leometwu的部落格

200 x, 200x, 1000x  at 12x8 cm;  經鏡面拋光的不銹鋼塑膠射出成形模具(大立光電的), 粒界腐蝕源自冷卻水孔, 致使昂貴的模具夭壽.  Micrograph of a prematurely failed plastic injection tooling made of stainless steel. Grainboundary corrosion cracks initiated from inner wall of cooling conduits. Multiple, branched cracks is usually SCC----Stress Corrosion Cracking.

下面是 Dark Field  照片. 突顯 Chrome carbide at grainboundary. 
 
 
 
  

聚成碳化鉻的鉻是從周圍基地"抽取"出來的, 因此碳化鉻附近成為"貧鉻區(<12%)"-----易受腐蝕.