Transverse strength, ductility, and qualitative elemental analysis of cobalt-chromium alloy after various durations of induction melting.
OBJECTIVE
The aim of this study was to compare the transverse strength and ductility of bars cast from cobalt-chromium alloy that had been melted for various lengths of time (n = 5 per group). To determine its elemental composition, the cobalt-chromium alloy was also analyzed qualitatively.


METHODS
Transverse strength and ductility of the cobalt-chromium bars was measured by a three-point loading test. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) were used to determine the composition of the samples compared with unmelted cobalt-chromium alloy.


RESULTS
The transverse strengths of the test bars cast from the cobalt-chromium alloy, which had been induction-melted for various lengths of time, did not differ significantly (p = .056); but the ductility of the test bars was affected by the duration of induction melting of the alloy (p < .001). According to the SEM/EDS analysis, the amount of silicon in the cobalt-chromium alloy decreased with lengthening duration of induction melting of the alloy.


CONCLUSIONS
This study supports the previous finding that good resistance to deflection fatigue is correlated with increased ductility of cobalt-chromium alloy and vice versa.
Vallittu
P K
PK
Department of Prosthetics and Stomatognathic Physiology, NIOM Scandinavian Institute of Dental Materials, Haslum, Norway.
D000704:Analysis of Variance; D055598:Chemical Phenomena; D002627:Chemistry, Physical; D002858:Chromium Alloys / Q000737:chemistry*; D003722:Dental Alloys / Q000737:chemistry*; D016734:Dental Clasps; D004548:Elasticity; D008422:Materials Testing / Q000295:instrumentation / Q000379:methods / Q000706:statistics & numerical data; D008669:Metallurgy; D008855:Microscopy, Electron, Scanning; D013499:Surface Properties; D013718:Tensile Strength; D013997:Time Factors
D002858:Chromium Alloys; D003722:Dental Alloys