Abstract
To develop porcelain-facing alloys for conical double-crown telescopic prosthesis, we manufactured several alloys by adding one of four elements (Zr, B, V, and W) to the Co-Cr alloy containing 2% titanium. The physical and mechanical properties and the bond strength of these alloys were examined.
As the result, the following were obtained:
1. The addition of boron markedly lowered the melting point of the alloy. It is difficult to use boron in the porcelain-facing alloy.
2. The addition of wolfram adversely affected the physical and mechanical properties of the alloy.
3. The addition of zirconium caused no marked change in the physical or mechanical properties of the alloy.
4. The addition of vanadium altered the tensile strength of the alloy, without markedly affecting any other property of the alloy.
5. The addition of all 4 elements reduced oxide formation.
6. The structure of the cast alloy was altered by the addition of B; however, it was not possible to presume any relationship between this change and the physical or mechanical properties.
7. The bond strength was elevated by the addition of zirconium (in particular when fusing porcelain to metal at 1, 050°C under reduced pressure).
This change was accompanied by improved desquamation.
