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我们将最近建立的综合性一维模型用于研究与高速氧燃料气(HVOF)喷涂工艺有关的粉粒行为特性,用喷涂 WC-12%粉末作为研究对象。研究表明,努森(Knudsen)非连续效应可能对气-固热迁移和动能传递过程有极大的影响,根据粉粒在 HVOF 喷涂过程中的实际经历,本研究结果显示,氧-燃料气燃烧焰产生的低温虽然不利于许多具有高熔点的陶瓷粉末的充分熔化,但是,金属和低熔点合金的粉末却能够在氧-燃料气火焰中完全熔化。使用 WC—12%Co 粉末发现,只有粒子尺寸小于45μm的粉末颗粒能够充分地熔化,这正好与根据经验生产的 HVOF涂层的实际情况非常吻合。结果还表明,超音速火焰把粉末粒子加速到非常高的速度,在某些情况下大约为700m/s,如此高的粉粒速度是造成 HVOF 工艺能够形成比等离子喷涂层更加致密而且结合更加良好的涂层的主要原因。
We have recently established a comprehensive one-dimensional model used to study the particle behavior associated with the high velocity oxyfuel (HVOF) spray process, using sprayed WC-12% powder as the research object. The results show that the Knudsen discontinuity may have a great influence on gas-solid heat transfer and kinetic energy transfer. According to the actual experience of the powder during the HVOF spraying, the results of this study show that the oxy-fuel gas combustion Although the low temperature generated by the flame is not conducive to the sufficient melting of many ceramic powders with high melting points, the powders of the metal and the low-melting alloy can be completely melted in the oxy-fuel gas flame. Using WC-12% Co powder, it was found that only the powder particles with a particle size of less than 45 μm could be sufficiently melted, exactly in accordance with the empirically produced HVOF coating. The results also show that the supersonic flame accelerates the powder particles to very high speeds, in some cases about 700 m / s, so high particle velocities result in the HVOF process being able to form denser and more well-bonded plasma sprayed layers The main reason for the coating.