The Influence of Temperature During Ceramic Firing Cycles on the Microstructure of Co-Cr Alloys

Dentalit C je neplemenita Co-Cr legura koja se na našoj klinici primjenjuje za kovinsko-keramičke radove. Odljevi kobalt-krom legura pokazuju grubozrnatu, dendritnu strukturu. Svrha ispitivanja bila je ustanoviti utječe li ciklus pečenja keramičkih slojeva na mikrostrukturne promjene i na vrijednosti mikrotvrdoće metalne podloge. Izrađena je dvadeset i jedna krunica i podvrgnuta uobičajenim fazama pečenja keramičkih slojeva. Mikrostruktura je ocijenjena svjetlosnim i skening elektronskim mikroskopom. Mikrotvrdoća uzoraka mjerena je metodom po Vikersu, opterećenjem od 1 N. Rezultati ispitivanja pokazali su da temperatura pečenja keramike neznatno utječe na mikrostrukturne promjene legure. Nije utvrđen značajan porast vrijednosti mikrotvrdoće.Dentalit C is one o f nonprecious alloys introduced to our clinic for ceramicmetall restorations. In the as-cast condition cobalt-chromium alloy has a coarse dendritic structure. The aim o f this study was to determine if the ceramic firing cycles has any influence on the microstructure and on microhardness o f based metal. Twenty one crowns were casted and subjected to common fa zes o f ceramic bake cycles. Microstructure were estimated by light optical and by scanning electron microscopy. Microhardness was measured by Vickers method with loading o f 1 N. The results showed that the fused temperature has little effect on microstructure changes. Values o f hardness didn’t increase significantly