Investigation into possibilities for application of plasma nitriding of hard metals

Istražen je učinak modificiranja površine postupkom nitriranja u plazmi na karakteristike površinskih slojeva tvrdih metala na bazi WC-Co, te je uspoređeno stanje površine prije i nakon provedenog postupka nitriranja u plazmi. U eksperimentalnom dijelu rada koristili su se uzorci tvrdih metala oznake prema JUS-ISO sustavu: P10 i K10. U ovom radu, prikazat će se postupak nitriranja u plazmi tvrdih metala s kobaltom kao vezivnim metalom u svrhu karakterizacije površine uzoraka te usporedbe stanja površina prije i nakon provedenog postupka nitriranja u plazmi. Postupak nitriranja u plazmi proveden je u Laboratoriju za toplinsku obradu Fakulteta strojarstva i brodogradnje Sveučilišta u Zagrebu. Analiza morfologije površinskih slojeva izvršena je u Laboratoriju za materijalografiju FSB-a. Ispitivanje slobodne površinske energije i kuta kvašenja provedeno je na Katedri za tiskovne forme, Grafičkog fakulteta Sveučilišta u Zagrebu. Mjerenja parametara hrapavosti površine provedena su na Katedri za mjerenje i kontrolu FSB-a. Ovaj rad se temelji na prethodnim istraživanjima gdje su dokazane dvije ključne činjenice: - da postoji mala topivost N u Co na temperaturi nižoj od tališta Co. [1] - uspješno je dobiven spoj Co4N reakcijom Co i NH3 na temperaturi 380°C. [2]The effect of a plasma nitration surface treatment on the characteristics of the surface layers of hard metals based on WC-Co was investigated, the surface layers were compared before and after the process of nitration. In the experimental part, hardmetal samples were used according to the JUS-ISO system: P10 and K10 on which plasma nitration was performed. The plasma nitration process was performed at the Heat Treatment Laboratory of the Faculty of Mechanical Engineering and Naval Architecture of the University of Zagreb. Surface layer morphology analysis was performed at the FSB Material Laboratory. Examination of free surface energy and dewatering angle was carried out at the Department of Graphic Arts, Faculty of Graphic Arts, University of Zagreb. Measurement of surface roughness parameters was performed at the FSB's Measurement and Control Department. In this paper, the process of plasma nitration is shown on the hardmetals with cobalt binder for the characterization of the surface of the samples and the comparison of surface condition before and after the plasma nitration process. This paper is based on previous research where two key facts have been proven: - that below melting point of Co there is low solubility of N in Co. [1] - by reaction of Co and NH3 at 380 °C, a Co4N compound was obtained. [2