Process for applying a surface coating
AssigneesHeidelberger Druckmaschinen AG, Winterthurer Metallveredelung AG
InventorKarl Mull
Life of this patent
Estimating the term…
Abstract
A structured surface coating is electrochemically deposited on an electrically conductive surface of a component. The component to be coated forms the cathode in a galvanic bath. The process current is raised in discrete steps in a nucleation phase during which island formations are deposited on the surface, with brief pauses between each increase of between 0.1 and 30 sec. The process current is then maintained at a constant level, during which the islands grow. The process sequence may be repeated several times.
Claims14
An improved process for electrochemically depositing a surface coating, wherein a component is subjected to a galvanic bath and the surface coating is deposited on the component with a structured outer surface topography, by forming a plurality of island formations of deposition material on a surface of the component by providing an electrical waveform as a source of electrical energy, and causing a growth of the deposition material on the plurality of island formations for forming the structured outer surface topography with a follow-up waveform as the source of electrical energy during a growth working period, the improvement which comprises:
- increasing a strength of a current density of the electrical waveform during the step of forming the plurality of island formations in a plurality of steps with a waiting period between respective step increases of the plurality of steps of 0.1 to 30 seconds;
- subsequently causing growth of the deposition material on the islands with a follow-up waveform having a current density during the growth working period:
- decreasing the strength of said current density of the follow-up waveform to an end value after the growth working period;
- and
- cyclically repeating the afore-recited process steps between two and twenty times, and in repetition utilizing the end value of a preceding cycle as a starting value of a respectively following cycle;
- wherein the structured outer surface topography is formed without mechanical and chemical after treatment steps after a last growth step follow-up waveform has been removed.
A process for electrochemically depositing a structured surface coating on a machine component, which comprises:
- a) connecting a machine component in a direct current loop and defining an electrical parameter as one of an electric voltage and electric current;
- b) immersing the component in a galvanic bath;
- c) subjecting the component to a starting waveform of the electrical parameter, for forming islands of deposition material on a surface of the component;
- d) adjusting the current density of the starting waveform by increasing a strength of the current density during the step of forming the island deposition material in a plurality of steps with a waiting period between respective step increases of the plurality of steps of 0.1 to 30 seconds;
- e) subsequently causing a growth of the deposition material on the islands with a follow-up waveform of the electrical parameter in a growth step;
- f) decreasing a strength the follow-up waveform of the electrical parameter to an end value;
- and
- g) cyclically repeating steps c)-f) between two and twenty times, and in repetition utilizing the end value of a preceding cycle as a starting value of the at least one starting waveform of a respectively following cycle;
- wherein the structured surface coating is formed without mechanical and chemical after treatment steps after a final growth step follow-up waveform has been removed.
Dependencies are inferred from the claim text.