Meaning
Structural defect characterized by the formation of microscopic voids near the interface of two diffusing metals arises from unequal atomic transport rates. This Kirkendall porosity weakens the mechanical strength of joint zones in heat exchangers and microelectronics. The State Administration for Market Regulation (SAMR) enforces GB/T standards to limit these interface defects in manufacturing.
It represents one of the most critical structural checks during the auditing of high-reliability electronic assemblies.
Defect Formation
Unequal diffusion rates between different atomic species produce a net flux of vacancies toward the faster-diffusing side. When vacancies accumulate and coalesce, Kirkendall porosity develops, initiating micro-cracks along the welded interface. These voids reduce the shear strength of critical load-bearing components.
Regulatory Inspection
Testing laboratories accredited by CNAS utilize scanning electron microscopy to detect these interface voids in industrial samples. Regulatory standards dictate the maximum permissible area fraction of voids in welded joints. Companies whose products exceed these limits must revise their manufacturing processes to achieve compliance.
Operational Limit
Joints showing significant void density are rejected during GACC import clearance or local factory inspections. Foreign contractors must provide proof of high-vacuum or pressure-assisted heat treatment to minimize vacancy accumulation. Meeting these structural criteria is mandatory for supply chain approval.
