title: New high-palladium casting alloys: studies of the interface with porcelain.
abstract: This investigation studied the metal ceramic interface for two representative high-palladium alloys each of the Pd-Cu-Ga and Pd-Ga systems, using scanning electron microscopy and x-ray energy dispersive spectroscopy. The Pd-Cu-Ga alloys produced complex subsurface oxidation regions with thickness ranging from 15 to 20 microns for one alloy and 5 to 10 microns for the other alloy. Ga, In, and Sn accumulated at the interfaces, and Ga-rich deposits were found in the subsurface scale. One Pd-Ga alloy presented a surface oxidation region which dissolved in the ceramic, producing "islands" rich in Pd and Ga with a width that ranged from 1 to 2 microns. These islands were separated from the alloy by a band rich in Ga and Si which was 1 to 2.5 microns thick. While the other Pd-Ga alloy presented similar interfacial microstructures, the "islands" formed for this alloy were relatively sparse. The Pd-Cu-Ga alloys had a more favorable interface for metal ceramic bonding, which agrees with previous characterization of bond failures between these alloys and dental porcelain.
authors.affiliation: Ohio State University College of Dentistry, Section of Restorative Dentistry, Prosthodontics, and Endodontics, Columbus 43210-1241, USA.
authors.forename: E
authors.initials: E
authors.lastname: Papazoglou
authors.forename: W A
authors.initials: WA
authors.lastname: Brantley
authors.forename: J C
authors.initials: JC
authors.lastname: Mitchell
authors.forename: Z
authors.initials: Z
authors.lastname: Cai
authors.forename: A B
authors.initials: AB
authors.lastname: Carr
mesh_terms: D003300:Copper / Q000737:chemistry; D003722:Dental Alloys / Q000737:chemistry*; D001840:Dental Bonding; D003776:Dental Porcelain / Q000737:chemistry*; D004577:Electron Probe Microanalysis; D005708:Gallium / Q000737:chemistry; D016876:Metal Ceramic Alloys; D008855:Microscopy, Electron, Scanning; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry; D010165:Palladium / Q000737:chemistry*; D013499:Surface Properties; D013816:Thermodynamics
chemical_list: D003722:Dental Alloys; D016876:Metal Ceramic Alloys; D010087:Oxides; D003776:Dental Porcelain; D010165:Palladium; D003300:Copper; D005708:Gallium