热喷涂参数对喷涂WC-Co合金表面温度的影响

目的建立在线检测系统，控制在高速氧气燃料（HVOF）热喷涂加工过程中加工参数．以获得最佳机械性能的硬质合金（WC-Co）涂层．方法采用热喷涂加工方法把金属．金属陶瓷和陶瓷材料以熔融状态和半熔状态沉积在各种预先处理的基体上．通过使用HVOF喷涂加工技术生产WC-Co合金表面涂层，采用红外线温度测量仪对不同参数加工表面涂层的温度进行了测量．基于热量传递理论和物理量纲分析方法建立了涂层表面温度和加工参数之间的理论公式．结果涂层表面温度与热功率成正比而与喷枪的移动速度和靶距成反比．靶距对涂层表面温度的影响要比速度对涂层件表面温度的影响大，转动角度对涂层表面温度有一定的影响．结论用温度作为中间变量来控制加工参数．采用一定的表面温度测量方法，提取信号并控制主要参数，从而实现工艺参数-表面温度-加工质量闭环系统控制，以达到最佳表面质量．

Analysis of Thermal Load and Surface Temperature in the Production of Thermally Sprayed WC-Co Coatings

A system for the on-line measurement and evaluation of the temperature distribution on coating surface was integrated in the production process of thermal spray in order to determine suitable parameters and by controlling the thermal load during the HVOF process,optimized mechanical properties of WC-Co coatings can be achieved.By using the thermal spraying processes,metallic,cermets and ceramic materials are deposited in a molten or semi-molten state on a previously prepared substrate.Thermally sprayed WC-Co coatings produced by using the HVOF(High Velocity Oxygen Fuel) technology can be used to improve the wear behaviour of metallic substrates.The temperature under different thermal spraying parameters is meassuring with the help of infrared thermalgraphy.A theosetical formula between different process parameters and surface temperature is set up based on energy transfer principle and physic dimensions analysis.Theoretical analysis shows that temperature on coating surface is directly proportional to thermal power and inversely proportional to velocity and distance of spray gun.The distance of spray has greater influence on temperature on coating than velocity and angle of spray gun have.The experimental data are consistent with theoretical analysis.Therefore,temperature on coating is taken as intermediate variable to control processing parameters and is measured by some methods to control main parameters as a signal.A closed loop system among parameters and temperature as well as quality is set up to obtain optimized mechanical properties of coatings.