Effects of the Current Used on Determining a Critical Temperature by Electrical Resistivity Measurements in Dental Alloys

Abstract

The electrical resistivity measurement to determine a critical temperature (Tc) in a stoichiometric CuAu alloy is discussed on the dependence of the current used. The tempetrature was measured on two ways: With the thermocouple connected to the specimen by spot-welding, and with them separated. In the latter case, the greater the current, the lower the apparent Tc because of the generation of Joule heat. To obtain a more precise Tc, the current should be as small as possible or the thermocouple should be located as close as possible to the specimen. It is highly desirable for the thermocouple and the specimen to be welded together, if the effects of some contamination can be ignored in measuring system.

L10 nanotwinned gold-rich Au–Cu–Pt

“…The addition of Pt to the binary Au-Cu system leads to property improvements; Au-Cu-Pt alloys are thus often used in dentistry [16][17][18]. Investigations aimed at understanding the mechanism of ordering and age hardening in commercial dental gold alloys have mainly focused on pseudobinary (AuCu) 1Àx -Pt x alloys [19][20][21][22][23][24].…”

Solid state transformations of Au-Cu-Pt alloys studied by in-situ X-ray synchrotron radiation and DSC

“…Various methods have been used to this end; these include differential thermal analysis (DTA) or differential scanning calorimetry (DSC) [6e11], resistometry [8,12,13], dilatometry [11,14,15] and in situ X-ray diffraction [6,11,16e18]. Whereas the former three methods are typically conducted dynamically (data being collected while heating or cooling the alloy), most studies of ordering or disordering using X-ray diffraction are isothermal [16e19].…”