Surface Technology Flashcards
What is the most common type of coating?
Galvanic
Typical zinc coating thickness for automotive applications
5-10 μm
What makes zinc coatings especially corrosion resistance?
Damage in the coating heals itself when the Zn corrodes instead of the steel and creates an oxide layer which continues to protect the steel
Can steel be copper plated?
No, it must be nickel plated first
What type of coating takes place when steel is dipped into molten zinc?
Hot dip galvanizing
What are the different Zn coating methods and describe them
Daniell-Element-Electrochemical cell (describe its general layout and what its used for)
A type of electrochemical cell the uses a Zn electrode (anode) submerged in a zinc sulfide solution which is connected to a copper electrode (cathode) submerged in copper (II) sulfate. Also called a galvanic cell this setup can be used to plate steel with different metals.
What properties does a metal need in order for it to be used as a sacrificial anode for steel?
It must be more electronegative than Fe
What are the differences between drum coating and dip coating?
Drum coating coats thousands of small components (namely hardware) at the same time be tumbling them in a drum filled with the electrolyte. The coating on the parts comes out damaged due to this tumbling method. Dip coating coats only a handful of components (what will fit of the rack) but it ensures an even coating for parts where that is crucial.
