Oxygen and Nitrogen Uptake in Dental Ni-Cr Alloy Castings by Several Melting Methods

Abstract

Oxygen and nitrogen introduced in three Ni-Cr alloy castings were significantly varied according to both different alloys and different melting methods. The arc melting in Ar blow caused significant increases in the amounts of oxygen and nitrogen uptake, which were influenced by alloy composition. The severe gas absorption by the arc melting in Ar blow resulted in the marked occurrence of porosity in the castings of the alloy containing lesser amounts of Cr, Si and/or Mn. No significant variations in hardness of the castings were found due to the differences in melting methods.