How does adding the carbonitride coating give you a product that is different from case-hardening?

Carbonitriding is actually a variation on the case-hardening technique. This technique involves heating a blade edge to around 1600°F, inducing a phase change in the material. Nitrogen and carbon atoms are introduced at this phase change and they diffuse into the material. Depending on the steel used, this generally allows for a greater case depth in comparison to nitrocarburizing, another type of case-hardening technique. In the steels used for Camillus blades, we have found that carbonitrization results in blades that are are more resistant to wear and have increased fatigue strength over other case-hardening techniques.