摘要
目的探究热阴极材料对先进等离子物理气相沉积(PS-PVD)射流的影响。方法分别采用铈钨、钍钨和镧钨材料制备大功率等离子喷枪阴极,在相同工艺条件下制备涂层,采用光学发射光谱仪(OES)检测无送粉和送粉状态下的等离子射流光谱强度,分别评价射流的能量场分布及稳定性,通过扫描电子显微镜对涂层微观形貌进行观察和分析。结果在无送粉状态下,使用镧钨阴极时射流中的ArⅠ和HeⅠ特征峰强度在400~1000 mm之间最高,在1000 mm后显著降低;使用钍钨阴极时,轴向中心ArⅠ特征峰强度逐渐升至1000 mm处,之后缓慢下降,HeⅠ特征峰强度的下降速度较快;使用铈钨阴极时,从600~1200 mm,ArⅠ特征峰强度衰减得最缓慢,HeⅠ特征峰的强度逐渐提高;射流光谱强度波动幅度从大到小的顺序为铈钨、钍钨、镧钨;在送粉状态下,在强度峰值区域,钍钨阴极激发射流中不同元素的光谱强度最高,镧钨和铈钨阴极激发射流光谱强度接近,在射流轴线上方均为铈钨阴极的射流光谱强度最高;在高浓度气相区内,钍钨阴极所制备涂层以高气相比例沉积为主,枝晶生长发达,铈钨和镧钨阴极制备涂层柱间出现了较多的球形冷凝颗粒。结论镧钨阴极产生的射流在轴向400~1000 mm范围内的能量强度最高,射流稳定性最好,但在1000 mm之后存在较大的轴向和径向(HeⅠ)能量衰减,其最优喷涂距离应大于等于1000 mm;钍钨阴极产生的射流在轴向400~1000 mm区域内的能量强度和稳定性低于镧钨阴极,但大于1000 mm射流能量强度衰减的速度较慢;铈钨阴极产生的射流在轴向600~1200 mm之间的能量强度衰减最小,且轴向和径向均表现出宽域的能量和气相分布特征,但射流稳定性不足。
The work aims to explore the effect of hot cathode materials on advanced plasma spraying physical vapor deposition(PS-PVD)jet.Cerium tungsten,thorium tungsten and lanthanum tungsten materials were used to prepare high-power plasma spray torch cathodes,and the coatings were prepared under the same process conditions.The optical emission spectrometer(OES)was used to detect the spectral intensity of plasma jet under the conditions with and without powder feeding.The energy field distribution and stability of plasma jet were evaluated respectively,and the microstructure of the coatings was analyzed by scanning electron microscope.Under the condition of no powder feeding,the intensity of ArⅠand HeⅠcharacteristic peaks in the plasma jet with lanthanum tungsten cathode was the highest between 400 mm and 1000 mm,and decreased significantly after 1000 mm.When thorium tungsten cathode was used,the intensity of ArⅠcharacteristic peak in the axial center gradually increased to 1000 mm,then decreased slowly,and the intensity of HeⅠcharacteristic peak decreased rapidly.When cerium tungsten cathode was used,from 600 mm to 1200 mm,the intensity of ArⅠcharacteristic peak decreased most slowly,and the intensity of HeⅠcharacteristic peak gradually increased.The fluctuation of plasma jet was cerium tungsten>thorium tungsten>lanthanum tungsten.In the powder feeding state,in the peak intensity region,the spectral intensity of different elements in thorium tungsten cathode excited plasma jet was the highest,and the spectral intensity of lanthanum tungsten and cerium tungsten cathode excited plasma jet was close.Above the plasma jet axis,the spectral intensity of cerium tungsten cathode was the highest.In the high concentration gas phase region,the coating prepared by thorium tungsten cathode was mainly deposited in high gas phase ratio,and the dendrite growth was developed.A large number of gas phase condensation nano-particles and a certain amount of droplet condensation spherical particles appeared between the coating columns prepared by cerium tungsten and lanthanum tungsten cathodes.The plasma jet generated by lanthanum tungsten cathode has the highest energy intensity and the best plasma jet stability in the axial range of 400~1000 mm,but there is a large axial and radial(HeⅠ)energy attenuation after 1000 mm.Considering the optimal spraying distance≤1000 mm,when the deposition distance is 1200 mm,there are more spherical condensate particles in the coating deposited by lanthanum tungsten cathode.The energy intensity and stability of the jet generated by the thorium tungsten cathode in the axial 400~1000 mm region are lower than those of the lanthanum tungsten cathode,but the energy intensity of the plasma jet greater than 1000 mm decays slowly.The prepared coating exhibits good gas phase diffusion deposition characteristics at different radial positions of the plasma jet in the three cathodes.The plasma jet generated by the cerium tungsten cathode has the smallest energy intensity attenuation between 600~1200 mm in the axial direction,and a wide range of energy and gas phase distribution characteristics show in both axial and radial directions,but the plasma jet stability is insufficient.
作者
姜在龙
何箐
张雨生
赵乾
JIANG Zailong;HE Qing;ZHANG Yusheng;ZHAO Qian(Chinese Academy of Agricultural Mechanization Sciences Group Co.,Ltd.,Beijing 100083,China;Beijing Jinlunkuntian Special Machine Co.,Ltd.,Beijing 100083,China)
出处
《表面技术》
EI
CAS
CSCD
北大核心
2024年第19期223-231,共9页
Surface Technology
作者简介
通信作者:何箐。
