COA vs COC for Titanium Parts
Neutral guide to the difference between Certificate of Analysis and Certificate of Compliance in titanium procurement.
Quick Answer
A Certificate of Analysis (COA) documents the measured chemical composition, while a Certificate of Compliance (COC) declares that material conforms to a specification. A Mill Test Report is more comprehensive and is often preferred.
Checklist
- Confirm whether your requirement needs composition data (COA) or a conformance statement (COC)
- Check whether an MTR is expected instead
- Verify the document references the correct grade and standard
- Confirm traceability to the heat or lot
Know which certificate you asked for
The right document depends on what you must verify: composition, conformance, or full test data.
KEEP THE GAP
Definitions and requirements follow the governing standard and your quality system. titanium.blog does not issue certifications.