Research on the preservation status evaluation system of calcium glaze porcelain exposed to the ocean

Abstract To address the problem that the current assessment of the preservation condition of marine calcium glaze porcelain mainly relies on visual and qualitative analysis, this article takes the calcium glaze porcelain from the “Nanhai I” and “Huaguangjiao No.1” shipwrecks as the research objects. By integrating multiple analytical techniques, it establishes a scientific and efficient evaluation system. Based on test data and microscopic morphological analysis, samples are categorized into four preservation condition grades: A, B, C, and D. This classification defines the physical parameter ranges and core morphological characteristics for each category, establishing a comprehensive evaluation method of “initial physical parameter assessment + microscopic feature verification” to effectively overcome the limitations of single-parameter evaluation. The study revealed that the scratch hardness of surfaces on the body can rapidly distinguish severely degraded specimens, while the presence of through-cracks and sediment diffusion patterns serves as key indicators for classifying intermediate degradation levels.