Interaction Between Laser And Materials Under Different Environmental Conditions

The application of laser is getting wider with the development of laser technology.The important basis of laser application is the interaction between laser and materials.Besides the laser parameters and the properties of the materials,the environmental conditions are also one of the important factors that can affect the interaction between laser and materials.Therefore,this paper designed three experiments to study the influences of the environmental conditio ns on the interaction between laser and materials.Black titanium dioxide shows better absorption performance to the visible light,which provides an alternative to improve the photocatalytic efficiency of titanium dioxide.Also,it was reported that high pressure was the reason for the formation of black titanium dioxide by laser method.In this paper,the titanium dioxide was modified by laser in vacuum and the black titanium dioxide was successfully prepared.Then the phase,morphology,optical absorptio n and photocatalytic properties were analyzed.The results showed that the high pressure was not the necessary condition for the preparation of black titanium dioxide by laser.Both the existence of Ti³⁺?or oxygen vacancies?and the lattice disorder struc ture led to the decrease of the band gap of TiO₂,which can greatly enhance the absorption of visible light.However,the recombination efficiency of electrons and holes increased due to the oxygen defects in the bulk,which led to the decrease of the photocatalytic performance.It is not conducive to the modification of hafnium and the formation of hafnium compounds due to the high melting point of hafnium.Based on the characteristic of the high temperature plasma plasma generated by the interaction between laser and materials,we designed the experiments of laser ablation of hafnium under four different environmental conditions including deionized water,vacuum,air and air plasma and the phase,morphology of the targets after ablation were analyzed.The results showed that the four different environmental conditions had little effect on the phase change except the oxidation of air and air plasma on hafnium.However,different ablation morphologies of hafnium were formed under different environmental conditions.They were cavities and metal nanoparticles in deionized water,conical ablation pits and periodic corrugated structures in vacuum,blocky and cottony structures in air,holes and cottony structures in air plasma.The influence of laser parameters and ambient temperature on the laser ablation of Zr₅₀Cu₃₅Al₇Pd₅Nb₃ amorphous alloy was studied.The results showed that the crystallization tendency of amorphous alloy appeared after the laser treatment of amorphous alloy at room temperature and with the increasing of laser voltage,laser frequency and irradiation time,the ablation of amorphous alloy become serious.The quenching degree was aggravated because of the low temperature environment,which was not favorable to the crystallization of amorphous alloy.Also,the low temperature environment reduced the high temperature produced by the laser ablation of amorphous al oy,which made the ablation degree decreased.