Sentence:  The ‘<WSD>nitrox</WSD>' process basically supplies the surface hardness of the sursulf process, which is essentially carbonitriding, and then oxidizes it. The oxide is adherent and thus considerably increases the corrosion resistance. 
Meaning of the word marked with <WSD> tags:  An industrial process for case hardening (imparting greater surface hardness to) metal objects, involving nitrocarburizing (the diffusion of carbon and nitrogen into the metal) followed by oxidation.