Mechanical, thermal, and chemical analyses of the binary system Au-Ti in the development of a dental alloy

Abstract

Investigations in the binary system gold-titanium (Au-Ti) were performed in regard to the development of a universal dental alloy suited for inlays, for the conventional crown and bridge technique, as well as for the ceramic-fused-to-metal technique. With nine alloys with increasing Ti content from 0-10 atom %, microstructure, mechanical properties, thermal properties, and corrosion were determined in the as-cast state and after simulation of ceramic firing. The microstructure shows an increasing formation of a second phase with increasing Ti content, crystallizing dendritically, which, according to the binary phase diagram must be the intermetallic phase TiAu(4). The results of the measurements reveal that with increasing Ti content, hardness, Young's modulus, proof stress, and tensile strength strongly increase in the range of 2-6 atom % Ti and with higher Ti content remain constant. Elongation after fracture decreases with a Ti content above 2 atom %. The coefficient of thermal expansion decreases linearly with increasing Ti content. Thermal distortion decreases exponentially with increasing Ti content. The corrosion test showed an increasing release of Ti with increasing Ti content. Lowest corrosion was observed in the simulated state with intact oxide layer. Appropriate properties for dental application were found in the range of 6.5 at% Ti.

High hardness in the biocompatible intermetallic compound β-Ti 3 Au

“…Biomedical applications of both Ti-rich and Au-rich alloys have been previously explored in detail ( 19 , 25 , 29 , 30 ). Although hardness values showed modest increase in both these regimes of the Ti–Au solution [ Fig.…”

“…This finding suggests that Au is a suitable alloying candidate to increase the hardness in Ti binary alloys, given its nearly twofold density increase over Cu or Ag (19)(20)(21)(22). The current wide use of Au-based implant devices (25)(26)(27)(28) is testament to its biocompatibility and corrosion resistance (10).…”

Ternary Phase Diagram of Model Dentin Adhesive Exposed to Over-wet Environments

“…Phase diagrams have not been used in the dental research field, except for dental alloys (Fischer, 2000;Luciano et al, 2005). The aim of the present investigation was to create, for the first time, a ternary phase diagram of a model dentin adhesive composed of hydrophobic BisGMA, hydrophilic HEMA, and water.…”

Electrochemical Properties and Released Ions of Au-1.6mass%Ti Alloy

“…On the other hand, the activity of Au (aAu) in Au-1.6Ti alloy is shown in Equation (10) . Since the activity coefficient ( y ) of Au in Au-1.6Ti alloy was unknown, the a phase which composed the Au-1.6Ti alloy was assumed as a regular solution for the range of 0-1.6 mass% Ti; and hence y =1 was used.…”