摘要
采用光谱在线技术(OES)检测了大气压Ar/NH_3 DBD等离子体中的主要粒子为NH,N,N^+,N_2,Ar,H_α,OH。NH是NH_3分解的产物,激发态Ar~*和NH_3分子的潘宁碰撞生成激发态中性粒子NH(c^1Ⅱ)和NH(A^3Ⅱ)。674.5 nm处N原子谱线表明等离子体中产生了N活性原子,为大气压Ar/NH_3同轴介质阻挡放电等离子体合成ε-Fe_3N磁性颗粒提供了可能。研究了各主要粒子谱线强度随NH_3流量和外加电压峰峰值的变化规律,研究结果表明:NH_3流量相同时,随外加电压峰峰值升高,各粒子谱线强度均逐渐增强;外加电压峰峰值相同时,各谱线强度随NH_3流量增加先增强后减弱。外加电压峰峰值相同时,随NH_3流量增加,N活性原子谱线强度先增强后减弱,NH_3流量为20 mL·min^(-1)时,N活性原子谱线强度最强。NH_3流量相同时,随外加电压峰峰值升高,N活性原子谱线强度逐渐减小,主要是由于大气压Ar/NH_3DBD放电模式由多脉冲大气压辉光放电转变为丝状放电造成。多脉冲大气压辉光放电的微放电通道之间相互重叠,各个微放电之间相互影响,导致随外加电压峰峰值升高各谱线强度的增加速率较快。当外加电压峰峰值从4 600 V升高到6 400 V时,大气压Ar/NH_3 DBD的放电模式由单脉冲APGD转变为二脉冲APGD,属于均匀大气压介质阻挡放电,随外加电压峰峰值升高谱线强度的增加速率较快,利于合成e-Fe_3N磁性颗粒。
An atmosphere-pressure Dielectric Barrier Discharge in Ar/NH3 mixtures between cylinder elec-trodes is studied by Optical Emission Spectroscopy and the main particles of atmosphere-pressure Ar/NH3 DBD plasma are NH,N,N+ ,N2 ,Ar,Hα and OH.NH is decomposition products of NH3 ,and NH(c 1Π) and NH(A 3Π)are two kinds of excited-state neutral particles and produced by penning ionization of Ar* and NH3 .The nitrogen active atom is detected at 674.5 nm which may provide the experimental foundation for the synthesis ofε-Fe3 N ferroparticles by the atmosphere-pressure Ar/NH3 DBD plasma.The intensities of main particles are analyzed at different NH3 flow rate and applied voltage peak-peak value.The results show that the spectral line intensities of various particles increase with the rise of the applied voltage peak-peak value at the same NH3 flow rate,and first increase and then decrease with the increase of the NH3 flow rate at the same applied voltage peak-peak value.The applied voltage peak-peak value being kept constant,the spectral line in-tensity of nitrogen active atom first increases and then decreases with the increase of the NH3 flow rate.When NH3 flow rate is 20 mL·min-1 ,the spectral line intensity of nitrogen active atom reaches a maximum at the same applied voltage peak-peak value.The spectral line intensity of nitrogen active atom decreases gradually with increasing the applied voltage peak-peak value at the same NH3 flow rate and it is mainly because of the translation of discharge mode from multi-pulse APGD to filamentary discharge in the atmosphere-pressure Ar/NH3 DBD.The microdischarge channels overlap and the microdischarges affect each other in multi-pulse APGD;hence the increasing rate of the spectral line intensity is quicker in multi-pulse APGD than in filamen-tary discharge with increasing the applied voltage peak-peak value.When the applied voltage peak-peak value is up from 4 600 to 6 400 V,the single-pulse and two-pulse APGD mode which are two kinds of homogeneous DBD mode are found in the atmosphere-pressure Ar/NH3 DBD and the increasing rate of the spectral line in-tensity is quicker in multi-pulse APGD than in filamentary discharge which is beneficial to synthesize ε-Fe3 N ferroparticles.
出处
《光谱学与光谱分析》
SCIE
EI
CAS
CSCD
北大核心
2015年第3期765-771,共7页
Spectroscopy and Spectral Analysis
基金
The National Natural Science Foundation of China(51077006)
关键词
同轴介质阻挡放电
发射光谱
Ar/NH3
等离子体
Coaxial cylinder dielectric barrier discharge
Optical emission spectroscopy
Ar/NH3 plasma