Four complementary Lubrizol technologies help formulators select and validate the right protection for each process, fluid and exposure condition.
Rust is the oxidation of iron and steel, while corrosion is the broader degradation of metals. For formulators, the practical challenge is selecting protection that matches each stage of the ferrous-metal lifecycle: machining in water- or oil-based fluids, storage and transportation, and long-term outdoor exposure. That can require water-soluble or oil-soluble corrosion inhibitors, thin-film rust preventives or heavy-duty protective films.
Why Rust Protection Is a Formulation Decision, Not an Afterthought
Corrosion begins when unprotected metal encounters humidity, salt or process fluids—from steel leaving the mill to components in transit or idle equipment. NACE International, now AMPP, estimated its global annual cost at US$2.5 trillion. For formulators of rust preventives, metalworking fluids and industrial lubricants, selecting the right corrosion inhibitor is therefore a core formulation decision.
Selection starts with the duration and severity of exposure. Corrosion inhibitors provide in-process protection in oil-, solvent- or water-based fluids, including metal processing fluids, hydraulic fluids, gear oils and greases. Thin-film rust preventives protect surfaces during machining, shipment and storage, while heavy-duty products address long-term or outdoor exposure. The chemistry should therefore be validated for the intended protection scenario.
The Challenge Changes With the Application
The required protection changes substantially across processing, transit, in-service use and outdoor exposure.
- Steel and metal processing. Coils, sheets and machined parts need thin interim films that resist humidity and staining through processing and storage, then remove easily before the next step.
- Automotive and component manufacturing. Engine, driveline and chassis parts must remain corrosion-free through extended transit across climate zones. Salt-spray and humidity resistance at a practical film weight are critical.
- Industrial lubricants and fluids. In hydraulic fluids, gear oils, greases and metalworking fluids, rust inhibition must perform in service and in the presence of water without compromising water separation or base-oil solubility.
- Equipment, infrastructure and marine exposure. Machinery, structures, pipelines and marine equipment may remain outdoors for months, requiring long-duration, UV-stable protection that still allows inspection beneath the film.
Across these applications, formulators also face tighter VOC and labelling requirements, petroleum-wax supply concerns and more demanding solubility in Group II and higher base oils.
What a Fit-for-Purpose Rust Preventive Additive Must Deliver
Candidate chemistry should be tested against the conditions the finished product will face:
- Corrosion performance in relevant standard tests: ASTM B117 salt spray, ASTM D1748 humidity, ASTM D1014 outdoor exposure and, for in-service fluids, ASTM D665 rust prevention.
- The right film: thin and removable for interim protection; robust, clear and UV-stable for outdoor weathering or visual inspection.
- Compatibility with existing base oils, solvents and co-additives, including lower-VOC diluents.
- Water separation, so in-service fluids shed rather than retain contaminating water.
- Practical melting, pumping and blending behaviour for existing plant equipment.
- A suitable regulatory profile: labelling at the intended treat rate, heavy-metal content and target-market registration.
How Water-Based Metalworking Fluids Protect Ferrous Metals
Water-based metalworking fluids cool and lubricate effectively, but dissolved oxygen, chloride and sulphur species can attack freshly machined ferrous surfaces. Protection may weaken as coolant ages, reserve alkalinity falls, hard-water contamination rises or microbial growth alters the fluid. The inhibitor must therefore protect during processing and short-term storage without unacceptable foam, residue or stability issues.
For water-based systems, a neutralised organic polycarboxylic acid can form a highly effective water-soluble inhibitor that protects ferrous surfaces without leaving sticky residues after the water phase evaporates. The chemistry must also support low foaming and hard-water stability. Performance should be verified at the intended neutralisation, treat rate, dilution and water hardness using appropriate corrosion and stability testing.
Four Lubrizol Technologies Across the Protection Lifecycle
Lubrizol, supplied through IMCD, offers four complementary technologies for distinct stages of ferrous-metal protection: LUBRIZOL® MT2285 for water-based fluids, LUBRIZOL® IC9RTD2 for oil-based fluids, ALOX® MT1000 for thin-film protection during indoor storage and transit, and ALOX® MT9335 for demanding outdoor exposure.
LUBRIZOL® MT2285: water-soluble corrosion control.
LUBRIZOL® MT2285 is an 85%-active solid organic polycarboxylic acid that is neutralised, commonly with an amine, to form a water-soluble corrosion inhibitor and is positioned as an evolution of BECROSAN™ 2131. In Lubrizol tests, triethanolamine-neutralised material achieved a 2.0% corrosion breakpoint in the ISP-287 cast-iron chip test, nine days in ASTM D1748 humidity testing at 5%, and clear, deposit-free hard-water stability after 24 hours at 200 and 1,000 ppm at 5%. It combines ferrous-metal protection with low foam, no sticky residue after evaporation, hard-water stability, easy handling and low odour.
LUBRIZOL® IC9RTD2: oil-soluble corrosion inhibition.
LUBRIZOL® IC9RTD2 is a liquid corrosion inhibitor based on a proprietary sulfonate carboxylate complex for oil-based industrial lubricants. Its ferrous-corrosion performance and solubility across a wide range of base oils support use in rust preventive fluids, hydraulic fluids, gear oils and greases. Lubrizol data show a pass in ASTM D665B synthetic-seawater testing at 415 ppm in ISO 46 hydraulic oil, more than 60 days in ASTM D1748 humidity testing at a 5% treat rate in oil and D60 solvent, and increasing ASTM B117 salt-spray protection with treat rate in naphthenic oil and D60 solvent. At 13% or less, finished products may not require skin-sensitiser labelling, although classification depends on the complete formulation and applicable local regulations and remains the formulator’s responsibility.
ALOX® MT1000: petroleum-wax-free thin-film rust prevention.
ALOX® MT1000 is a petroleum-wax-free thin-film rust preventive additive based on engineered synthetic wax. The current Lubrizol Product Data Sheet describes a barium-free and heavy-metal-free composition, a lower melting temperature for easier manufacture, global registration status and solubility in a range of diluents. Its synthetic-wax content provides a reliably sourced alternative to petroleum-wax technology. Lubrizol performance data should be evaluated in the complete formulation and under the intended test conditions.
ALOX® MT9335: clear, UV-stable heavy-duty protection.
ALOX® MT9335 is a heavy-duty rust preventive additive based on hybrid polymer technology. It forms a clear, flexible, dry-to-touch, self-healing waxy film that permits visual inspection. In Lubrizol testing on 1008 steel Q panels, coatings applied at a wet-film thickness of 203.2 µm and diluted to 67.5 wt% in mineral spirits averaged 3,309 hours to failure in ASTM B117 salt spray, compared with 1,932 hours for the industry-standard chemistry. At 45 and 67.5 wt%, ALOX® MT9335 averaged approximately 213 and 627 days respectively in ASTM D1014 outdoor exposure, and films showed minimal rust or discolouration after 500 hours of ASTM G154 Cycle 1 UV exposure. It also provides cold-temperature flexibility and drip-sag resistance and can be formulated with calcium sulfonates, petroleum and micronised waxes, and polyisobutylene thickeners.
Selecting among these technologies requires matching the fluid system and substrate with the required protection duration, application method and operating environment, then validating performance in the complete formulation.
How IMCD Supports Metal Protection Formulators
IMCD’s technical teams help formulators move from application requirements to a validated formulation by supporting chemistry selection, performance testing, compatibility assessment and regulatory documentation.
- Select the right chemistry: water- or oil-soluble corrosion inhibitors, or thin-film and heavy-duty rust preventives.
- Validate performance: evaluate formulations against cast-iron corrosion, salt spray, humidity and outdoor-exposure benchmarks.
- Navigate requirements: support compatibility decisions and the regulatory documentation expected for finished products.
Connect with an IMCD technical expert to discuss the Lubrizol technology that best fits your formulation.