低温爆炸喷涂WC涂层的理论与试验研究

Theoretical and experimental study on preparing WC coating vialow-temperature detonation spraying

摘要:

为解决爆炸喷涂过程中WC颗粒由于高温导致的脱碳问题,本文设计了一种带有拉瓦尔喷管的爆炸喷涂装置,利用该装置进行了爆炸喷涂WC涂层的理论和试验研究。基于等熵流的数值计算结果表明,喷管可以有效降低载气的温度,并可将WC颗粒加速至1000m/s以上。利用压力传感器测试了喷管入口和出口处的压力,计算了气流马赫数。在喷管出口处采用激光遮挡法测试了粒子的速度,测试结果与理论计算结果具有较好的一致性。采用扫描电镜、金相显微镜和XRD对碳化钨颗粒、涂层进行了表征,结果表明喷管的使用可以有效避免脱碳现象。该研究为解决爆炸喷涂碳化钨过程中的脱碳问题提供了一种新思路。

Abstract:

In order to solve the decarburization problems of WC particles caused by high temperature during detonation spray process, a detonation spraying facility with Laval nozzle was designed. Theoretical and experimental studies on preparing WC coatings via detonation spraying were carried out by introducing that facility. Numerical calculation results based on isentropic flow indicated that the temperature of the carrying gas could be decreased greatly by introducing nozzle, meanwhile, the velocity of the WC particles could also be accelerated up to above 1000m/s. Some pressure sensors were used to test the pressure in the entrance and the exit of the nozzle, the Mach number of the gas was calculated. Laser Extinguish method was employed in the nozzle exit to measure the average velocity of the particles. Both theoretical and experiment results could match each other properly. SEM, metalloscope and XRD were used to characterize WC particles and the coatings. The test results presented that the Laval nozzle could avoid decarburization phenomenon of WC particles effectively. This paper provides a new thought to solve the decarburization problems of WC particles during detonation spraying process.