Excimer laser-induced hydrodynamical effects and surface modifications on silicon carbide

被引:10
作者
Nicolas, G
Autric, M
机构
[1] UMR CNRS 138, IRPHE LP3, Parc Sci. et Technologique de Luminy, 13009 Marseille
关键词
D O I
10.1016/0169-4332(95)00433-5
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
The use of lasers in many applications requires an understanding and control of the fundamental processes involved during the laser radiation-material interaction. The importance and the duration of the phenomena involved (optical, thermal, mechanical, electromagnetic, radiative) depend on parameters such as the power density of the laser radiation, the nature and the surface morphology of the material, the surrounding gas and the wavelength of the radiation. A part of the incident energy is reflected by the surface, while the remaining quantity of this energy is absorbed by the material. This incident energy contributes to heating, melting, vaporization and plasma formation if the laser intensity is sufficiently high. The present study is devoted to the ceramic material irradiation in air by an excimer laser at a wavelength of 248 nm and a pulse duration of 20 ns. The objective is to understand the different phenomena induced by radiation and to improve mechanical properties of the surface. Presented results concern the dynamics of plasmas and shock waves, plus surface modifications (porosity, roughness, composition changes) on silicon carbide samples (SiC). A part of the study has resulted in the characterization of the flow created in front of the sample revealing different hydrodynamical regimes. Visualizations of the luminous plasma front and shock waves have been obtained using a fast electronic camera IMACON 790 and a ICCD camera. These optical devices have permitted us to observe simultaneously the formation and expansion of different fronts (plasma and shock waves) propagating into the surrounding gas. The results have been compared to the theory. Complex structures inside the plume have been observed inducing a turbulence phenomena some milliseconds after the irradiation. On the other hand, the surface morphology has been characterized by observations with a scanning electron microscope (SEM) showing important modifications of the morphology according to the energy density and number of pulses applied. A decrease of surface porosity is revealed using image processing technique. This improvement is accompanied with an increase of roughness which has been measured by mechanical profilometry and might be detrimental for friction applications. In addition, an analysis of the material in depth by Auger electron spectroscopy (AES) has shown chemical composition changes (an increase in the percentage of silicon) in the zone irradiated.
引用
收藏
页码:296 / 301
页数:6
相关论文
共 17 条
[1]  
BERGMANN HW, 1994, NATO ADV SCI INST SE, V265, P371
[2]  
BERGMANN HW, 1991, J PHYS-PARIS, V4, P7
[3]   LARGE-SCALE EXCIMER-LASER PRODUCTION OF SUBMICRON PERIODIC STRUCTURES ON POLYMER SURFACES [J].
BOLLE, M ;
LAZARE, S .
APPLIED SURFACE SCIENCE, 1993, 69 (1-4) :31-37
[4]  
DEPOORTER GL, 1990, METALS HDB, V2, P1019
[5]   LASER-INDUCED FLUORESCENCE STUDIES OF EXCIMER LASER ABLATION OF AL2O3 [J].
DREYFUS, RW ;
KELLY, R ;
WALKUP, RE .
APPLIED PHYSICS LETTERS, 1986, 49 (21) :1478-1480
[6]  
GEOHEGAN DB, 1994, NATO ADV SCI INST SE, V265, P165
[7]  
HONTZOPOULOS E, 1990, P SOC PHOTO-OPT INS, V1397, P761
[8]   SILICON AGGREGATES PRODUCED BY LASER-BEAM IN A SILICON-CARBIDE SURFACE [J].
HUONG, PV ;
SEGOND, O ;
GENTILINI, P ;
CAVAGNAT, R .
APPLIED SURFACE SCIENCE, 1989, 43 :256-259
[9]   EXCIMER-LASER SURFACE PROCESSING OF CERAMICS - PROCESS AND PROPERTIES [J].
JERVIS, TR ;
NASTASI, M ;
HUBBARD, KM ;
HIRVONEN, JP .
JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 1993, 76 (02) :350-355
[10]  
LUKYANCHUK BS, 1993, LECT NATO ASI