A Certificate of Analysis (CoA) is the document a MIM supplier issues with each shipment, certifying that the parts meet the specified material and dimensional requirements. It is not the same as a Certificate of Conformance (CoC), which only states conformance without providing actual test data.
What a complete MIM CoA should include:| Data Category | Specific Parameters | Why It Matters |
|---|---|---|
| Material identification | Grade, specification (ASTM/MPIF), powder lot number | Confirms you got the correct alloy |
| Chemical composition | Full elemental analysis (C, Cr, Ni, Mo, Si, Mn, P, S, etc.) | Verifies material meets the grade standard |
| Powder characteristics | PSD (D10/D50/D90), apparent density, Hall flow | Confirms powder quality for future batches |
| Mechanical properties | UTS, yield strength, elongation, hardness | Verifies sintering quality and heat treatment |
| Density | Sintered density (g/cm³), % of theoretical | Confirms sintering process was correct |
| Dimensional results | Summary of critical dimensions measured, Cpk values | Shows dimensional capability for the batch |
| Quantity | Number of parts in the shipment | Inventory verification |
| Document | Contains Actual Test Data? | Certifies Conformance? | Typical Use |
|---|---|---|---|
| Certificate of Analysis (CoA) | Yes — includes specific measured values | Yes | Standard for MIM material certification |
| Certificate of Conformance (CoC) | No — states "parts conform to specification" | Yes | Acceptable for non-critical applications |
A proper MIM CoA should include: material identification and powder lot number, full chemical composition, powder PSD (D10/D50/D90), sintered density, mechanical properties (UTS, yield, elongation, hardness), dimensional inspection summary, and Cpk values for critical features. Always request the CoA, not just a CoC — the actual test data is the only way to verify that your parts meet the material specification.