SURFACE FINISHES COMPARED
ENIG or hard gold: which PCB surface finish?
The catalogue publishes the same cost, flatness and shelf life for ENIG and hard gold; the table below shows where they differ.
- Known risk with ENIG: Black pad.
- Known risk with hard gold: Cost/selective.
ENIG and hard gold, as published
| Property | ENIG | Hard gold |
|---|---|---|
| Cost, USD per square inch | 0.10–0.20 | Variable |
| Shelf life | 12+ mo | 12+ mo |
| Reflow passes | 5+ | not published |
| Minimum pitch, mm | 0.4 | not published |
| RF performance | Poor (Ni loss) | not published |
| Gold wire bonding | No | No (soft only) |
| Aluminium wire bonding | Yes | No |
| Standard | IPC-4552B | MIL-G-45204 |
| Known risk | Black pad | Cost/selective |
How this was counted
Both columns come from the surface finish table in the MPBxChange material catalogue, as its sources published them. Costs are indicative ranges in US dollars per square inch, not quotations, and move with the gold price and the fabricator. "Not published" means the source gave no value, not that the answer is no.