Chromic Acid (20%) vs HDPE Compatibility
Verified chemical resistance rating (Acceptable with Operating Controls), thermal boundary limits (Ambient service (72°F / 22°C) preferred; monitor wear in continuous service), and material specification guide for HDPE exposed to Chromic Acid (20%) in Strong Oxidizing / Mineral Acid service.
Chromic Acid (20%) vs HDPE: B-Good
Exposing HDPE to Chromic Acid (20%) (Formula: H2CrO4 / CrO3 (20% aq.), CAS: 7738-94-5) carries an official rating of B-Good (Acceptable with Operating Controls). Maximum recommended thermal operating limit: Ambient service (72°F / 22°C) preferred; monitor wear in continuous service. Best Grade A alternative materials for continuous or high-temperature service: Viton, PTFE, PVDF.
Technical Specifications and Operating Parameters
| Chemical Medium | Chromic Acid (20%) |
|---|---|
| Chemical Formula | H2CrO4 / CrO3 (20% aq.) |
| CAS Registry Number | 7738-94-5 |
| Chemical Functional Class | Strong Oxidizing / Mineral Acid |
| Wetted Material | HDPE |
| Official Resistance Rating | B-Good (Grade B) |
| Engineering Service Verdict | Acceptable with Operating Controls |
| Max Temp and Concentration Limit | Ambient service (72°F / 22°C) preferred; monitor wear in continuous service |
| Best Grade A Alternatives | Viton, PTFE, PVDF |
| Backtest and Audit Verification | Verified against Cole-Parmer, ISM, Graco & CP Lab Safety industrial chemical resistance charts. |
Chromic Acid (20%) Cross-Material Comparison Matrix (9 Materials)
Direct benchmark ratings across all 9 reference industrial materials for Chromic Acid (20%):
| Material Name | Compatibility Rating | Service Verdict | Temperature Limit | Datasheet |
|---|---|---|---|---|
| Buna-N | D-Severe Effect | Incompatible — Immediate Failure Risk | Not recommended at any temperature or concentration | Report |
| EPDM | C-Fair | Caution: Limited / Intermittent Service Only | Ambient intermittent contact only; do not pressurize | Report |
| HDPE | B-Good | Acceptable with Operating Controls | Ambient service (72°F / 22°C) preferred; monitor wear in continuous service | Report |
| Polypropylene | C1-Fair | Caution: Short-Term or Emergency Use Only | Short-term exposure only; avoid continuous pressurized service | Report |
| PTFE | A-Excellent | Safe for Continuous Industrial Service | Ambient to elevated operating temperatures within standard material limits | Report |
| PVC | B-Good | Acceptable with Operating Controls | Ambient service (72°F / 22°C) preferred; monitor wear in continuous service | Report |
| PVDF | A1-Excellent | Safe for Continuous Industrial Service | Up to 120°F (49°C) verified; up to material thermal limit in non-pressurized service | Report |
| Stainless Steel | B1-Good | Acceptable with Routine Inspection | Up to 120°F (49°C) with minor absorption/corrosion allowance | Report |
| Viton | A-Excellent | Safe for Continuous Industrial Service | Ambient to elevated operating temperatures within standard material limits | Report |
Chemical and Material Interaction Analysis
Engineering Compatibility Verdict
Chromic Acid (20%) vs HDPE: B – Good (Minor Effect / Conditional)
Summary Verdict: HDPE (High-Density Polyethylene) is rated B-Good (Acceptable with Operating Controls) when exposed to Chromic Acid (20%) (Formula: H2CrO4 / CrO3 (20% aq.), CAS: 7738-94-5). Acceptable for low-pressure piping, static seals, and scheduled-maintenance components. Implement periodic visual and dimensional inspection.
Quick Engineering Specifications
| Chemical Media | Chromic Acid (20%) |
|---|---|
| Chemical Formula | H2CrO4 / CrO3 (20% aq.) |
| CAS Registry Number | 7738-94-5 |
| Chemical Classification | Strong Oxidizing / Mineral Acid |
| Wetted Material | HDPE (High-Density Polyethylene) (Linear Semi-Crystalline Polyolefin Thermoplastic) |
| Official Resistance Rating | B – Good (Minor Effect / Conditional) (Grade B) |
| Recommended Temperature Window | Ambient service (72°F / 22°C) preferred; monitor wear in continuous service (Material limit: -60°F to 140°F (-51°C to 60°C)) |
| Top Grade-A Alternatives | Viton, PTFE, PVDF |
| Data Verification Status | Verified against Cole-Parmer, ISM, Graco & CP Lab Safety industrial chemical resistance charts. |
Chemical & Material Interaction Analysis
Chromic Acid (20%) is classified as a strong oxidizing / mineral acid (corrosive proton attack combined with strong oxidative potential). Used in chemical synthesis, metal pickling, pH neutralization, and industrial etching. When selecting wetted components for HDPE, engineers must account for both concentration-dependent chemical attack and thermal stress:
- Reaction & Failure Mechanism: Exhibits minor chemical interaction—such as slight discoloration, mild dimensional swell, or slow uniform surface etching—that does not immediately compromise structural integrity.
- Material Profile (HDPE): High impact strength (even at sub-zero temperatures) and excellent resistance to mineral acids, caustics, salt brines, and alcohols. However, lower upper temperature limit (140°F/60°C) than Polypropylene, with susceptibility to permeation and environmental stress cracking in aromatic/chlorinated hydrocarbons and strong oxidizers.
- Application Scope: Common wetted components include bulk chemical storage tanks, IBC totes, double-containment underground piping, and chemical drum liners.
Cross-Material Compatibility Comparison for Chromic Acid (20%)
To help you select the longest-lasting piping, valve lining, or O-ring seal for Chromic Acid (20%), the table below compares HDPE against 8 other common industrial engineering materials:
| Wetted Material | Compatibility Rating | Service Recommendation | Material Temp Range |
|---|---|---|---|
| Polypropylene (PP Homopolymer & Copolymer) | C1-Fair | Caution: Short-Term or Emergency Use Only | 32°F to 180°F (0°C to 82°C) |
| 316 / 304 Austenitic Stainless Steel | B1-Good | Acceptable with Routine Inspection | -325°F to 800°F (-198°C to 426°C) |
| Viton® (FKM Fluoroelastomer) | A-Excellent | Safe for Continuous Industrial Service | -15°F to 400°F (-26°C to 204°C) |
| PTFE (Teflon® / Polytetrafluoroethylene) | A-Excellent | Safe for Continuous Industrial Service | -328°F to 500°F (-200°C to 260°C) |
| EPDM (Ethylene Propylene Diene Monomer) | C-Fair | Caution: Limited / Intermittent Service Only | -60°F to 300°F (-51°C to 149°C) |
| PVC Type I (Unplasticized Polyvinyl Chloride / uPVC) | B-Good | Acceptable with Operating Controls | 32°F to 140°F (0°C to 60°C) |
| PVDF (Kynar® / Polyvinylidene Fluoride) | A1-Excellent | Safe for Continuous Industrial Service | -40°F to 280°F (-40°C to 138°C) |
| Buna-N (Nitrile / NBR Elastomer) | D-Severe Effect | Incompatible — Immediate Failure Risk | -40°F to 250°F (-40°C to 121°C) |
| HDPE (High-Density Polyethylene) (Current Page) | B-Good | Acceptable with Operating Controls | -60°F to 140°F (-51°C to 60°C) |
Frequently Asked Questions (FAQ)
Is HDPE compatible with Chromic Acid (20%)?
HDPE is rated B-Good (Acceptable with Operating Controls) with Chromic Acid (20%) (Formula: H2CrO4 / CrO3 (20% aq.), CAS: 7738-94-5). Exhibits minor chemical interaction—such as slight discoloration, mild dimensional swell, or slow uniform surface etching—that does not immediately compromise structural integrity. Acceptable for low-pressure piping, static seals, and scheduled-maintenance components. Implement periodic visual and dimensional inspection.
What is the best alternative material for handling Chromic Acid (20%)?
If HDPE does not meet your temperature or pressure requirements for Chromic Acid (20%), the highest-rated Grade A alternatives are Viton, PTFE, PVDF. Always verify O-ring elastomers and metallic fasteners separately before full-scale deployment.
Technical Engineering FAQs: Chromic Acid (20%) vs HDPE
Click any question below for chemical failure-mode specifics, thermal derating limits, and material selection rules: