Analysis of the Causes of Chromatic Aberration in AlN Substrate Ceramics

Aluminum Nitride Ceramic Substrate

The causes of color difference in AlN ceramics are related to raw material preparation, processing technology (sintering temperature fluctuation, protective atmosphere), microstructure, and environmental factors. The following provides a comprehensive analysis based on related research:

1. Surface Color Change Due to Oxidation Behavior

AlN ceramics easily react with oxygen at high temperatures to form aluminum oxide (Al₂O₃). The thickness and structure of the oxide layer significantly affect the surface color.

Oxidation kinetics: Differential thermal analysis shows that the mass change of AlN during variable temperature oxidation is related to the degree of oxidation. Different stages of the oxidation reaction may be accompanied by gradual changes in color.

2. Influence of Preparation Process and Raw Material Purity

Difference in synthesis methods: The hydrothermal–carbothermal synthesis method can reduce impurity introduction by regulating precursor homogeneity (e.g., γ-AlOOH@C core–shell structure). However, if the raw materials (e.g., aluminum nitrate, sucrose) are of insufficient purity, residual impurities (e.g., Fe, Si) will alter the color properties of the ceramics.