Passivate Clear [QQ-P-35, or ASTM]  

Passivate Clear QQ-P-35 is a chemical treatment process used to enhance the corrosion resistance of stainless-steel surfaces. This process involves removing free iron and other contaminants from the surface, creating a passive oxide layer that protects against rust and corrosion. Ideal for aerospace, medical, and industrial applications, Passivate Clear ensures the longevity and durability of stainless components while maintaining their clean, clear appearance.

QQ-P-35 was an earlier standard for “passivation treatments for corrosion-resistant steel.” It was first issued by the U.S. Department of Defense in July 1963, with the aim of standardizing component passivation procedures for existing providers, primarily in the aerospace industry. We now reference the ASTM standard.

 Purpose: QQ-P-35 focused on passivation treatments for stainless steel parts to enhance their corrosion resistance.

• Methods: The standard outlined various passivation techniques, primarily using nitric acid / sodium dichromate. Different methods were specified based on the type of stainless steel being treated.
• Types: QQ-P-35 initially had eight processes, but Types I, III, IV, and V were eventually withdrawn. The remaining four types had varying combinations of process time, temperature, and acid concentration.
• Transition: In 1998, QQ-P-35 was withdrawn and replaced by ASTM A967 and AMS-QQ-P-35. ASTM A967 was already an existing standard, while AMS-QQ-P-35 was a republishing of the same standard under the auspices of the Society of Automotive Engineers (SAE).
• Citric Acid Addition: Unlike QQ-P-35, both ASTM A967 and AMS 2700 introduced citric acid (C ₆H ₈O ₇) as a passivation chemical, alongside nitric acid. This addition improved the passivation process.

If you encounter references to QQ-P-35, it’s important to recognize that ASTM A967 and AMS 2700 are the current replacement standards for passivation treatments when QQ-P-35 is requested.

These newer standards provide updated guidelines and incorporate citric acid for improved passivation results. If you have questions, please call us today.