Soldering strength of post-soldering of palladium-based metal-ceramic alloys

To evaluate the post soldering of metal-ceramic alloys that have palladium as their main component, palladium-based metal-ceramic alloys with different compositions were used to assess soldering strength. Four palladium-based metal ceramic alloys were selected: Pd-Cu system, Pd-Ag system, Pd-Ni system, and Pd-Sb system, and gold-silver-palladium alloy was also used. As soldering materials, 12 k gold solder and 16 k gold solder were used. After post-soldering by butt joint samples that had been heat treated (equivalent to the porcelain firing cycle), soldering strength was evaluated by measuring the flexural strength. The yield strength had a range of 300 to 800 MPa, and the ultimate strength was in the range of 350 to 1,000 MPa; the Pd-Ag type showed the highest value. There was no correlation between the yield strength of the metal-ceramic alloys and that of the soldering samples. When the soldering strength of 12 k gold solder and 16 k solder were compared, the samples soldered with 12 k gold solder showed higher values in all cases. Samples in which heating was prolonged for 10 seconds had a high strength, within 100 to 500 MPa in yield strength and 100 to 800 MPa in ultimate strength.