The laser surface texturing of coated glass by picosecond laser with 355nm wavelength strongly absorbed by the glass is reported. The texturing was performed using various pulse energy and the distance of ablative single mark on the coated glass surface. In the performed experiment it was possible to control for the surface’s optical reflectance.
Absorptance is the base parameter that is determining the energy coupling of a laser radiation into workpiece during its laser treatment. The absorptance for AlSi12/SiCp composites along with their temperature’s dependence for the AlSi12 alloy matrix and for wavelengths that correspond to DL, Nd:YAG and CO2 lasers were investigated. Based on the absorptance, the characteristic laser energy densities at which the surface of the metal matrix composite reaches melting temperature were estimated. This estimation was crucial in order to find the bottom level of energy densities, i.e. operational parameter window for AlSi12/SiCp laser melting. Using higher energy densities than the characteristic the surfaces of the AlSi12/SiCp were remelted. In this process the industrial Diode and Nd:YAG lasers were used. Laser remelted composites were subjected to methods of XRD, hardness and residual stress tests. The tests showed that the control of the laser energy density during the laser treatment of the AlSi12/SiCp allowed to obtain a refine structure of the composite matrix. This refine structure is advantageous for the improvements in hardness and corrosion-resistant of the investigated AlSi12/SiCp composite surface.
The antimony sulfoiodide (SbSI) single crystal being a ferroelectric semiconductor has a large number of interesting properties. Based on SbSI single crystal a new type of heterostructures has been produced. For the first time diodes, transistors and thyristors composed of SbSI/Sb2S3 heterojunctions have been fabricated by CO2 laser irradiation of selected sections of SbSI single crystals. Treated sections are composed of amorphous antimony (III) sulphide (Sb2S3) with energy gap 0.3 eV smaller (in room temperature) than that of SbSI. The structural optical, electrical and photoelectrical characteristics of produced devices have been investigated.
This paper presents a physical model characterizing the geometry of gas-assisted laser cutting of the AlSi-alloy/SiCp
composite. In the model, a lot of relevant parameters that describe the inhomogeneous optical and thermophysical
properties of AlSi-alloy/SiCp have been used. Numerical evaluations of this model give some explanations of "double
slope" formation mechanism during laser cutting of the AlSi-alloy/SiCp. The theoretical results are compared with
experimental data. It is found that increasing laser beam scanning speed increases the slope of cutting front.
Trials of welding an alloy based on an intermetallic Fe-Al phase matrix with a diode laser have been made. Metallographic research has revealed typical structures, characteristic of welding joints. A possibility of laser joining of Fe-Al alloys has been found.
Trials of wlding an alloy based on an Ni3Al phase matrix with a diode laser have been made. In the base metal of Ni3Al, typical casting structures have been found. The Heat Affected Zone consists of a fine-grained structure, whereas in the weld structure, columnar crystals have been observed. A possibility of joining intermetallic phase-based alloys by measn of a diode laser has been affirmed.
Thin film of hydrogenated amorphous silicon (a-Si:H) were annealed using CO2 laser radiation ((lambda) equals10,6 micrometers ). The influence of this laser treatment on spectral dependencies of real part of refractive index and absorption coefficient of light in a-Si:H are presented. The values of energy gap have decreased while the Urbach energy increased after CO2 laser annealing of a-Si:H. The conductivity and photoconductivity of the annealed material have decreased. The power coefficient of the light intensity dependence of photoconductivity has also changed. The influence of CO2 laser irradiation on the energetic distribution of electron states of a a-Si:H is reported.