Which check valve is superior, a 17YBCVNL Brass vs. 17CVNL Bronze?

Bronze is by far the superior product!

Bronze alloys are significantly higher in cost due to the high copper content. However, it can be worth every penny to install bronze, as it is not susceptible to dezincification and has far superior corrosion resistance. It is not suggested to install a brass valve in a submersible pump column or in systems with aggressive water conditions. The brass valves will perform well in areas with nonaggressive water and are suitable for applications where change out is not a costly endeavor in the event the valve does get affected by dezincification. The only benefit of brass over bronze is the lower cost.

17YBCVNL Brass (Yellow Brass)                                                         

• Brass is the generic term for a range of copper-zinc alloys. The copper (Cu) range is 58 to 64 % and the zinc (Zn) range is 32 to 38%.          
• Good corrosion resistance.                                                                                
• Brass alloys contain more than 15% Zn and therefore are susceptible to dezincification.              

17CVNL Bronze (Red Brass)              

• Bronzes are a family of high copper content material and contain less than 15% Zn. The Cu range is 81 to 86 % and the Zn range is 7 to 10%.   
• Excellent corrosion resistance (including against saltwater).                     
• Bronze alloys contain higher copper content, hence the name Red Brass, with 15% or less zinc content. This makes the alloys practically immune to dezincification.      

 Additional Resources

https://hghouston.com/archive/material-property-data/copper-and-copper-alloys/brasses/dezincification