An analysis of the influence plasma nitriding of cobalt chromium alloy on its surface properties

Cilj ovog rada bio je proučiti kobalt-krom superlegure koje imaju visoku otpornost na koroziju, otpornost na trošenje, visoku tvrdoću i čvrstoću. Međutim, primjenom u biomedicinskom području i strojogradnji dolazi do izraženih djelovanja triboloških i korozijskih mehanizama. S vremenom dolazi do trošenja i propadanja kobalt-krom legura u takvim uvjetima. Rješenje se nudi putem suvremenih metoda inženjerstva površina. U eksperimentalnom dijelu ovoga rada proveden je postupak modificiranja procesom niskotemperaturnog nitriranja u plazmi. Nakon što su uzorci kobalt-krom legure podvrgnuti nitriranju u plazmi napravljene su analize kemijskog sastava, parametara hrapavosti i morfoloških promjena na površinama. Nakon analiza uspoređeni su rezultati osnovnog i nitriranog stanja uzoraka. Rezultati provedenih ispitivanja potvrđuju da je nitriranje uspješno provedeno te kao takvo primjenjivo na kobalt-krom legure koje imaju primjenu u specifičnim područjima s naglašenim tribokorozijskim djelovanjem.The goal of this paper was to study the cobalt-chromium superalloys which have high resistance to corrosion and wear, high hardness and firmness. However, by using those alloys in areas of biomedicine and enginnering a strong influence of tribocorotic and corrosive mechanism is occuring. Over time, corrosion and wear of cobalt-chromium alloys occurs in such conditions. The solution for this problem can be found in modern methods of engineering the surfaces. In the experimental part of this work a procedure of low-temperature plasma nitriding is conducted. After the samples of cobalt-chromimum alloy were subjected to plasma nitriding, the analsys of chemical composition, parameters of roughness and morphological changes on surfaces were made. After the analyis, the results of the untreated and nitrided state of the samples were compared. Based on the results, the nitriding has been successfully performed and as such applicable to cobalt-chromium alloys having application in specific areas with pronounced tribocorrosion activity