CORROSION RESISTANCE OF A GOLD-TITANIUM ALLOY TI6AL4V WELD PRODUCED IN A DENTAL LASER WELDING MACHINE

Abstract

The corrosion resistance of the Ti6Al4V titanium alloy in combination with gold may increase or decrease, which is related to the amount of gold in the alloy. The aim of the work was to assess the weldability of pure gold with the Ti6Al4V titanium alloy using a prosthetic laser welding machine, and to assess the corrosivity. In the research was used a calibrated 24k gold wire with a diameter of 0.4 mm. The wire was welded to the surface of the Ti6Al4V titanium screw used in the connection of the prosthetic superstructure connector with an implant. For welding, a Bego Laser Star plus prosthetic laser welding machine was used. The samples were placed in resin, ground (500-4000 SiC), polished (Al2O3 slurry. An electrochemical corrosion test was carried out, simulating the potential formation of pitting corrosion, in a solution of artificial saliva, consisting of two stages: a. determination of the stationary potential in no-current conditions for 1 h until stabilization (Eocp - opec circuit potential), b. potentiodynamic test initial potential E start = Eocp-100 mV to E final = 2 V or the occurrence of the second condition: anode current density 1 mA /cm2, the potential increase rate of 1 mV/s, and then the samples were observed using light microscopy and SEM, and an attempt was made to identify corrosion products using EDS. The paper evaluates the possibility of gold welding with the Ti6Al4V titanium alloy in the conditions of a prosthetic laboratory, limitations in this process were indicated, and conclusions that could improve weldability were indicated. The heat affected zone was identified and the results of corrosion tests were evaluated. The weldability of gold with the mentioned titanium alloy was confirmed, however, in subsequent tests, attempts should be made to reduce the laser spot, which will reduce the heat affected zone. Traces of corrosion were found, but they were rare and even over the entire surface of the samples.