Influence of Temperature and Wavelength on Optical Behavior of Copper Alloys

Abstract

Quantitative measured values for absorption of copper and its alloys are jet unknown in the temperature range between 30 °C and 500 °C which has to be passed before material melts in the initial phase of laser beam welding. Thus this paper investigates temperature and wavelength dependent absorption for VIS and IR wavelengths. For this purpose specimens of copper and copper alloys are heated up and reflected laser light from the surface is measured by using an Ulbricht sphere in combination with a photodiode. During welding processes inert gases are in use to reduce oxidation. Hence the influence of shielding gases on the absorption will also be taken into account during the heating process of the specimens. Consequently this paper provides results for the temperature dependent absorption of copper and copper alloys for different wavelengths at atmospheric conditions and argon shielding.

Why Color Matters—Proposing a Quantitative Stability Criterion for Laser Beam Processing of Metals Based on Their Fundamental Optical Properties

“…The subject of temperature dependence of the absorptivity of copper at visible wavelengths in general has been ignored, even in current simulative studies, using temperature-independent values [79][80][81]. In the few cases of attempts to research or measure data for different temperatures and states at visible wavelengths, the reversed temperature dependence of the absorptivity was either attributed to oxide layers [82] or dismissed as implausible [14]. In many experimental publications on copper welding, this issue is circumvented by stating the increasing absorptivity with temperature and the additional absorptivity jump at the phase change for λ = 1 µm, together with the trend of increasing room-temperature absorptivity with decreasing wavelength [4,[83][84][85].…”

Implementation of Micro-EDM Monitoring System to Fabricate Antimicrobial Nanosilver Colloid

“… Wavelength of the highest absorption peak: Nanoparticles will radiate under the stimulation of certain wavelengths. For example, nanosilver has the highest absorption value around 400 nm [ 36 ], while nano-copper is around 280 nm [ 37 ]. …”