| Laser micro/nanostructureing technology has potential application and great research value in the field of material surface functionalization.With the development and progress of science and technology,nanosecond laser,as a lowcost,high-efficiency,easy-to-maintain,and green manufacturing method,has been widely used in industrial and scientific research fields.Nanosecond laser micro/nano manufacturing can realize the personalized design,high-efficiency processing and controllable preparation of functional surfaces.Ni Ti alloy is one of the most promising titanium-based materials.In order to expand the application of Ni Ti alloys,it is of great research significance and application value to apply laser micro/nano structured technology to the surface of Ni Ti alloys for achieveing shape control and multifunctionality of micro/nanostructures.The research on the micro/nano structure of Ni Ti alloy surface prepared by nanosecond laser was carried out in this paper,which has certain guiding significance for the development of controllable function surface of Ni Ti alloy.1.This paper adopts three methods of linear scanning,circular scanning and composite scanning to process Ni Ti alloy.Based on the linear scanning method,the influence of process parameters on the surface morphology was analyzed: the roughness and the depth of the groove decrease with the increase of the scanning speed,and increase with the increase of the laser pulse frequency.These results provide the basis for shape control of the alloy surface.The circular scanning and composite scanning processing methods were designed,and three novel surface micro/nanostructures were prepared,including Donut-like structure,Hotdog-like structure and Banana-like structure.Then,we systematically characterized and studied the surface morphology,element composition,and roughness of these three structures.And combined nanosecond laser and material interaction mechanism,we comprehensively discussed the type,formation,and evolution of surface micro/nanostructures.2.Based on these three micro / nano structures,water contact angle tests and electrochemical corrosion studies on their surfaces were performed.The water contact angle test results show that: BLS(hydrophobic)> HLS(hydrophobic)> PS(hydrophilic)> DLS(hydrophilic).The electrochemical corrosion test shows that DLS has the best corrosion resistance and reveals its interface corrosion behavior(oxide film-remelt layer-substrate).It also shows that the functional micro/nano structures prepared by nanosecond laser one-step method also have certain corrosion resistance,which will provide a theoretical basis for the corrosion protection of Ni Ti alloy.3.Cytotoxicity experiments on these three micro / nano structures were performed.After 1 day incubation,the fluorescence microscopy pictures of the cells show that the numbers of adherent cells on the surface of the micro / nano structure are significantly increased in comparison with the original surface.The results of MTT experiments show that the cells on DLS structure have the highest activity and the best cell compatibility.The cell morphology observation results show that the micro/nano structure can induce cell spreading,provide binding sites for cell/pseudofoot adhesion,promote mechanical interlocking between cells and materials,and then improve the interaction between cells and materials.Based on the comprehensive biocompatibility assessment and electrochemical corrosion behavior analysis,DLS structure surface was prepared for service in the human microenvironment(mainly bone repair).4.Based on the HLS structure,four kinds of light-trapped micro/nano structure preparation schemes are designed: changing the scanning circle angle,changing the scanning speed,changing the scanning circle pitch,and performing multi-layer scanning processing methods.The trapping-light performance results show that compared with the original sample,the four schemes all produce effective light trapping effects.Among them,the light trapping effect,surface roughness,chemical composition,and process parameter changes in schemes 1and 2 exhibit strong regularity,which are beneficial to the shape control of the surface light trapping structure of Ni Ti alloy.The third scheme has the obvious improvement of the light trapping effect.This process is simple,adjustable and controllable,which is beneficial to the efficient preparation of light trapping microstructures.In addition,in all schemes,the 10-scanning in scheme 4possesses the best effect,and the overall reflectance in the 400 ? 800 nm band approaches 5%.The research in this paper can be applied to the fields of biomedicine,corrosion protection and new energy. |
PDF Full Text Request