What is the name of the nonelectrolytic chemical treatment for aluminum alloys that enhances corrosion resistance and paint-bonding qualities?

The process you're referring to, which enhances corrosion resistance and paint-bonding qualities for aluminum alloys, is indeed known as Alodizing. This is a type of chemical conversion coating that provides a protective layer on aluminum, improving its surface characteristics. Alodizing is particularly beneficial because it creates a non-metallic layer that adheres well to the base metal, providing excellent adhesion for paint and ensuring long-lasting protection against corrosion.

While there are other treatments like chromating and anodizing, Alodizing specifically offers a nonelectrolytic approach, distinguishing it from anodizing, which relies on an electrochemical process to create a thicker protective oxide layer. Chromating also provides corrosion resistance but is generally not used for enhancing paint adhesion to the same extent as Alodizing. Phosphate coating offers benefits primarily for ferrous metals rather than aluminum.

Thus, Alodizing stands out as the preferred method for improving the surface properties of aluminum alloys in applications where enhanced corrosion resistance and paint adhesion are critical.