Method for Structuring and Chemically Modifying a Surface of a Workpiece

A method for structuring a surface of a workpiece, which surface comprises a metal or a metal alloy or a metal oxide layer or a metal alloy oxide layer present on a metal or metal alloy surface, the method comprising:

• producing surface structures having dimensions in the sub-micrometer range by scanning, once or several times by a pulsed laser beam, an entire surface of the metal or the metal alloy or the metal oxide layer or the metal alloy oxide layer on the metal or the metal alloy, which surface or layer is accessible to laser radiation, wherein the scanning is performed in such a way that adjacent flecks of light of the laser beam adjoin each other without an interspace in between or overlap, wherein the following conditions are satisfied
• approximately 0.07≦ε≦approximately 2300
• with
• ɛ
• =
• P
• P
• 2
• ·
• P
• m
• ·
• f
• ·
• α
• ·
• t
• ·
• κ
• d
• 2
• ·
• v
• ·
• T
• V
• ·
• c
• P
• ·
• λ
• ·
• 10
• 3
• wherein:
• Pp:
• Pulse peak power of the exiting laser radiation [kW]
• Pm:
• Average power of the exiting laser radiation [W]
• t:
• Pulse length of the laser pulses [ns], wherein t is approximately 0.1 ns to approximately 2000 ns,
• f:
• Repetition rate of the laser pulses [kHz]
• v:
• Scanning speed on the workpiece surface [mm/s]
• d:
• Diameter of the laser beam on the workpiece [μm]
• α:
• Absorption of the laser radiation of the irradiated material [%] under normal conditions
• λ:
• Wavelength of the laser radiation [nm], wherein λ=approximately 100 nm to approximately 11000 nm
• Tv:
• Boiling point of the material [K] under standard pressure
• cp:
• Specific heat capacity [J/kg·K] under normal conditions
• κ:
• Specific thermal conductivity [W/m·K] under normal conditions,
• wherein an atmosphere, in which the method is carried out, is a gas or gas mixture that reacts with the surface of the metal or the metal alloy or the metal oxide layer or the metal alloy oxide layer on the metal or the metal alloy.

A workpiece comprising:

• a surface of a metal or a metal alloy or a metal oxide layer or metal alloy oxide layer on the surface of the metal or the metal alloy, wherein the surface has a chemically modified structure that can be produced by
• scanning, once or several times by a pulsed laser beam, an entire surface of the metal or the metal alloy or the metal oxide layer or the metal alloy oxide layer on the metal or the metal alloy, which surface or layer is accessible to laser radiation, wherein the scanning is performed in such a way that adjacent flecks of light of the laser beam adjoin each other without an interspace in between or overlap, wherein the following conditions are satisfied
• approximately 0.07≦ε≦approximately 2300
• with
• ɛ
• =
• P
• P
• 2
• ·
• P
• m
• ·
• f
• ·
• α
• ·
• t
• ·
• κ
• d
• 2
• ·
• v
• ·
• T
• V
• ·
• c
• P
• ·
• λ
• ·
• 10
• 3
• wherein:
• Pp:
• Pulse peak power of the exiting laser radiation [kW]
• Pm:
• Average power of the exiting laser radiation [W]
• t:
• Pulse length of the laser pulses [ns], wherein t is approximately 0.1 ns to approximately 2000 ns,
• f:
• Repetition rate of the laser pulses [kHz]
• v:
• Scanning speed on the workpiece surface [mm/s]
• d:
• Diameter of the laser beam on the workpiece [μm]
• α:
• Absorption of the laser radiation of the irradiated material [%] under normal conditions
• λ:
• Wavelength of the laser radiation [nm], wherein λ=approximately 100 nm to approximately 11000 nm
• Tv:
• Boiling point of the material [K] under standard pressure
• cp:
• Specific heat capacity [J/kg·K] under normal conditions
• κ:
• Specific thermal conductivity [W/m·K] under normal conditions,
• wherein an atmosphere, in which the method is carried out, is a gas or gas mixture that reacts with the surface of the metal or the metal alloy or the metal oxide layer or the metal alloy oxide layer on the metal or the metal alloy.

A workpiece or workpiece composite, comprising:

• a surface of a metal or a metal alloy or a metal oxide layer or metal alloy oxide layer on the surface of the metal or the metal alloy, wherein the surface has a chemically modified structure that can be produced by
• scanning, once or several times by a pulsed laser beam, an entire surface of the metal or the metal alloy or the metal oxide layer or the metal alloy oxide layer on the metal or the metal alloy, which surface or layer is accessible to laser radiation, wherein the scanning is performed in such a way that adjacent flecks of light of the laser beam adjoin each other without an interspace in between or overlap, wherein the following conditions are satisfied
• approximately 0.07≦ε≦approximately 2300
• with
• ɛ
• =
• P
• P
• 2
• ·
• P
• m
• ·
• f
• ·
• α
• ·
• t
• ·
• κ
• d
• 2
• ·
• v
• ·
• T
• V
• ·
• c
• P
• ·
• λ
• ·
• 10
• 3
• wherein:
• Pp:
• Pulse peak power of the exiting laser radiation [kW]
• Pm:
• Average power of the exiting laser radiation [W]
• t:
• Pulse length of the laser pulses [ns], wherein t is approximately 0.1 ns to approximately 2000 ns,
• f:
• Repetition rate of the laser pulses [kHz]
• v:
• Scanning speed on the workpiece surface [mm/s]
• d:
• Diameter of the laser beam on the workpiece [μm]
• α:
• Absorption of the laser radiation of the irradiated material [%] under normal conditions
• λ:
• Wavelength of the laser radiation [nm], wherein λ=approximately 100 nm to approximately 11000 nm
• Tv:
• Boiling point of the material [K] under standard pressure
• cp:
• Specific heat capacity [J/kg·K] under normal conditions
• κ:
• Specific thermal conductivity [W/m·K] under normal conditions,
• wherein an atmosphere, in which the method is carried out, is a gas or gas mixture that reacts with the surface of the metal or the metal alloy or the metal oxide layer or the metal alloy oxide layer on the metal or the metal alloy,
• wherein, after structuring the surface, the surface is bonded with or without adhesive to a surface of a second workpiece into a workpiece composite or is provided with a coating or is chemically modified.