Effect of addition of recast materials on characteristics of Ni-Cr-Mo alloys
Curr Issues Pharm Med Sci., Vol. 32, No. 2, 71-76
1 Faculty of Mechanical Engineering, Lublin University of Technology, Nadbystrzycka 36, 20-618 Lublin, Poland
2 Department of Transporting and Agricultural Machinery, Faculty of Production Engineering, University of Life Sciences in Lublin, Głęboka 28, 20-612 Lublin, Poland
The purpose of this study was to assess the effect on selected mechanical properties, of adding recast materials to the NiCrMo alloy of newly produced castings.
Three groups of dental alloy NiCrMo (trade named Remanium CS+) were prepared by mixing 50% new alloy to alloy remnants from previous castings. The specimens in the first casting group used 100% new alloy and served as control (C1). The second group consisted of equal amounts of new alloy and alloy remnants cast only once (C2). The third group contained 50% of new alloy and alloy cast twice (C3). Microstructural analysis was performed and the chemical composition, hardness and the metal-ceramic bond strength were assessed. In addition, EDS analysis (mapping) was undertaken. Hardness and bond strength results were also statistically analysed.
In spite of the fact that recasting brought about small changes in hardness and chemical composition (C, Cr and Mo), these effects were found to not affect their functional properties in the oral cavity. Still, significant differences between new alloy and the recasted groups (p < 0.05) were demonstrated in the course of statistical analysis of Vickers hardness test (for α = 0.05). All analysed research groups have a similar average adhesion at 48.51÷49.24 MPa (p > 0.05).
The recasting procedure described in the paper can be done safely in dentistry. If previo-usly casted material is used, it should be mixed with new material. The use of the material prepared in this way can lower the costs of NiCrMo castings.
nickel alloys, metal-ceramic bonding, three-point bond test, recasting.