# Knitted Nickel Mesh

*Single jersey / Interlock double-knit*

The standard PTL between bipolar plate and electrode in alkaline stacks. Single jersey (660-850 g/m², 90-98% porosity) for small-area stacks under 10 bar clamping — elastic enough to follow plate surface irregularities. Interlock (850-1,150 g/m², 85-92% porosity) for stacks over 0.8 m² where crush resistance matters. In 2019, a German field trial returned six stacks with PTL compression-set failure — single jersey had work-hardened after 5 years of thermal cycling, losing 40% thickness. We switched that customer to interlock. No failures since. Wire is always Ni201 — the knit has ~12,000 contact points per m², each a potential corrosion site with standard Ni200. Every roll ships with compression-recovery data at 5/10/15 bar, EN 10204 3.1 cert, ISO 9044 and ASTM B456.

## Technical specifications

| Parameter | Value |
|---|---|
| Alloy grades | Ni200 (UNS N02200), Ni201 (UNS N02201), N6 (Chinese GB) |
| Knit structure | Single jersey (single-bed) / Interlock (double-bed) |
| Wire diameter | 0.16 - 0.19 mm |
| Packing density | 660 - 1150 g/m² (customizable to target compression) |
| Porosity | 85 - 98 % volumetric (tunable via wire diameter and knit tension) |
| Corrugation depth | Up to 8 mm (enhances electrolyte mixing) |
| Compression recovery | Elastic spring-back; detailed recovery data on request |
| Roll width | Standard 1000; max 2700; custom slitting available mm |
| Nickel purity | Min 99.5% (Ni200/N6), min 99.0% (Ni201 low-carbon) |
| Applicable standards | ASTM B456, ISO 9044, ISO 4783 |

## Technical specifications

## FAQ

### What knitted nickel mesh specification works as a porous transport layer (PTL)?

Single jersey at 660-850 g/m² with 90-98% porosity suits small-area stacks under 10 bar clamping. For stacks above 0.8 m², specify interlock at 850-1,150 g/m² with 85-92% porosity for crush resistance. Wire is always Ni201, 0.16-0.19 mm diameter.

### Woven or knitted nickel mesh for my electrolyzer - which one?

Use woven mesh where a rigid, uniform-aperture substrate is needed, such as catalyst coating support. Use knitted mesh as the compressible PTL between bipolar plate and electrode: its 3D loop structure acts as an elastic spring under 5-15 bar clamping force and recovers when released.

### How do you prevent compression-set failure in PTL mesh?

Single jersey can work-harden after years of thermal cycling - in one 2019 field trial it lost 40% thickness after 5 years. We switched that customer to interlock knit and there have been no failures since. Compression-recovery data at 5/10/15 bar is available with the technical report.

### Why is Ni201 mandatory for knitted PTL mesh?

The knit structure has roughly 12,000 wire contact points per m², each a potential corrosion site. Ni200's carbon content (0.15% max) forms grain-boundary carbides that hot KOH attacks; Ni201 (0.02% C max) removes that failure path and supports 60,000+ hour stack lifetimes.