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Abstract

The properties of an alloy with 65% Pd, 30% Co and 5% Ga have been investigated with consideration to the requirements of a ceramic fusing alloy. The composition of the alloy was at the outset chosen because of a reasonably low melting point of 1200°C. The mechanical properties were found to be satisfactory (σ0.2≈ 530 MPa, total elongation ≈5%). The bond strength between the alloy substrate and the ceramic were measured in 4 point bending to be at least 36 MPa. The fractures occurred in the epoxy glue of the particular bend specimen construction, and the strength was regarded as adequate. During the oxidation procedure prior to ceramic veneering, a dark oxide film consisting of predominantly of CoO was formed. The use of a gold coating agent instead of preoxidation caused an equally high bond strength to the ceramic. The coefficient of thermal expansion was measured to be 14.4 10−6/°C, which can be considered to be adequate and close to that of most dental ceramics for veneering. The castability was found to be satisfactory. The only detected drawback of the alloy was a definite tendency to absorb carbon when melted in a graphite crucible.

Reference
A new dental Pd-Co alloy for ceramic veneering.
Syverud M, Kvam K, Herø H
Dental Materials 1987 Jun; 3(3): 102-106