Carburizing vs Nitriding

Which heat treatment method is better for precision gears? Both carburizing and nitriding are acceptable heat treating methods for precision gearing. Through engineering, development, and testing, Onvio has determined that carburized gears offer critical advantages for precision gearboxes.


Carburized gears feature a significantly deeper hardened layer whose hardness gradually decreases to the core hardness. This structure provides superior surface contact fatigue properties and ductility/impact resistance and strength of the core. In addition, sufficient case depth obtained in the carburizing process is required as a needle roller bearing surface in the planet gears.

Nitrided gears can have a “white layer” on the surface which is very hard and brittle. If not removed it can be prone to flaking and cracking leading to heavy surface fracture and gear failure. The hardened case depth is significantly thinner than in similar carburized gears and transitions to the core hardness immediately behind the case.


While both technologies offer very good surface hardness, Onvio believes that the depth penetration of carburized gears provides our customers with superior performance and reliability for their demanding applications.

More Questions?
Let Onvio’s team of engineers work for you.

Carter Greene
National Sales Manager
Phone 847-230-0653

Onvio LLC Headquarters
20 Northwestern Drive, Salem, NH 03079