Alloying of Ohmic Contacts to n-Type 4H-SiC via Laser Irradiation

2013 ◽  
Vol 740-742 ◽  
pp. 773-776 ◽  
Author(s):  
A. Hürner ◽  
T. Schlegl ◽  
B. Adelmann ◽  
H. Mitlehner ◽  
R. Hellmann ◽  
...  
Keyword(s):  
Laser Beam ◽  
Contact Resistance ◽  
Ohmic Contacts ◽  
Continuous Wave ◽  
Laser System ◽  
Beam Power ◽  
Voltage Measurement ◽  
Processing Times ◽  
Laser Beam Power ◽  
Beam Propagation Factor

In this study, we present the results of alloying nickel as ohmic contact material to n-type 4H-SiC via a continuous wave fiber laser with different laser beam powers and processing times. The laser system exhibits an emitting wavelength of 1070 nm and a beam propagation factor M2 smaller than 1.1. Contact resistance was determined by current-voltage measurement using the two-terminal contact resistance method. The results indicate that a laser beam power of at least 100 W is mandatory to initialize contact silicidation. Although the contact resistance is improvable by longer processing times, our experiments outline the much higher impact of laser beam power to contact silicidation compared with processing time. For laser beam powers of 300 W and processing times of 0.5 s a contact resistance of 6.5 , comparable to contacts alloyed in a lamp heated furnace at 910 °C for 2 min with a contact resistance of 10.3 , was achieved.

scholarly journals Mechanical Properties of Fibre Laser Welded AZ31B Sheets and their Dependence on the Spot-Size

2015 ◽  
Vol 828-829 ◽  
pp. 298-304
Author(s):  
Stefan Riekehr ◽  
Riccardo Ravasi ◽  
Josephin Enz ◽  
Volker Ventzke ◽  
Nikolai Kashaev
Keyword(s):  
Laser Beam ◽  
Laser System ◽  
Base Material ◽  
Spot Size ◽  
Fibre Laser ◽  
Beam Power ◽  
Spot Diameter ◽  
Laser Beam Power ◽  
Focus Spot ◽  
Weld Area

In the present work the mechanical behaviour of laser beam welded AZ31B alloy was studied, by changing systematically the spot size of the used fibre laser system between 200 µm and 1000 µm at different power levels between 2 kW and 8 kW. Maximum welding velocities with respect to imperfections were determined. The characterization of the obtained welds - in terms of Vickers hardness, UTS, Af and weld width, resp. weld area - was correlated with the micro-texture in dependence of the different Focus Spot Diameters and Laser Beam Power levels as well as the resulting cooling rates. Highest UTS of 94% of the base material was achieved with 200 µm Focus Spot Diameter and Laser Beam Power of 4 kW at welding velocity of 100 mm/s. By increasing the Focus Spot Diameter to 600 µm, the tensile strength was reduced to 86 % of the actual strength of the base material.

scholarly journals The influence of laser re-melting on microstructure and hardness of gas-nitrided steel

2016 ◽  
Vol 36 (1) ◽  
pp. 18-22 ◽  
Author(s):  
Dominika Panfil ◽  
Piotr Wach ◽  
Michał Kulka ◽  
Jerzy Michalski
Keyword(s):  
Laser Beam ◽  
Laser Treatment ◽  
Diffusion Zone ◽  
Nitrided Layer ◽  
Nitriding Process ◽  
Beam Power ◽  
Gas Nitriding ◽  
Nitrided Steel ◽  
Laser Beam Power ◽  
And Diffusion

Abstract In this paper, modification of nitrided layer by laser re-melting was presented. The nitriding process has many advantageous properties. Controlled gas nitriding was carried out on 42CrMo4 steel. As a consequence of this process, ε+γ’ compound zone and diffusion zone were produced at the surface. Next, the nitrided layer was laser remelted using TRUMPF TLF 2600 Turbo CO2 laser. Laser tracks were arranged as single tracks with the use of various laser beam powers (P), ranging from 0.39 to 1.04 kW. The effects of laser beam power on the microstructure, dimensions of laser tracks and hardness profiles were analyzed. Laser treatment caused the decomposition of continuous compound zone at the surface and an increase in hardness of previously nitrided layer because of the appearance of martensite in re-melted and heat-affected zones

Laser beam power fade induced by system and atmospheric effects

1982 ◽  
Vol 21 (13) ◽  
pp. 2432 ◽  
Author(s):  
U. Halavee ◽  
M. Tamir ◽  
E. Azoulay
Keyword(s):  
Laser Beam ◽  
Beam Power ◽  
Atmospheric Effects ◽  
Laser Beam Power ◽  
Power Fade

scholarly journals Manufacturing Technology and Properties of Fe/TaC Metal Matrix Composite Coatings Produced on Medium Carbon Steel Using Laser Processing—Preliminary Study on the Single Laser Tracks

Materials ◽  
2021 ◽  
Vol 14 (18) ◽  
pp. 5367
Author(s):  
Dariusz Bartkowski
Keyword(s):  
Laser Beam ◽  
Metal Matrix Composite ◽  
Matrix Composite ◽  
Laser Processing ◽  
Metal Matrix ◽  
Steel Substrate ◽  
Composite Coatings ◽  
Tantalum Carbide ◽  
Beam Power ◽  
Laser Beam Power

The paper presents study results of Fe/TaC metal matrix composite coatings produced on tool steel using laser processing of TaC pre-coat. The Fe/TaC coatings were produced in two steps. First, a pre-coat in the form of a paste based on tantalum carbide and water glass was made and then applied to the steel substrate. In the second step, the TaC pre-coat was remelted with steel substrate using a diode laser beam with a rated power of 3 kW. A constant scanning speed of the laser beam of 3 m/min and three types of laser beam power: 500 W, 800 W and 1100 W were applied. Tests were carried out on three different thicknesses of the TaC pre-coat: 30 µm, 60 µm and 90 µm. The influence of pre-coat thickness and laser beam power on the microstructure, chemical composition and microhardness were analyzed. A possibility of producing coatings with a characteristic composite structure was found, where the iron from the substrate became the matrix, and the introduced tantalum carbides—the reinforcing phase. It was found that too high power of the laser beam leads to complete melting of the introduced primary TaC particles. It was also found that the use of a thicker TaC pre-coat contributes to microhardness increase.

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