Cr-Based Sputtered Decorative Coatings for Automotive Industry

Area of Science:

• Materials Science
• Surface Engineering
• Tribology

Background:

• Automotive parts metallization traditionally uses toxic hexavalent chromium.
• Developing environmentally friendly alternatives is crucial for the automotive industry.
• Polycarbonate (PC) is a lightweight plastic suitable for automotive components.

Purpose of the Study:

• To investigate the effects of oxygen (O) and nitrogen (N) on chromium (Cr) sputtered coatings deposited on polycarbonate (PC).
• To evaluate these coatings as a viable, non-toxic alternative for automotive part metallization.
• To understand how O and N influence the structural, mechanical, and optical properties of Cr-based coatings.

Main Methods:

• DC magnetron sputtering of a pure Cr target in a reactive atmosphere (N2 and/or O2).
• Controlled deposition pressure (approx. 1 Pa) and target current density (20 mA·cm-2).
• Structural characterization (identifying crystalline phases and amorphous oxides) and hardness testing.

Main Results:

• Coatings comprised mixtures of α-Cr, δ-Cr, β-Cr2N, and CrN crystalline structures, alongside amorphous oxides.
• Coating hardness varied from 9 GPa (CrON) to 15 GPa (CrN).
• Excellent interface adhesion was observed, with tunable optical properties achieved by adjusting O and N content.

Conclusions:

• Sputtered Cr-based coatings offer a promising, non-toxic alternative for automotive part metallization.
• The ability to tune properties through O and N addition allows for tailored applications.
• These findings support the potential industrialization of these coatings in the automotive sector.