Rating
| Concentration | 20 °C | 50 °C | Remark |
|---|---|---|---|
| 10 % | A | A | |
| 20 % | – | – | |
| 50 % | C | D |
Material comparison at 20 °C
Resistance overview
The resistance of HDPE to Chromic Acid is concentration-dependent. Across the 2 tested concentrations (10 %, 50 %), the 20 °C rating ranges from A at lower concentrations to D at higher ones. This means engineers must verify which concentration their process actually involves before relying on a single rating. However, at 50 °C the resistance rating drops, indicating that temperature must be factored into the design. For heated applications, additional testing under actual service conditions is strongly recommended.
Application context
Chromic Acid is commonly encountered in laboratory work and surface cleaning. HDPE (High-density polyethylene) is a thermoplastic typically used for tanks, piping, containers and liners. Because Chromic Acid is classified as corrosive, the choice of containment material is especially critical to prevent leaks, equipment damage, and safety hazards.
Practical recommendation
HDPE has limited resistance to Chromic Acid and should only be used for short-term or intermittent contact at ambient temperature. The C rating means the material undergoes noticeable changes — swelling, loss of strength, or surface degradation — that make it unsuitable for permanent installations. For prolonged or continuous exposure, PVC Rigid, PVC Flexible, ECTFE/ETFE offer significantly better resistance and are rated A.
Did you know?
When choosing between thermoplastics for Chromic Acid service, engineers consider not just the resistance rating but also factors such as permeation rate, creep resistance, and weldability.
Materials rated A or B at 20 °C
Based on the row for 50 %, 20 °C.
- Thermoplastics
- PVC Rigid A, PVC Flexible A, PMP B
- Fluoropolymers
- PTFE A, PVDF A, FEP A, ECTFE/ETFE A
- Elastomers
- Viton (FPM) A
- Metals
- SS 316 B, SS 304 B
About HDPE
High-density polyethylene resists most aqueous acids, alkalis and salt solutions. Strong oxidising acids, chlorinated solvents and aromatic hydrocarbons attack or swell it. Continuous service is usually limited to about 80 °C.
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.