Rating
| Concentration | 20 °C | 50 °C | Remark |
|---|---|---|---|
| 1 % | D* | – | |
| 30 % | D | D | |
| 45 % | D | D | |
| 50 % | D | D | |
| 60 % | D | D | |
| concentrated | D | D |
* estimated rating, given in the source without a temperature
Material comparison at 20 °C
Resistance overview
Aluminium maintains a consistent rating of D across all 6 tested concentrations (1 %, 30 %, 45 %, 50 %, 60 %, concentrated) of Sodium Hydroxide (Caustic Soda) at 20 °C. The fact that the rating does not change with concentration within the tested range simplifies material selection, though the boundary conditions beyond this range remain untested. The rating remains stable between 20 °C and 50 °C, which means this material can also handle moderately elevated process temperatures without additional risk.
Application context
Sodium Hydroxide (Caustic Soda) is commonly encountered in water treatment and textile processing. Aluminium (Aluminium) is a metal typically used for vessels, heat exchangers, fittings and structural components. Because Sodium Hydroxide (Caustic Soda) is classified as corrosive, the choice of containment material is especially critical to prevent leaks, equipment damage, and safety hazards.
Practical recommendation
Aluminium is not recommended for use with Sodium Hydroxide (Caustic Soda). The D rating indicates that the material will suffer rapid and severe degradation, which may include cracking, dissolution, severe swelling, or complete structural failure. Using this combination risks equipment damage, leaks, and potential safety incidents. Consider using HDPE, LDPE, Nylon (PA) instead, which are rated A for this chemical and offer reliable long-term performance.
Did you know?
In industrial practice, Aluminium components exposed to Sodium Hydroxide (Caustic Soda) are typically inspected for swelling, discoloration, or loss of mechanical strength as early indicators of chemical attack.
Materials rated A or B at 20 °C
Based on the row for 60 %, 20 °C.
- Thermoplastics
- HDPE A, PP A, LDPE A, Nylon (PA) A, Polystyrene A, Polysulfone A, PMP A
- Fluoropolymers
- PTFE A
- Elastomers
- EPDM A, NBR B
- Metals
- SS 316 A, SS 304 A
About Aluminium
Aluminium relies on a thin oxide layer. Strong acids, strong alkalis and mercury compounds destroy that layer.
Rating scale
- A very good resistance
- B good resistance
- C limited resistance
- D not resistant
- – no data
- K no general statement possible
A rating marked * is an estimate in the source, not a test result. An estimate is given as one value without a temperature.
About this data
The ratings come from the chemical resistance list published by Bürkle GmbH, which compiled them from raw-material manufacturers’ data. They describe laboratory tests on the raw material at 20 °C and 50 °C.
A finished part also sees pressure, mechanical stress, welds and mixtures that a laboratory test does not. Treat the rating as a first filter and test under your own conditions before relying on it.