Anodizing Bicycle Spokes in Hot Sodium Hydroxide

Sara Franco, Eric Galindo, and T. David Burleigh

New Mexico Institute of Mining and Technology

Anodizing steel in hot 50% sodium hydroxide at varying temperatures, voltages, and times was done in order to produce different oxide colors across the surface of the wire. The objective is to understand the relationship between the color and the anodizing variables such as current, density, and temperature. B42 bicycle spokes are a difficult to anodize due to being made of high carbon steel. Other trials produced a range of brown colors across the wire. The goal was to achieve an understanding why the spokes had a large range of brown colors instead of producing the dichroic colors seen in 1010 steel. These tests were done by attaching the B42 anode and a steel cathode to the voltage source and placing both in a 400 mL beaker of hot 50% sodium hydroxide.