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1. The effect of temperature on the surface carbon and nitrogen content of the co infiltrated layer

 

As the co infiltration temperature increases, the nitrogen content in the co infiltration layer decreases; The carbon content first increases, but decreases after reaching a certain temperature.

 

2. The effect of co infiltration time on the content of C and N in the co infiltration layer

 

At the initial stage of co infiltration (≤ 1 hour), the concentration of C and N on the surface of the infiltration layer increases simultaneously with time. Continuing to extend the co infiltration time, the surface carbon concentration continued to increase, but the nitrogen concentration actually decreased.

 

3. The mutual influence of C and N

 

In the early stage of co infiltration, nitrogen atoms penetrate into the surface of the workpiece, causing its A3 point to decrease, which is conducive to the diffusion of carbon atoms. As nitrogen atoms continue to penetrate, carbon nitrogen compounds will form in the infiltration layer, which in turn hinders the diffusion of carbon atoms, and carbon atoms also hinder the diffusion of nitrogen atoms.

 

4. Characteristics of carbon nitrogen co infiltration

 

(1) Low processing temperature can reduce workpiece deformation and reduce energy consumption.

 

(2) The infiltration layer has good hardenability and resistance to tempering.

 

(3) In the early stage of carbon nitrogen co infiltration, there is a relatively fast infiltration rate, and the carbon nitrogen co infiltration layer is generally controlled within the range of 0.2-0.75mm. The surface layer contains more than 0.6% carbon (w) and nitrogen (w) between 0.1 and 0.4.