Niello Cracking & Flaking

乌银开裂与脱落

type:troubleshooting · level:intermediate · material:silver · variant:sulfide · scale:jewellery · equipment:furnace · stage:patina

标签：故障,开裂,脱落,硫比例,冷却

乌银开裂多因冷却过快或配比中硫过多导致脆性增大；脱落常因沟槽过浅或表面有油污。解决：降低硫比例、放慢冷却、镶嵌前用硼砂水彻底除油并加深沟槽。

Niello cracks mainly from too-rapid cooling or excess sulfur making it brittle; flaking usually means grooves are too shallow or greasy. Fix by reducing sulfur, cooling slowly, degreasing with borax water before setting, and deepening the grooves. ---