Why chromite powder 325F pigment can make green color glass?
Chromite powder 325F pigment is an effective colorant for making green color glass containers and plates. The coloring mechanism of chromite powder (325F, 200F, 400F, etc.) of glass coloring pigment is mainly based on the optical properties of chromium ions (Cr³⁺). The details are as follows:
1. The presence of chromium ions: The chromium in chromite powder exists in the form of Cr³⁺, and these ions are evenly distributed in the glass matrix.
2. d-d electron transition: The 3d electrons of Cr³⁺ transition under the action of the crystal field, absorbing visible light of a specific wavelength, causing the glass to appear green.
3. Crystal field effect: The crystal field strength in the glass matrix determines the d orbital energy level splitting of Cr³⁺, which in turn affects the absorption spectrum and color.
4. Concentration effect: The higher the concentration of Cr³⁺, the stronger the light absorption and the darker the color.
5. Redox environment: The redox conditions during glass melting will affect the valence state of chromium, thereby changing the color. Under oxidizing conditions, Cr³⁺ is green, and under reducing conditions, Cr²⁺ is blue.
The main component of chromite powder is Cr2O3, which is mainly trivalent chromium. It comes from natural chromium ore and does not need to be produced through chemical production like chromium oxide green, so it has good economic benefits.
