An observation on the initiation of micro-pitting damage in as-ground and coated gears during contact fatigue

► Origin of micro-pitting in gears. ► Micro-pitting in as-ground and coated gears. ► Initiation of micro-pitting in uncoated and coated gears. ► Resistance to micro-pitting in coated gears. ► Contact fatigue behaviour of as-ground and coated gears.