预电离大气压低温等离子体射流及其在表面清洗中的应用

具有高化学活性的大气压放电低温等离子体射流具有潜在的应用价值。为此,介绍了一种利用预电离办法产生Ar/O2等离子体大气压低温射流及其在表面油污清洗中的应用。采用针电极放电等离子体作为预电离源,为射流介质阻挡放电(DBD)提供种子电子,使得射流DBD的击穿与维持电压得以降低,即使在氧气与氩气体积比高达6%时,也可以产生均匀稳定的放电模式。采用光纤温度传感器检测得到放电等离子体气体温度在390～440K,而Boltzmann斜率法计算得到的电子激发温度为4640K,通过示踪元素法计算得到氧原子数密度在1017 cm-3量级。将该射流应用到玻璃表面油污清洗,最大清洗速率可达0.1mm/s。所以预电离技术可以产生具有高化学活性的均匀放电的大气压低温等离子体射流,该射流在表面油污清洗中具有较高效率。

Atmospheric Pressure Low Temperature Plasma Jet Assisted by the Preionization and Its Application on Surface Cleaning

We investigated an atmospheric pressure nonequilibrium argon/oxygen plasma jet generated in O2/Ar mixtures by specially designed equipment with two coaxial quartz capillaries and double power electrodes,and presented its application in oil removal from material surface.By taking the syringe needle plasma as its pre-ionization source to supply seed electrons for the hybrid barrier-jet discharge,uniform discharge mode with a lower breakdown voltage even when the ratio of oxygen in argon was up to 6% could be generated.The Boltzmann’s plot was performed by time-averaged optical emission spectroscopy to evaluate the excitation electron temperature,showing that the value is 2678 K,meanwhile,the gas temperature was from 390 K to 440 K measured by a fiber thermometer.The concentration of atomic oxygen was estimated by actinometry to be about in an order of magnitude of 1017 cm-3.The jet was then employed to oil removal from glass surfaces and a maximum cleaning rate of 0.1 mm/s was achieved.Results show that the preionization technology is an effective method to generate atmospheric pressure uniform discharge plasma jet with high plasma chemistry activity,and the jet can be applied to oil removal from material surface effectively.