Preparation Of Nanometer Structures And Their Properties By Microsphere-assisted Laser Direct Writing

This work proposes a new idea of silica microspheres in the liquid phase as a focusing lens to assist laser direct writing.On the surface of iron-nickel alloys and titanium alloys,micro-nano structures smaller than the conventional laser direct writing process size are fabricated.The Scanning electron microscopy(SEM)and contact angle measuring instrument have studied the influence of laser power,microsphere size and concentration on its surface morphology and contact angle.The background,development status and basic theory of microsphere-assisted laser processing and micro/nano structure characteristics are mainly studied,including the mechanism of laser-substance interaction,microsphere-assisted laser processing mechanism,and microsphere-assisted laser processing mechanism in liquid phase.Provide research background and basic theory.This thesis introduces the microsphere-assisted laser processing technology in liquid phase and the experimental results test and analysis equipment,and designs the experimental system.In the liquid phase,microspheres assisted laser processing of iron-nickel alloys.Different sizes of silica microspheres and different concentrations of microsphere solutions were selected.The parameters such as laser power,number of laser scans,laser scanning interval,and laser scanning speed were tested.A pit-like structure was machined on the surface of the alloy,which verified the feasibility of this method.SEM was used to characterize the structure,and the effects of laser parameters on the surface micro-nano structure,the effect of microsphere solution concentration on the surface micro-nano structure,and the effect of microsphere size on the surface micro-nano structure.Its wetting characteristics were also analyzed in detail.The analysis showed that the laser fluence determined the shape of the structure.With the increase of the laser fluence,the size of the pit structure increases.At the same time,the concentration of the microspheres determined the number of pit structures.The size of the pits depended on the size of the microspheres.A variety of the structures were fabricated on iron-nickel alloys by microsphere-assisted laser processing in the liquid phase,and the influence trend of various parameter conditions on the structure was found.Microsphere-assisted laser processing of titanium alloys in the liquid phase,according to the rules obtained when processing iron-nickel alloys,when processing titanium alloys,focus on the influence of laser power,laser scanning distance and microsphere size on micro-nano structure and wettability.The conclusions were given as the following:(1)With the increase of the laser fluence,the size and depth of the microscopic pit-shaped structure generated on the titanium alloy tend to increase.In addition,the number of nanopores tends to decrease,and the corrugated structure also tends to deepen.The contact angle of the structure also tends to increase.(2)When the laser scanning interval is large,there are basically only pit-shaped structures.When the scanning interval is small,there are both pit-shaped structures and corrugated structures.As the scanning interval decreases,the number of pit-shaped structures increases.The contact angle of the structure is affected by the size and number of pit-shaped structures and the presence or absence of corrugated structures.(3)As the size of the microsphere increases,the pit-shaped structure increases,the larger the pit-shaped structure,the greater the contact angle of the structure.According to the conclusions drawn,changing the parameters can prepare the micro-nano structure of the titanium alloy surface with the required specific wettability.This experiment may provide new research ideas on the design of hydrophilic and hydrophobic structures on the surface of titanium alloys and the conversion of hydrophilic and hydrophobic structures.The processing is carried out under liquid phase conditions,and the solution can be reused without time-consuming configuration.The microspheres are limited to the solution and will not splash into the air,reducing the possibility of inhaling silica particles in the experiment.It has very broadly potential value and significance in scientific research and production in future.