ系统结构各异，但对系统的性能要求是一致的，即：在有限的热量条件下，使喷涂材料达到习可能高的速度以获得结构致密的涂层，而涂层材料本身不发生相变或氧化。ＨＶＯＦ的现有模式几乎都是以燃烧室或加速喷管内高速焰流的稳定燃烧作为系统设计的理论模型，然而随着ＨＶＯＦ技术的不断发展，我们面临着两个问题迫切有待于解决；（１）颗粒速度倒底能被加速到多大 |
| 关键词: 高速火焰喷涂 燃烧室压力 硬度 孔隙率 |
| DOI： |
| 分类号:TG174.442 |
| 基金项目: |
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| Extending the Limits of HVOF |
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Wang Zhijian Tian Xinli
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| Abstract: |
| Within the last years many developments have taken place in the field of HVOF. The number of different HVOF systems offered on the market is increasing. Nevertheless, all offered systems have a common goal: to accelerate the injected spray material to highest possible velocity values with a limited heat input to achieve dense coating structures without deterioration or oxidation of the coating material. Independent of the fuel used or the design principle (chamber stabilized mode or duct stabilized mode), the question of the technological limits of this spraying technique can be raised. Key questions are: (1) how high can the particle vclocity be increased and (2) what are the effects of such increases on the coating. Using a combustion process as the source for accelerating and heating the spray particles, an increase in the gas seam velocity is directly related to a decrease of the temperature and pressure conditions in the effluent hot gas stream. Both change and particularly minimize the interaction of the hot gases with the injected spray particles, which influences the deposition efficiency, the coating structure, composition and properties. Are there technical or commercial limits? These questuins will be discussed in this paper. Especially, the paper will report the results achieved with a specially designed experimental gun, that creates chamber pressures up to 1000 PSI (70 MPa). Due to this capability, the particle velocities as well as the heat input into the particles can be influenced over a wider range than perviously studied. |
| Key words: HVOF-spraying, Chamber pressure, Hardness, Porosity, Oxide contents, WC-Co, NiCrMoNb |
