喷嘴形状对Al_2O_3-3TiO_2粒子扁平化及其涂层性能的影响  

Influence of the Type of Nozzle on Particle Flattening and Coating Microstructure of Al_2O_3-3TiO_2

作　　者：文魁[1,2] 刘敏[1,2] 余志明[1] 邓春明[2] 张梦婷[1,2] 

机构地区：[1]中南大学材料科学与工程学院,长沙410083 [2]广东省工业技术研究院(广州有色金属研究院)新材料研究所,广州510650

出　　处：《中国表面工程》2012年第4期49-55,共7页China Surface Engineering

摘　　要：采用SprayWatch在线监测系统测量了F6大气等离子喷枪在不同喷嘴条件下产生的等离子射流中Al2O3-3TiO2粒子的温度和速度。利用201不锈钢和Q235钢作为基体,分别用来收集粒子和制备涂层。分析了不同喷嘴对飞行粒子温度和速度的影响,并通过扫描电镜(SEM)对扁平粒子的铺展程度和涂层显微组织进行了分析,并对比了涂层的结合强度、显微硬度和磨损失重量的差异。结果表明:在相同的测量位置,圆柱形喷嘴喷出粒子的速度比Laval喷嘴条件下的高出一倍,但是温度比Laval喷嘴条件下略低。圆柱形喷嘴获得的扁平粒子比Laval喷嘴获得的扁平粒子铺展程度要大;圆柱形喷嘴获得的涂层的孔隙率及磨损失重量比Laval喷嘴制备的小,其涂层的结合强度、显微硬度均高于Laval喷嘴制备的涂层。The on-line thermal spray system,SprayWatch 3i,was used to measure the velocity and temperature of in flight particles in the plasma jet,which was generated by F6 atmospheric plasma spraying gun equipped with cylindrical nozzle and Laval nozzle.201 stainless steel substrates and Q235 steel substrates were used to collect particles and prepare coatings.The influence of the type of nozzle on the in flight particles was analyzed,and the flattening degree of splat and the microstructure of coatings were analyzed by scanning electron microscope（SEM）.The microstructure,bond strength,microhardness and loss of weight were also studied.The results show that the velocity of in flight particles using cylindrical nozzle is two times than that of using Laval nozzle.However,the particles temperature is slightly lower under the same spraying distance conditions.The flattening degree of splats that were obtained by cylindrical nozzle is larger than those prepared by Laval nozzle.The pore density and loss of weight of coatings deposited by cylindrical nozzle is lower than those using Laval nozzle.The bond strength and microhardness of coatings prepared by cylindrical nozzle are higher than the latter.

关 键 词：大气等离子喷涂 扁平粒子 圆柱形喷嘴 Laval喷嘴 结合强度 显微硬度 

分 类 号：TG174.442[金属学及工艺—金属表面处理]