Elemental release from CoCr and NiCr alloys containing palladium

Area of Science:

• Materials Science
• Biomaterials Engineering
• Corrosion Science

Background:

• New palladium-containing casting alloys (CoPdCr, NiPdCr) have been developed by incorporating palladium (approx. 25 wt%) into traditional base metal alloys.
• Evaluating the elemental release and corrosion behavior of these novel alloys is crucial for their clinical application.

Purpose of the Study:

• To assess the elemental release of new CoPdCr and NiPdCr casting alloys.
• To compare the elemental release of these new alloys against traditional CoCr and NiCr alloys.

Main Methods:

• Five casting alloys were tested: CoPdCr-A, CoPdCr-I, NiPdCr, CoCr, and NiCr.
• Specimens were immersed in a lactic acid/NaCl solution at 37°C for 7 days (ISO 10271).
• Elemental release was quantified using ICP-AES, and corrosion was examined via optical microscopy.

Main Results:

• CoPdCr alloys exhibited significantly higher release of cobalt, chromium, molybdenum, and total ions compared to traditional CoCr.
• No significant difference in elemental release was found between NiPdCr and NiCr alloys.
• Optical microscopy revealed substantial corrosion in palladium-containing CoCr alloys post-immersion.

Conclusions:

• Alloying CoCr with palladium compromises corrosion resistance, indicated by increased elemental release.
• Palladium addition did not negatively impact the corrosion resistance of NiCr alloys.
• The findings suggest that palladium's effect on corrosion varies between CoCr and NiCr base alloys.