Temperature Effects on the Dimensions of CoCr Alloys: Dilatometric Study

Résumé

Cobalt-chromium (Co-Cr) alloys are widely employed in biomedical and dental applications due to their favourable mechanical properties, corrosion resistance, and thermal stability. This study investigates the effect of silicon (Si) addition on the chemical composition and dimensional behavior of Co-Cr alloys, with an emphasis on their suitability for removable partial denture frameworks. A series of Co-Cr alloys with variable Si content (0.5–7.05 wt.%) were analysed using optical emission spectrometry and dilatometry to establish correlations between composition and thermal expansion.
The experimental approach provides new insights into how silicon content modifies the thermal behavior and dimensional stability of Co-Cr alloys during heating up to 1200 °C. The novelty of this research lies in the systematic evaluation of Si addition as a compositional variable in Co-Cr dental alloys, which has not been extensively explored in relation to dilatometric behavior. The study demonstrates that controlled silicon enrichment not only reduces the linear thermal expansion coefficient but also enhances structural stability during thermal cycling, minimizing the risk of deformation or mismatch with low-fusing dental ceramics. These findings bridge the gap between alloy chemistry and thermal compatibility, offering a scientific basis for optimizing alloy formulations used in precision dental restorations.

The outcomes provide valuable guidelines for the development of advanced Co-Cr-Si alloys with improved dimensional accuracy and thermal performance, contributing to the reliability and longevity of metal-ceramic prosthetic components.