Ph.D. Thesis M. Mendes: Excimer Laser Micromachining of Al2O3-TiC Ceramics.
Study of the Process.
Study of the Process.
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Home >> Lasers >> Ph. D. Thesis M. Mendes: Excimer Laser Micromachining of Al2O3-TiC ceramics. Study of the Process.
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Complete Ph.D. Thesis:
Table of Contents and Chapter 1 - Introduction
Chapter 2 - Introductory concepts
General properties of laser radiation and the interaction of laser radiation with matter are introduced. The
absorption of laser radiation by metals and insulators is discussed, and the general mechanisms of laser
ablation are presented.
Chapter 3 - Experimental methods
An overview of excimer laser technology and the fundamental concepts of micromachining using excimer lasers
are presented. The characterisation techniques used throughout this study are briefly described. Finally, the
properties of the materials studied (Al2O3-TiC, Al2O3 and TiC) are analysed.
Chapter 4 - KrF Nanosecond excimer laser micromachining of Al2O3-TiC ceramics in air
The micromachining of Al2O3-TiC composite ceramics in air using KrF (l=248 nm) nanosecond laser pulses
was studied. The influence of the processing parameters was analysed aiming to optimise the machining
process. Surface topography, surface roughness, ablation rate and surface finish machining quality were
investigated as a function of the following parameters:
- Laser fluence;- Number of pulses;- Laser beam spot size;- Laser beam angle of incidence;- Machining with
static or moving sample.
Chapter 5 - Study of the influence of the working atmosphere on the micromachining of Al2O3-TiC ceramics
The effects of the ambient atmosphere on the ablation of Al2O3-TiC using nanosecond duration KrF (l=248 nm)
laser pulses are studied. The influence of the gas type and pressure on the ablation rate and surface
topography is investigated, and the observed changes are correlated with the ablation plume dynamics. The
mechanisms of formation of particles during ablation are studied.
Chapter 6 - Study of the influence of the excimer laser wavelength on the micromachining of Al2O3-TiC
ceramics
The micromachining of Al2O3-TiC ceramics using nanosecond ArF (l=193 nm) and XeCl (l=308 nm) excimer
lasers was studied. The effects of the laser fluence and number of pulses on the ablation rate and surface
topography were analysed. A comparative study of the ablation of Al2O3-TiC using nanosecond laser pulses at
different wavelengths (193, 248 and 308 nm) was performed.
Chapter 7 - Femtosecond excimer laser micromachining of Al2O3-TiC ceramics. Influence of the laser pulse
duration
The micromachining of Al2O3-TiC ceramics using femtosecond duration laser pulses (l=248 nm) is studied.
The results are compared with those obtained when processing is carried out using nanosecond laser pulses
at the same radiation wavelength, in order to investigate the influence of the laser pulse duration on the ablation
process.
Chapter 8 - Final conclusions and future work
The final conclusions of this study are presented. The versatility of the excimer laser projection technique in the
micromachining of Al2O3-TiC as well as the associated difficulties are summarised. Excimer laser processing
and ion beam etching of Al2O3-TiC are compared. Indications for future work are presented.
Appendix A - Thermal model
The finite-difference thermal model developed to investigate heating/ablation during irradiation with nanosecond
duration laser pulses is presented. This model was used to investigate the heating behaviour of Al2O3, TiC and
Al2O3-TiC by considering the fraction of the individual phases in the composite. It allowed to study the influence
on heating of various material properties, namely the optical absorption coefficient and thermal conductivity.
Appendix B - Dynamics of the ablation plume
The ablation plume dynamics was coupled to the finite difference model, in order to estimate the pressure and
attenuation of radiation in the plume.
_______________________________________________________________________________________
Additional Papers:
M. Mendes, R. Vilar, Debris and Particulates Formation and Deposition in UV Pulsed Laser Ablation of
Al2O3-TiC Ceramics, Proceedings of ICALEO 2000, Volume 90, Laser Microfabrication, A67-76 (2000)
M. Mendes, V. Oliveira, R. Vilar, F. Beinhorn, J. Ihlemann, Excimer Laser Micromachining of Al2O3-TiC
ceramics, Laser Assisted Net Shape Engineering 3, 623-634 (2001)
Table of Contents and Chapter 1 - Introduction
Chapter 2 - Introductory concepts
General properties of laser radiation and the interaction of laser radiation with matter are introduced. The
absorption of laser radiation by metals and insulators is discussed, and the general mechanisms of laser
ablation are presented.
Chapter 3 - Experimental methods
An overview of excimer laser technology and the fundamental concepts of micromachining using excimer lasers
are presented. The characterisation techniques used throughout this study are briefly described. Finally, the
properties of the materials studied (Al2O3-TiC, Al2O3 and TiC) are analysed.
Chapter 4 - KrF Nanosecond excimer laser micromachining of Al2O3-TiC ceramics in air
The micromachining of Al2O3-TiC composite ceramics in air using KrF (l=248 nm) nanosecond laser pulses
was studied. The influence of the processing parameters was analysed aiming to optimise the machining
process. Surface topography, surface roughness, ablation rate and surface finish machining quality were
investigated as a function of the following parameters:
- Laser fluence;- Number of pulses;- Laser beam spot size;- Laser beam angle of incidence;- Machining with
static or moving sample.
Chapter 5 - Study of the influence of the working atmosphere on the micromachining of Al2O3-TiC ceramics
The effects of the ambient atmosphere on the ablation of Al2O3-TiC using nanosecond duration KrF (l=248 nm)
laser pulses are studied. The influence of the gas type and pressure on the ablation rate and surface
topography is investigated, and the observed changes are correlated with the ablation plume dynamics. The
mechanisms of formation of particles during ablation are studied.
Chapter 6 - Study of the influence of the excimer laser wavelength on the micromachining of Al2O3-TiC
ceramics
The micromachining of Al2O3-TiC ceramics using nanosecond ArF (l=193 nm) and XeCl (l=308 nm) excimer
lasers was studied. The effects of the laser fluence and number of pulses on the ablation rate and surface
topography were analysed. A comparative study of the ablation of Al2O3-TiC using nanosecond laser pulses at
different wavelengths (193, 248 and 308 nm) was performed.
Chapter 7 - Femtosecond excimer laser micromachining of Al2O3-TiC ceramics. Influence of the laser pulse
duration
The micromachining of Al2O3-TiC ceramics using femtosecond duration laser pulses (l=248 nm) is studied.
The results are compared with those obtained when processing is carried out using nanosecond laser pulses
at the same radiation wavelength, in order to investigate the influence of the laser pulse duration on the ablation
process.
Chapter 8 - Final conclusions and future work
The final conclusions of this study are presented. The versatility of the excimer laser projection technique in the
micromachining of Al2O3-TiC as well as the associated difficulties are summarised. Excimer laser processing
and ion beam etching of Al2O3-TiC are compared. Indications for future work are presented.
Appendix A - Thermal model
The finite-difference thermal model developed to investigate heating/ablation during irradiation with nanosecond
duration laser pulses is presented. This model was used to investigate the heating behaviour of Al2O3, TiC and
Al2O3-TiC by considering the fraction of the individual phases in the composite. It allowed to study the influence
on heating of various material properties, namely the optical absorption coefficient and thermal conductivity.
Appendix B - Dynamics of the ablation plume
The ablation plume dynamics was coupled to the finite difference model, in order to estimate the pressure and
attenuation of radiation in the plume.
_______________________________________________________________________________________
Additional Papers:
M. Mendes, R. Vilar, Debris and Particulates Formation and Deposition in UV Pulsed Laser Ablation of
Al2O3-TiC Ceramics, Proceedings of ICALEO 2000, Volume 90, Laser Microfabrication, A67-76 (2000)
M. Mendes, V. Oliveira, R. Vilar, F. Beinhorn, J. Ihlemann, Excimer Laser Micromachining of Al2O3-TiC
ceramics, Laser Assisted Net Shape Engineering 3, 623-634 (2001)
Ph.D. Thesis, M. Mendes, "Excimer laser micromachining of Al2O3-TiC ceramics. Study of the process",
244 pages (in English).
For the Complete Thesis in easy to read pdf files and additional files (see details below) a $ 5 payment is
required.
Click the PayPal button below for secure payment. You will then be given a user name/ password and a link
where all downloads are available.
If you have any difficulties contact: info@mmendestech.com
244 pages (in English).
For the Complete Thesis in easy to read pdf files and additional files (see details below) a $ 5 payment is
required.
Click the PayPal button below for secure payment. You will then be given a user name/ password and a link
where all downloads are available.
If you have any difficulties contact: info@mmendestech.com
The Thesis Chapters (as seen on this site, fully complete with results, discussion, conclusions and
bibliography) and additional papers are available in pdf with above payment.
bibliography) and additional papers are available in pdf with above payment.
Files available to download:
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