Cu2O (Cuprous Oxide)

Notas

Cuprous oxide (Cu2O) serves as a primary coloring agent in ceramic glazes, prized specifically for its ability to produce rich red tones through reduction firing. The transformation from cupric oxide (CuO) to cuprous oxide is achieved via a reduction process where carbon monoxide facilitates the chemical change. When utilized in small quantities, typically around 0.5%, it yields vibrant red hues. Higher concentrations promote the formation of colloidal copper particles within the molten glass, resulting in deep, saturated effects such as sang-de-boeuf or flambé. Because this oxide is susceptible to volatilization at elevated temperatures, careful management of kiln atmosphere is required to prevent unintended coloration of adjacent ware. Beyond color development, Cu2O is employed in low-temperature decorative techniques to create metallic copper lusters. This specific process involves firing at approximately 950°C followed by a cycle of heavy reduction during cooling, often achieved by introducing combustible materials. This technique typically requires a higher oxide concentration of 2% to 8%. Structurally, this inorganic compound is naturally occurring as the mineral cuprite and can manifest in yellow or red colors depending on particle size, while its electronic properties as a semiconductor have led to various industrial applications outside of the ceramics studio.