Liquid Nitriding / QPQ
QPQ — also known as Salt Bath Ferritic Nitrocarburising — is a multi-stage surface treatment process involving nitrocarburising in a molten salt bath, followed by oxidising, polishing, and re-oxidising. The process delivers a compound layer with exceptional corrosion resistance, low surface roughness, and improved wear resistance, all while maintaining tight dimensional tolerances on finished components.
Our precision advantage
QPQ achieves a superior combination of corrosion protection and a near-mirror surface finish in a single integrated process cycle — making it ideal for components requiring both tribological performance and aesthetic quality, such as hydraulic rods, automotive trim parts, and firearm components.
Why choose Liquid Nitriding / QPQ?
Superior corrosion resistance
Outperforms conventional nitriding and many plating processes in salt spray testing
Low surface roughness
Polishing stage delivers a smooth, aesthetically pleasing finish
Wear resistance
Hard compound layer resists adhesive and abrasive wear
Minimal distortion
Low processing temperature preserves precision geometry
Process specifications
| Process | Salt bath nitrocarburising + oxidise + polish + re-oxidise |
| Key properties | Corrosion resistance, Low friction, Wear resistance |
Industries served
- Automobile
- Defence
- Oil & Gas
- General Engineering