| HS Code | 574932 |
| Chemical Composition | Aqueous solution of fluorosurfactant and non-ionic wetting agents |
| Appearance | Clear to slightly amber liquid |
| Odor | Mild, characteristic surfactant odor |
| Solubility In Water | Completely miscible |
| Ph 1 Percent Solution | 7.0 - 9.0 |
| Specific Gravity At 20c | 1.00 - 1.10 |
| Boiling Point | Approximately 100°C (212°F) |
| Freezing Point | Approximately 0°C (32°F) |
| Flash Point | Greater than 93°C (200°F), non-flammable |
| Vapor Pressure At 20c | 23 hPa (approximately 17 mmHg) (water-based) |
| Evaporation Rate | Less than 1 (compared to butyl acetate = 1), slow |
| Stability | Stable under normal storage and handling conditions |
| Reactivity | No hazardous polymerization |
| Incompatibility | Strong oxidizing agents |
| Hazardous Decomposition Products | Carbon monoxide, carbon dioxide, hydrogen fluoride under combustion |
| Storage Temperature | 5°C to 40°C (41°F to 104°F) |
As an accredited Chromium Fog Inhibitor factory, we enforce strict quality protocols—every batch undergoes rigorous testing to ensure consistent efficacy and safety standards.
| Packing | Chromium Fog Inhibitor is supplied in a durable 5-gallon pail with resealable lid, ensuring safe storage, easy handling, and controlled dispensing. |
| Container Loading (20′ FCL) | 20′ FCL: sealed 20-foot container, drums/IBCs securely palletized, labeled, ventilated, and braced for safe transport of Chromium Fog Inhibitor. |
| Shipping | Chromium Fog Inhibitor ships in sealed, corrosion-resistant containers to prevent leaks and contamination. Ground transport only, with proper hazard labeling and documentation. Store away from incompatible materials, and ensure secure upright positioning during transit. Direct exposure to moisture or extreme heat must be avoided to maintain product stability and safety. |
| Storage | Store Chromium Fog Inhibitor in a cool, dry, well-ventilated area away from direct sunlight, heat, and open flames. Keep the container tightly sealed to prevent moisture absorption and contamination. Avoid contact with strong oxidizers, acids, and bases. Ensure secondary containment and proper labeling to prevent accidental mixing and comply with safety regulations. |
| Shelf Life | Shelf life is typically 12 months when stored unopened in a cool, dry area away from moisture and direct sunlight. |
Exterior automotive trim lines that plate zinc die-cast door handles, steel grille frames and stainless beltline moldings deposit hexavalent decorative chromium over a semi-bright nickel and bright nickel couple. The chromium bath is operated at 150 g/L to 250 g/L CrO₃ with a chromic-acid-to-sulfate mass ratio of 150:1 to 250:1. Bath temperature is held at 35°C to 45°C, and cathode current density is 5 A/dm² to 15 A/dm² for 60 s to 180 s, producing a chromium deposit of 0.2 µm to 0.5 µm. Hydrogen and oxygen gas evolution at the part and anodes generates a chromic acid aerosol under these conditions. A chromium fog inhibitor is maintained at 0.5 mL/L to 2.0 mL/L; the resulting foam blanket height is controlled between 2 cm and 5 cm by surface-tension measurement. The air above the line is sampled according to NIOSH 7605 to verify that operator breathing-zone Cr(VI) remains below the OSHA 29 CFR 1910.1026 8-hour permissible exposure limit of 5 µg/m³ and action level of 2.5 µg/m³. Final parts are tested under ASTM B456 for decorative nickel-chromium coatings, including thickness, adhesion and neutral salt spray or CASS corrosion grade when specified by automaker material standards. Supplier technical bulletins for fluorosurfactant fog inhibitors specify dosing by bath volume after correcting for chromium trioxide and sulfate drag-out. The dosage is replenished per ampere-hour or per barrel of work processed; on hoist lines, additions are made at the beginning of the shift and after drag-out rinse samples show a drop in surface tension. If the foam blanket collapses below 1 cm at the tank edges, aerosol generation increases; if foam exceeds 5 cm, hydrogen gas can accumulate and create intermittent plating burns at higher current density. The process sequence for zinc die-castings includes alkaline cleaning, anodic electrocleaning, copper strike, semi-bright nickel, bright nickel and chromium. Baking of die-cast parts before nickel may be applied to prevent blistering. Terminal finished products are exterior door handles, grille rings, mirror covers and badge bezels. The chosen inhibitor must not introduce sulfuric acid imbalance; therefore the bath is titrated for sulfate after inhibitor additions and adjusted with sodium dichromate or sulfuric acid as required.
Hydraulic cylinder rods are processed in hard chromium baths containing 180 g/L to 300 g/L CrO₃ and sulfate maintained at a 100:1 chromic-acid-to-sulfate ratio. Operating temperature is 50°C to 60°C, cathode current density is 30 A/dm² to 60 A/dm², and plating time is set to deposit 20 µm to 100 µm of chromium per side before finish grinding. The substrate is typically SAE 1045 or 4140 steel bar stock, ground to size, degreased, masked in non-plate areas, reverse-etched in chromic acid, then plated with direct current or interrupted current waveforms. Fog inhibitor addition in these baths is constrained by foam persistence: a dosage of 0.5 mL/L to 1.0 mL/L is observed in plant practice, although high-temperature, high-current-density operation can collapse the foam blanket within 4 h if no replenishment is made. The foam blanket is held at 1 cm to 3 cm; excessive foam height traps hydrogen at the solution surface and can produce pitted deposits, while a collapsed blanket produces chromium mist at the tank rim. Bath maintenance includes daily sulfate titration, CrO₃ concentration correction, and air sampling by NIOSH 7605 at the loading station. Final rods are inspected for hardness in the range 800 HV to 1100 HV and for surface finish under ISO 6158 or ASTM B177. Terminal products are piston rods for construction machinery, mining roof supports, agricultural hydraulic cylinders and tailgate lifting cylinders. The finished rod is ground and polished to a surface roughness of 0.2 µm Ra or lower when specified. The limiting variable for fog inhibitor dosage is not chromium bath solubility but the gas evolution rate at high current density: above 60 A/dm², foam generation can become so rapid that even small concentrations of surfactant produce excessive foam height, while below 0.3 mL/L the bath no longer forms a complete surface cover at tank corners.
Typical operating windows across downstream chromium plating sectors are compared below. Values are ranges from publicly available plating tank operating records and supplier technical bulletins; published data for a specific fog inhibitor formulation is limited.
| Plating sector | Bath CrO₃ | CrO₃:SO₄ ratio | Temperature | Cathode current density | Fog inhibitor | Chromium thickness |
|---|---|---|---|---|---|---|
| Automotive metal decorative | 150 g/L–250 g/L | 150:1–250:1 | 35°C–45°C | 5 A/dm²–15 A/dm² | 0.5 mL/L–2.0 mL/L | 0.2 µm–0.5 µm |
| Hard chrome hydraulic rods | 180 g/L–300 g/L | 100:1 | 50°C–60°C | 30 A/dm²–60 A/dm² | 0.5 mL/L–1.0 mL/L | 20 µm–100 µm |
| Aerospace landing gear hard chrome | 200 g/L–280 g/L | 100:1 | 52°C–63°C | 31 A/dm²–62 A/dm² | 0.5 mL/L–1.5 mL/L | 50 µm–200 µm |
| Decorative plating on ABS/PC-ABS | 130 g/L–250 g/L | 150:1–220:1 | 32°C–40°C | 10 A/dm²–15 A/dm² | 0.5 mL/L–1.5 mL/L | 0.25 µm–0.5 µm |
| Roll/mold hard chrome reclamation | 180 g/L–260 g/L | 100:1 | 50°C–60°C | 30 A/dm²–50 A/dm² | 0.5 mL/L–1.0 mL/L | 25 µm–150 µm |
On high-strength steel landing gear components, hard chromium plating is performed to engineering requirements under SAE AMS 2460 and ASTM B177, with thickness typically specified at 50 µm to 200 µm on bearing journals, axle surfaces and cylinder bores. The bath contains 200 g/L to 280 g/L CrO₃ and sulfate at a 100:1 ratio, operated at 52°C to 63°C and 31 A/dm² to 62 A/dm². Chromium fog inhibitor is maintained at 0.5 mL/L to 1.5 mL/L so that a stable foam blanket of 1 cm to 2 cm covers the bath during tank idle and plating periods. Air monitoring at the tank ventilation slot uses NIOSH 7605, and the facility is required to comply with OSHA 29 CFR 1910.1026 8-hour PEL 5 µg/m³ and action level 2.5 µg/m³, as well as the EPA 40 CFR Part 63 Subpart N chromium electroplating NESHAP. Process sequence includes pre-plating magnetic particle inspection, alkaline cleaning, vapor degreasing, grit blasting or anodic corrosion removal, chromic acid reverse etch, hard chrome plating, and post-plate hydrogen embrittlement relief at 190°C to 210°C for 4 h when base metal tensile strength exceeds 1000 MPa. Final parts are ground to finished dimensions and checked for surface finish, adhesion, and non-destructive indication. Terminal products include main landing gear outer cylinders, nose gear axles, torque links and actuator piston rods. The fog inhibitor must not generate sulfur species that shift the sulfate ratio; bath sulfate is checked after each replenishment by centrifugal separation of lead sulfate and gravimetric or barium sulfate titration. Where EU REACH applies, chromium trioxide use requires authorisation, and the fog inhibitor formulation is selected to avoid restricted PFOS or PFOA substances under REACH Annex XVII.
Plating-on-plastics lines use an etching stage with chromic acid at 65°C to 70°C and 380 g/L to 420 g/L CrO₃ to produce micropores on ABS or PC/ABS, followed by a Pd/Sn activator, electroless nickel or copper, electrolytic copper, semi-bright nickel, bright nickel, and decorative hexavalent chromium. The final chromium bath is run colder than automotive metal trim: 32°C to 40°C, with 130 g/L to 250 g/L CrO₃, a sulfate ratio of 150:1 to 220:1, and cathode current density of 10 A/dm² to 15 A/dm² for 60 s to 180 s. Chromium thickness is 0.25 µm to 0.5 µm. Fog inhibitor is added at 0.5 mL/L to 1.5 mL/L; because the bath is sensitive to organic contamination from electroless nickel drag-in, the inhibitor must not destabilize the electroless nickel colloid or cause foam that entrains nickel sulfate into the chromium bath. Tank-side foam height is maintained at 1 cm to 3 cm. Compliance is verified by ASTM B604 for decorative electroplated coatings on plastics, including thermal-cycle adhesion, and by NIOSH 7605 for operator Cr(VI) exposure. Terminal parts are chrome-plated ABS radiator grilles, door mirror shells, automotive interior door pulls, faucet handles, and appliance control knobs. The fog inhibitor dosage may be raised after carbon treatment or air agitation because surface active agents can be stripped by the same treatment. Process control on these lines also includes surface-tension reading of the final chromium bath after activated carbon filtration, because carbon can remove surfactant and collapse the foam blanket within one to two shifts if not corrected.
Roll and mold reclamation shops operate hard chromium baths at 180 g/L to 260 g/L CrO₃ with a sulfate ratio of 100:1 and a temperature of 50°C to 60°C. Current density is generally 30 A/dm² to 50 A/dm², and deposit thickness after grinding is 25 µm to 150 µm depending on wear allowance. Chromium fog inhibitor is maintained at 0.5 mL/L to 1.0 mL/L; foam height is held below 2 cm because vertical roll tanks and conforming anodes create uneven gas release and entrapped foam can cause nodules at the upper end of the roll face. The process includes pre-machining, alkaline soak cleaning, electroclean, chromic acid reverse etch, chromium plating, and post-plate grinding to final surface finish. Compliance is assessed with ASTM B177 and ISO 6158, and air monitoring uses NIOSH 7605 at the tank rim. Terminal products are gravure printing cylinders, embossing rolls for nonwoven converting, extrusion die lips, and plastic injection mold cores and cavities. For mold surfaces, chromium improves release and wear resistance in glass-filled polymer injection; post-plate grinding removes grinding stock allowance from the as-plated surface to achieve flatness and dimensional restoration. The fog inhibitor concentration is adjusted after each tank decant or carbon treatment, and foam height is checked at the two tank ends because roll tanks with air agitation often show nonuniform foam distribution.
Mixed-part chromium plating lines that process fasteners, metal stampings, die castings, brass fittings and small machined components in the same hexavalent bath face variable drag-in of chloride, iron, copper and alkaline cleaner residue. The fog inhibitor concentration is not stable under these conditions; bromide and iron(III) carried into the bath can accelerate foam collapse, while excessive inhibitor addition produces dense foam that interferes with rack contact and causes solution entrapment in blind holes. Daily surface-tension measurement and foam height reading at a fixed tank position are used to maintain the fog inhibitor at 0.5 mL/L to 1.5 mL/L; additions are made in small increments after air agitation is stopped, and the bath is allowed to stand for 10 min before foam height is recorded. The bath is operated at 30°C to 55°C depending on part geometry, with current density from 5 A/dm² to 30 A/dm², so no single dosage applies across all rack loads. Occupational compliance requires Cr(VI) sampling by NIOSH 7605 in the loading and unloading zones, with results below the OSHA 29 CFR 1910.1026 8-hour PEL 5 µg/m³ and action level 2.5 µg/m³. Stack or tank exhaust emissions comply with EPA 40 CFR Part 63 Subpart N. Terminal products are general-purpose fasteners, brackets, hinges, plumbing fittings and hand tool parts. Published data for exact fog inhibitor dosages in mixed-part shops is limited; the effective range is established by air sampling and foam-height trials on each specific tank configuration. Feed rate is adjusted per rack surface area rather than per liter alone, because a full rack of cup-shaped parts produces a greater gas-shielding demand than flat stampings at the same bath volume.
Compliance and test references applicable to the above chromium plating sectors are summarized below.
| Standard or regulation | Application | Measured or required parameter |
|---|---|---|
| OSHA 29 CFR 1910.1026 | Worker exposure to Cr(VI) in all chromium plating sectors | 8-hour TWA PEL 5 µg/m³; action level 2.5 µg/m³ |
| EPA 40 CFR Part 63 Subpart N | Hard and decorative chromium electroplating NESHAP | Fume suppressant monitoring; emission limits vary by tank type |
| NIOSH 7605 | Air sampling at tank rim and breathing zone | Cr(VI) by ion chromatography |
| ASTM B456 | Decorative nickel-chromium coatings on metals | Thickness, adhesion, corrosion resistance |
| ASTM B604 | Decorative copper/nickel/chromium coatings on plastics | Thermal-cycle adhesion and thickness |
| ASTM B177 | Engineering hard chromium coatings | Adhesion and thickness requirements |
| ISO 6158 | Metallic coatings — electrodeposited coatings of chromium for engineering purposes | Hardness, thickness and surface finish |
| SAE AMS 2460 | Aerospace hard chromium plating | Process control and approval requirements |
| REACH Annex XVII | European restrictions on PFOS and PFOA in fog inhibitor formulations | Chemical restrictions for surface-active substances where applicable |
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Chromium Fog Inhibitor CFI-4300 is a low-foaming, non-PFOS anionic/nonionic liquid formulated for hexavalent hard chromium electroplating tanks. The supplied concentrate is a pale amber, water-miscible liquid with a density of 1.05 g/mL at 25 °C, a 1% solution pH of 7.3–8.1, and a dynamic viscosity of 18 mPa·s at 25 °C when measured with a Brookfield LVT viscometer at spindle 2 and 60 rpm. Its primary function is the reduction of chromic acid aerosol release driven by hydrogen evolution at the cathode surface. Bench-scale stalagmometer measurements in a 150 g/L CrO₃ / 1.5 g/L SO₄ bath show a surface tension plateau below 45 mN/m at dose rates from 0.3 mL/L to 0.6 mL/L according to ASTM D1331-14. This positions the product on the fume suppressant compliance pathway for hard chromium electroplating under 40 CFR Part 63 Subpart N. The difference from PFOS-based mist suppressants is the absence of perfluorooctane sulfonate and a lower persistent foam fraction under continuous air agitation, which reduces tank-top solids entrapment and drag-out.
The product is designed for hexavalent chromium baths containing 150–300 g/L CrO₃ and sulfate at a 100:1 to 75:1 chromic acid-to-sulfate mass ratio. The practical operating temperature window is 50–65 °C. Below 50 °C, surfactant diffusion to freshly generated gas–liquid interfaces declines, and static surface tension can remain below the limit while dynamic surface tension at the meniscus is insufficient. Above 65 °C, oxidative hydrolysis of the nonionic component accelerates, shortening effective bath life and increasing total organic carbon. At conventional hard chrome current densities of 30–75 A/dm², the dose range is 0.3–0.6 mL/L. The lower end is used for tanks operating at 30–45 A/dm² with mechanical agitation only; the upper end is reserved for racks running at 60–75 A/dm², high air agitation, or deposits above 100 µm where hydrogen bubble flux is higher.
Control is based on measured static surface tension, not solely on amp-hours. A surface tension value above 45 mN/m at 55 °C indicates insufficient surfactant activity. In production practice, the sample is collected from the tank weir after 15 min of air agitation, filtered through a 0.45 µm PTFE syringe filter, and measured by the Wilhelmy plate method or calibrated stalagmometer according to ASTM D1331-14. If the value exceeds 45 mN/m, an incremental addition of 0.05 mL/L is made and the bath is retested after 30 min.
| Property | Value / Method |
|---|---|
| Density at 25 °C | 1.05 g/mL, ASTM D4052-22 |
| Dynamic viscosity at 25 °C | 18 mPa·s, Brookfield LVT spindle 2, 60 rpm |
| Flash point, closed cup | >100 °C, ASTM D93-20 |
| Freezing point | -4 °C |
| Water solubility | Complete at 20 °C |
| Surface tension at 0.5 mL/L in deionized water | 28 mN/m, ASTM D1331-14 |
| Regulatory pathway | 40 CFR Part 63 Subpart N surface tension limit for hard chromium |
On a 5,000 L hard chromium line with a 15,000 A rectifier and continuous exhaust, the inhibitor is pre-diluted at 1:10 with deionized water and metered into the filter return line at a rate not exceeding 0.1 mL/L per hour. Direct slug addition near lead anodes has produced localized organic oxidation foam and a temporary rise in bath carbonaceous loading. The product is not introduced through the anode compartment, and addition during zero-current standby is preferred. In continuous operation at 55 °C and 60 A/dm², the steady-state consumption observed on production rack lines is typically 0.04–0.07 mL/L per 8 h for a 150 g/L CrO₃ bath. Consumption rises nonlinearly when iron contamination exceeds 5 g/L or when drag-out losses exceed 2 L/h from a 5,000 L bath.
Because mist suppression demand varies with workload and bath age, a fixed timer-controlled bleed is not adequate. The surface tension target must be verified at shift change and after any addition of chromic acid or sulfate. A surface tension value above 45 mN/m should not persist for more than 2 h during active plating.
At 75 A/dm², the Faradaic hydrogen evolution rate is approximately 0.57 L/min per dm² at standard temperature and pressure, based on 7.6 mL/A·min per ampere for the two-electron reduction of water. This gas flux is sufficient to mechanically rupture foam lamellae and transport aerosol droplets into the exhaust stream if the dynamic surface tension at the cathode interface does not remain below the 45 mN/m static limit. A product dose that produces a static surface tension of 42 mN/m may still fail in a high-speed rack line because the surfactant adsorption rate cannot keep pace with the freshly generated gas–liquid interface. Production-scale observations on a 3,000 L rotary hard chrome line showed visible droplet accumulation at extraction duct corners when the static surface tension remained between 43 mN/m and 48 mN/m for more than 4 h. Mist carryover was reduced only after the dose was raised to 0.6 mL/L and the surface tension fell below 38 mN/m.
The maximum bubble pressure method at 20 Hz is a better predictor of mist suppression in this regime. Published data for this specific configuration is limited, but production experience indicates that the static Wilhelmy value should be maintained at least 4–6 mN/m below the regulatory ceiling to account for dynamic surface tension lag. At current densities below 40 A/dm², the lower end of the dose range is adequate because the hydrogen bubble generation rate is lower and surface foam drainage is less chaotic.
The following bench data were generated in a 150 g/L CrO₃ / 1.5 g/L SO₄ bath at 55 °C using 0.5 mL/L active product. Foam height was measured by the Ross-Miles pour method at 25 °C; surface tension was measured after 30 min equilibration according to ASTM D1331-14.
| Parameter | CFI-4300 | PFOS-based suppressant | Nonionic alcohol ethoxylate |
|---|---|---|---|
| Static surface tension at 0.5 mL/L | 32 mN/m | 21 mN/m | 38 mN/m |
| Ross-Miles initial foam height | 12 mm | 85 mm | 95 mm |
| Foam persistence after 5 min | 2 mm | 60 mm | 75 mm |
| Maximum stable current density in 150 g/L CrO₃ at 55 °C | 80 A/dm² | 70 A/dm² | 45 A/dm² |
| Regulatory profile | No PFOS/PFOA; 40 CFR Part 63 Subpart N surface tension pathway | PFOS-restricted under EU 2019/1021 | No PFOS; higher carbon loading in bath |
CFI-4300 differs from PFOS-based suppressants in that it cannot achieve surface tension below 25 mN/m, but it provides sufficient wetting for hard chrome at the compliance target. The product also avoids the persistent foam layer associated with conventional perfluorinated surfactants, reducing the need for mechanical foam-breaking and lowering the amount of organic material carried into the exhaust stack. Relative to nonionic alcohol ethoxylates, CFI-4300 maintains a lower persistent foam height and does not require supplementary defoamer additions during high-air-agitation rack cycles.
CFI-4300 is not recommended for trivalent chromium sulfate electrolytes because the functional group hydrolyzes at pH below 2.5. The product is incompatible with strong cationic polyelectrolyte flocculants; exposure at ambient temperature produces a stringy precipitate that deposits on heat exchangers and filter housing walls. Free chloride contamination above 50 mg/L from precleaner drag-in should be avoided because chloride ion catalyzes decomposition of the nonionic component and raises bath total organic carbon. At the recommended dose, the product has no measurable effect on microcrack density of deposits above 25 µm; excessive dosing above 1.0 mL/L can produce organic inclusion at the deposit surface and reduce Vickers hardness by approximately 5%.
