喷枪空间行进速率对等离子喷涂Mo/8YSZ复合涂层温度场的影响

为了突破传统金属/陶瓷双层热防护涂层高温环境易剥离的技术瓶颈,研究喷枪空间行进速率变化对等离子喷涂Mo/8YSZ复合涂层时间域及空间域温度场分布的影响规律。利用ANSYS有限元分析软件,建立等离子喷涂Mo/8YSZ功能梯度热障涂层的数值模型,考虑材料不同温度下的热物性参数和材料的相变潜热,通过分析不同喷枪空间行进速率下喷涂构件的温度与温度梯度发现:在喷涂过程的同一时刻,喷枪行进速率越大,单位长度内喷枪与构件相互作用的时间越少,构件的最大温度值越小,构件上表面温度分布的均匀性越高,构件的最大温度梯度值越小;先沉积的涂层对后沉积的涂层存在预热作用,基体的最大温度值呈"台阶式"升高的变化趋势;随着涂层厚度的增加,涂层的热阻增加,基体温度的波动幅度逐渐减小;通过调控各涂层的喷枪行进速率,可进一步减小构件的温度梯度,按照黏结层最大、过渡层次之、陶瓷层最小的顺序进行喷涂时,喷涂构件的温度梯度最小。

Effect of space travel velocity of spray gun on temperature field of Mo/8YSZ composite coating prepared by plasma spraying process

In order to break through the technical bottleneck of traditional metal-ceramic double-layer thermal protective coating which is easy to peel in high temperature environment, the influence of the space travel velocity of the spray gun on temperature field in time domain and space domain of the Mo/8 YSZ composite coating was studied. Using ANSYS finite element analysis software, a numerical model for preparing Mo/8 YSZ functionally graded thermal barrier coatings by plasma spraying was established, and the thermal properties of the material at different temperatures and the latent heat of phase change of the material were also considered in the model. By analyzing the temperature and temperature gradient of the sprayed component under the different space travel velocities of the spray gun, it is found that at the same time of the spraying process, the greater the travel velocity of the spray gun,the less time the spray gun interacts with the component per unit length, the smaller the maximum temperature value of the component, the higher the uniformity of the temperature distribution on the upper surface of the component, and the smaller the maximum temperature gradient value of the component. The first deposited coating has a preheating effect on the post-deposited coating, and the maximum temperature value of the substrate exhibits a "stepped" increase trend. As the thickness of the coating increases, the thermal resistance of the coating increases, and the fluctuation of the substrate temperature gradually decreases. The temperature gradient of the component can be further reduced by adjusting the travel velocity of the spray gun of each coating, and the temperature gradient of the component can be minimized when the spraying is undertaken in accordance with the sequence of maximum bonding layer, transition layer and minimum ceramic layer.