Plasma Diagnosis And Irradiation Modification Of TiAl Alloy

Low-temperature plasma is a science and engineering that has a significant impact on the development of science and technology and industrial applications nowadays.In the future,the integration and miniaturization requirements of the semiconductor industry will be higher,so there is an urgent need for further development of low-temperature plasma processing technology to improve the precision of interaction with materials,to better adjust the plasma ion energy,incident angle and the scope of materials,etc.This study successfully built a set of radio frequency?rf?plasma diagnostic system and plasma modified equipment.Various radio frequency?rf?plasmas such as Ar,N₂,N/D gas mixture,and CH₄ were diagnosed by mass spectrometry.The main composition and energy distribution of plasma ions were measured and analyzed.Certain rules and adjustment methods were summarized.Finally,guided by the plasma diagnostic data,the modification of TiAl alloy was carried out by CH₄ plasma,and the modification process was initially explored.The author found that methane plasma has a positive effect on the oxidation resistance of TiAl alloy at high temperature.The results show that:?1?The ion energy distribution of Ar,N₂ and other different rf plasmas moves towards the lower energy end as the intake rate increases,including the peak energy and the maximum energy.This is due to the fact that higher gas velocity leads to higher pressure which leads to an increase in the frequency of elastic and inelastic collisions between particles.?2?When external antenna is used,the energy distribution of Ar⁺and N₂⁺ions is usually single-peak structure,while other composite ions are mostly multi-peak structure.When internal antenna is used,the Ar⁺ion energy distribution has a bimodal structure.The different distribution structure of the ion energy distribution is due to the combined effect of radio frequency modulation of the plasma sheath voltage and ion-neutral molecular charge exchange.?3?There are several ways to adjust the ion energy of rf plasma in addition to the gas intake.One is to adjust the incident power of rf power supply.The second is to adjust the distance between the plasma discharge coil and the plasma.The third is to adjust the structure of the plasma discharge coil.The internal type produces plasma ion energy one order of magnitude higher than the external type antenna.?4?Methane plasma plays a positive role in improving the antioxidation performance of TiAl alloy,and the ion flux density and ion energy of methane plasma have a key effect on the modification effect,so the selection of appropriate plasma parameters is conducive to the improvement of the modification effect.