等离子熔射过程中热传递特性研究  

Heat transfer characteristics of plasma spraying

作　　者：夏卫生[1,2] 张海鸥[2] 王桂兰[1] 

机构地区：[1]华中科技大学材料成形与模具技术国家重点实验室 [2]华中科技大学数字制造装备与技术国家重点实验室,湖北武汉430074

出　　处：《华中科技大学学报（自然科学版）》2010年第3期1-3,24,共4页Journal of Huazhong University of Science and Technology(Natural Science Edition)

基　　金：国家高技术研究发展计划资助项目(2007AA04Z142);国家自然科学基金资助项目(50675081);中国博士后科学基金资助项目(20080440940)

摘　　要：采用红外测温仪检测单位时间内基体温度变化来衡量射流与粒子流(含粉末粒子的射流)的加热效应,实验研究了等离子弧电流、电压、熔射距离以及送粉速率变化对加热效应的影响规律,进而对比分析射流和粒子流与基体/已熔射涂层之间的热传递特性.实验结果表明:等离子熔射过程中的加热效应主要取决于射流引起的对流传热;粒子流的加热效应特点与射流不同,而粉末粒子仅对其沉积区域的温升有贡献;随着熔射距离的增加,射流的加热效应急速下降;等离子弧电流和电压的增大相应地提升了喷枪功率,加大了射流与基体间的对流传热.The temperature changes in the unit time were detected by infrared pyrometers to quantify the heating effects of plasma jet and particle flux （with powder feeding）.The influences of the heating effects were experimentally studied under the spraying conditions with different plasma arc voltage and current,spray distance and powder feeding rate.On these results,the heat transfer characteristics between plasma jet and particle flux and substrates/sprayed coatings were compared and analyzed.Experimental results show that the heating effect is mainly dominated by the convection heat transfer of plasma jet during plasma spraying.The heat transfer characteristic of particle flux is different with that of plasma jet and spraying particles are only contributed to the temperature rise of the deposited zone.The heating effect of plasma jet drops rapidly with the increase of spraying distance.Increase in plasma current and voltage increases the power of plasma gun,and thus enhance the convection heat transfer of plasma jet.

关 键 词：等离子熔射 热传递 等离子射流 粒子流 加热效应 工艺参数 

分 类 号：TG174.442[金属学及工艺—金属表面处理]