Polylloy Coating Grades by Temperature and Gas Chemistry: 7 Options

Polylloy Coating Grades: Key Points

• Polylloy Coatings publishes bulletins for seven grades rated from 160 °C (320 °F) to 625 °C (1,157 °F); pick the grade whose continuous and spike limits cover the duty.
• Temperature sets the shortlist; gas chemistry, abrasion and immersion decide it.
• CorrosionGard®-160S cures at ambient temperature; the other six grades are heat-cured, with final heat cured activation completed during start-up using process heat.
• Immersion is rated for FlueGard®-225SQC and CorrosionGard-160S only; FlueGard-425S, StackGard®-255SQW, KilnGard®-600SCW and WearGard®-625S are gas-phase grades.
• Taber abrasion ranges from 20 mg (FlueGard-455CHT) to below 150 mg (FlueGard-425S), so dusty, high-velocity zones narrow the choice.
• Every grade needs a Society for Protective Coatings (SSPC) SP10 near-white blast with a profile above 3 mils (75 µm); a site that cannot meet the preparation or cure route is not a fit.

Choose among Polylloy coating grades by matching your continuous temperature and excursions to a published service limit, then filter by gas chemistry. CorrosionGard-160S covers 160 °C, FlueGard-225SQC 225 °C, StackGard-255SQW 255 °C, FlueGard-425S 425 °C, FlueGard-455CHT 455 °C (850 °F), KilnGard-600SCW 600 °C and WearGard-625S 625 °C. Abrasion, immersion and cure route decide between neighbors.

Polylloy Coating Grades and the Polymer-Alloy-Ceramic Chemistry Behind Them

Polylloy coating grades are the seven bulletin-backed protective coatings in the FlueGard, StackGard, KilnGard, CorrosionGard and WearGard families, each defined by a published service temperature, chemistry and cure route.

What a Polymer-Alloy-Ceramic Coating Is

Polymer-alloy-ceramic is Polylloy Coatings' name for its hybrid coating systems, engineered for chemical resistance, thermal stability and abrasion protection. Chemistries differ by grade: FlueGard-225SQC is a polymeric alloy, FlueGard-425S an inorganic polymeric coating, FlueGard-455CHT a ceramic coating, and KilnGard-600SCW and WearGard-625S nano-ceramic composites. Polymer-alloy-ceramic coatings are set against conventional linings in novolac, vinyl ester and hybrid coatings compared.

Who Formulates and Who Applies

Polylloy Coatings formulates, supplies, specifies, trains and supervises. Certified partners in its global network apply the coatings.

Selection Criteria for Matching a Polylloy Grade to Temperature and Gas Chemistry

Matching a Polylloy grade to a duty uses six criteria, applied in this order:

• Continuous service temperature and excursion (spike) temperature against the bulletin limit.
• Gas and condensate chemistry: sulfur trioxide (SO3), sulfur dioxide (SO2), hydrogen chloride (HCl), hydrogen fluoride (HF), nitrogen oxides (NOx) and alkaline condensate.
• Abrasion from dust, read as Taber mass loss.
• Immersion or splash contact versus gas-phase exposure.
• Cure route versus the outage and start-up plan.
• Surface preparation the site can achieve.

Temperature has two sides. Acid dew point is typically 120 to 160 °C depending on SO3 and moisture, so the coldest metal temperature matters as much as the gas temperature.

Polylloy Coating Grades at a Glance

The table lists the seven Polylloy grades in service-limit order. Spike and immersion values come from the June 2026 brochure snapshot, the rest from each bulletin; Taber uses a CS-17 wheel, 1 kg load and 1,000 cycles. ESP means electrostatic precipitator.

Neighboring grades overlap on temperature, so chemistry, dust and immersion decide.

CorrosionGard-160S for Ambient-Cure Protection to 160 °C

CorrosionGard-160S is the Polylloy grade for ambient and moderate-temperature chemical service where no start-up heat is available.

Suited To

CorrosionGard-160S suits steel structures, storage tanks and pressure vessels handling corrosive gases and chemicals, and internal or external steel in smelters, cement plants and incinerators.

What It Is

CorrosionGard-160S is a two-component coating that cures at room temperature, applied as a single layer at 20 to 30 mils, with zero volatile organic compounds (VOC) as supplied. Its service limit is 160 °C (320 °F), with a brochure spike rating of 180 °C.

Key Features

• One-week immersion weight gain below 0.5% in 10% HCl, 54% phosphoric acid (H3PO4), 10% sulfuric acid (H2SO4) and water (ASTM International D471).
• Adhesion above 2,000 psi and Taber below 100 mg; tolerates airborne contamination during surface preparation.

Cost Factors

CorrosionGard-160S cost depends on area, access, SSPC-SP10 blasting and single-coat thickness; no heat-cure planning is needed.

Pros and Cons

Pros

• The ambient-cure grade, so it suits equipment that never sees process heat.
• Rated for immersion service.

Cons

• The lowest service limit of the seven; a hot gas path above 160 °C needs a higher grade.
• Media outside the tested list still need evaluation.

FlueGard-225SQC for Baghouses, ESPs and Acid Gas to 225 °C

FlueGard-225SQC addresses acid dew point corrosion in dust collection and flue gas equipment within 225 °C.

Suited To

FlueGard-225SQC suits baghouses, electrostatic precipitators and ducts in cement plants and waste incinerators; flue gas desulfurization (FGD) scrubbers, ducts and chimneys in power plants and refineries; and smelter and battery-recycling ducts, filters and stacks. The wider set of baghouse corrosion protection options is compared separately.

What It Is

FlueGard-225SQC is a two-component polymeric alloy, 100% solids, mixed 4:1 and sprayable (Sprayable Quick Cure). Its service limit is 225 °C (437 °F), with a brochure spike rating of 270 °C. It belongs to the FlueGard coating range with two hotter grades.

Key Features

• Bulletin resistance list: SO3, SO2, HCl, carbon dioxide (CO2), HF and NOx; one-week immersion below 1.0% in 37% HCl and 3% HF, and below 0.5% in 36% H2SO4.
• Adhesion above 3,000 psi (ASTM D4541); Taber below 30 mg; immersion-rated.
• Polylloy's own six-month sulfuric acid immersion test in 56% H2SO4 at 60 °C showed no observed deterioration.

Cost Factors

FlueGard-225SQC cost depends on area, casing access, blast and profile, freight and start-up planning.

Pros and Cons

Pros

• HF is on its resistance list.
• FlueGard coatings on three coal mill baghouses at cement plants in Mexico were inspected after about 20, 15 and 16 years; the 16-year unit is specifically FlueGard-225SQC.

Cons

• 225 °C ceiling.
• Heat-cured: final heat cured activation is completed during start-up using process heat, so the start-up must deliver it.
• SSPC-SP10 preparation is mandatory.

StackGard-255SQW for Steel Stacks, Ducts and Fans to 255 °C

StackGard-255SQW serves steel chimneys and fans running slightly hotter than baghouse service.

Suited To

StackGard-255SQW suits inside surfaces of steel chimneys connected to baghouses, ESPs and ducts; gas scrubbers, ducts and fans in power plants and refineries; and smelter ducts, filters and scrubbers. Other approaches to steel stack corrosion protection are covered on a dedicated page.

What It Is

StackGard-255SQW is a two-component, 4:1 Sprayable Quick Cure Wide temperature range coating. Its service limit is 255 °C (491 °F), with a brochure spike rating of 270 °C.

Key Features

• Resistant to SO3, SO2, HCl and NOx plus dust abrasion; one-week immersion below 1.5% in 37% HCl and below 0.5% in 10% H2SO4.
• Taber below 70 mg; adhesion above 1,000 psi; maximum dry film thickness (DFT) 35 mils.

Cost Factors

StackGard-255SQW cost depends on stack height and access (in place, on the ground or before assembly), area and start-up heat.

Pros and Cons

Pros

• A service limit 30 °C above FlueGard-225SQC, aimed at stacks and fans.

Cons

• Not immersion-rated; heat-cured.
• HF is not on its resistance list, so HF-bearing gas points back to FlueGard-225SQC within its limit.

FlueGard-425S for Corrosive Flue Gas to 425 °C with Peaks to 500 °C

FlueGard-425S covers hot, corrosive gas paths beyond the polymeric grades with moderate dust. Non-Polylloy options for high temperature coatings above 400 °C are compared separately.

Suited To

FlueGard-425S suits baghouses, ESPs and ducts in metal smelters and waste incinerators; gas scrubbers, ducts and chimneys in power plants and refineries; and conditioning towers and stacks in cement and lime plants.

What It Is

FlueGard-425S is a single-component inorganic polymeric material with a high load of reactive fillers, applied by air spray, roll or brush at 20 to 25 mils per coat. Its service limit is 425 °C (797 °F), with peaks to 500 °C.

Key Features

• Resistant to SO3, SO2, HCl, CO2 and NOx plus dust abrasion.
• Taber below 150 mg; adhesion above 700 psi; Shore D above 80.

Cost Factors

FlueGard-425S cost depends on area, access, blasting, solvent handling during application and start-up heat.

Pros and Cons

Pros

• Covers hot ducts and towers with excursions to 500 °C.

Cons

• Not immersion-rated; contains solvent.
• The highest Taber value of the seven, so heavy dust favours FlueGard-455CHT or WearGard-625S.

FlueGard-455CHT for Hot Ducts with Condensate and Abrasion to 455 °C

FlueGard-455CHT targets hot, dusty ducts that cycle through the dew point.

Suited To

FlueGard-455CHT suits hot ducts where acidic or alkaline condensate and dust abrasion act together, including cement-plant ductwork with frequent shutdowns.

What It Is

FlueGard-455CHT is a two-component, water-based ceramic corrosion and abrasion coating, applied in two coats to 16 to 20 mils total. Its service limit is 455 °C (850 °F).

Key Features

• Good resistance to acidic and alkaline condensates; Taber 20 mg, the lowest of the seven; Shore D above 80; Elcometer adhesion above 1,000 psi (7 MPa) on sandblasted carbon steel.
• Swiss cement plant duct (October 2024, about 75 m², 220 to 240 °C continuous, about 50 shutdowns a year): no visible widespread delamination in inspected areas at about 17 months; heavy dust prevented full inspection.

Cost Factors

FlueGard-455CHT cost depends on two-coat application time, area, blasting, shelf-life planning (6 months) and start-up heat.

Pros and Cons

Pros

• Pairs condensate resistance with the lowest Taber value of the seven.

Cons

• Two coats rather than one; shorter shelf life to plan around.
• Immersion and spike ratings are not stated in its data sheet; heat-cured.

KilnGard-600SCW for Kiln Shells Beneath Refractory to 600 °C

KilnGard-600SCW protects steel against under-refractory corrosion where alternative fuels raise chloride and sulfur load.

Suited To

KilnGard-600SCW suits cement and lime kiln shells beneath refractory, industrial furnaces in waste incineration plants, and ducts, filters and stacks in copper, zinc or lead smelters beneath refractory.

What It Is

KilnGard-600SCW is a two-component, water-based nano-ceramic composite applied to the steel before the refractory goes in. Its service limit is 600 °C (1,112 °F), with a brochure spike rating of 625 °C.

Key Features

• Resistant to hot corrosive gases and severe abrasion; one-week immersion below 1.0% in 50% sodium hydroxide (NaOH) and below 0.5% in 36% H2SO4.
• Mexico kiln: more than 1.3 mm shell loss in 11 months uncoated, and no measurable loss over a further 12 months on the same section with KilnGard-600SCW.

Cost Factors

KilnGard-600SCW cost depends on the reline schedule, shell area and condition, blasting inside the kiln and refractory coordination.

Pros and Cons

Pros

• Protects the shell where condensate forms behind the lining.

Cons

• Only applicable when the refractory is out; does not replace refractory.
• Not immersion-rated; final heat cured activation is completed during kiln start-up using process heat.

WearGard-625S for Hot, Abrasive Gas Streams to 625 °C

WearGard-625S is the Polylloy grade for hot gas streams carrying abrasive dust.

Suited To

WearGard-625S bulletin applications are high-temperature ducts in cement and lime, industrial fans and ducts in coal power and waste incineration, and smelter ducts, filters and stacks. Beyond the bulletin list, Polylloy names cyclones, chutes, hoppers, transfer points, separators and particulate impingement zones as wear zones at portfolio level.

What It Is

WearGard-625S is a two-component nano-ceramic abrasion-resistant material. Its service limit is 625 °C (1,157 °F).

Key Features

• Taber below 30 mg; Shore D above 95; adhesion above 1,000 psi (ASTM D4541).
• One-week immersion below 1.0% in 50% NaOH and below 0.5% in 36% H2SO4.

Cost Factors

WearGard-625S cost depends on wear-zone mapping, area, blasting, shelf-life planning (3 to 6 months) and start-up heat.

Pros and Cons

Pros

• The highest service limit of the seven, built for hot abrasion.

Cons

• Not immersion-rated; no completed WearGard-625S case study is published yet, so proof is bulletin data.
• Heavy lump impact still calls for liners.

How the Seven Polylloy Grades Were Selected and Ordered

Seven Polylloy grades are listed because seven have published bulletins with service limit, chemistry, cure route, Taber and application data. The June 2026 brochure also names CorrosionGard-160SH2, CorrosionGard-50SM and WearGard-225SG, which are also available but fall outside this comparison.

The grades are ordered by service limit, 160 °C to 625 °C, not by preference; values are typical bulletin values. Each was read against the six criteria: temperature, chemistry, abrasion, immersion, cure route and preparation.

How to Choose a Polylloy Grade for Your Operating Temperature and Gas Chemistry

Choosing a Polylloy grade follows six steps:

1. Record continuous, minimum metal and excursion temperatures.
2. Shortlist grades whose continuous and spike limits cover them.
3. Filter by chemistry: HF points to FlueGard-225SQC, alkaline plus acidic condensate to FlueGard-455CHT, and liquid contact to FlueGard-225SQC or CorrosionGard-160S.
4. Filter by dust: Taber values separate neighboring grades.
5. Confirm the cure route fits the outage: ambient for CorrosionGard-160S, start-up process heat for the rest.
6. Confirm SSPC-SP10 with a profile above 3 mils is achievable.

Some duties fall outside every grade: metal above 625 °C, a refractory failure, or wet immersion in a gas-phase grade's zone needs a different solution, sometimes 316 stainless steel or a higher alloy.

Pricing for any Polylloy grade is project-specific, depending on operating environment, coating system, equipment condition, project size and application requirements. To match a grade to your duty, request a coating evaluation with equipment type, coated area, operating temperatures, gas chemistry, abrasion, location and outage timing.

FAQs

Which Polylloy Coating Suits My Operating Temperature?

Match your continuous temperature and excursions to a published limit. CorrosionGard-160S runs to 160 °C, FlueGard-225SQC to 225 °C, StackGard-255SQW to 255 °C, FlueGard-425S to 425 °C with peaks to 500 °C, FlueGard-455CHT to 455 °C (850 °F), KilnGard-600SCW to 600 °C and WearGard-625S to 625 °C. Chemistry, abrasion and immersion then decide.

What is a Polymer Alloy Ceramic Coating?

Polymer-alloy-ceramic is Polylloy Coatings' name for its hybrid coating systems, engineered for chemical resistance, thermal stability and abrasion protection on steel. Grade chemistries differ: FlueGard-225SQC is a polymeric alloy, FlueGard-425S an inorganic polymeric coating, and FlueGard-455CHT, KilnGard-600SCW and WearGard-625S ceramic or nano-ceramic.

How Do I Choose a Coating by Gas Chemistry as Well as Temperature?

Start with temperature, then read each bulletin's resistance list against your gas. FlueGard-225SQC lists HF alongside SO3, SO2, HCl and NOx; FlueGard-455CHT lists acidic and alkaline condensates; CorrosionGard-160S and FlueGard-225SQC are rated for immersion. Dust load narrows the choice further, because Taber values range from 20 mg to below 150 mg.

Which Polylloy Coatings Can Be Used in Immersion Service?

FlueGard-225SQC and CorrosionGard-160S are rated for immersion in Polylloy's June 2026 brochure. FlueGard-425S, StackGard-255SQW, KilnGard-600SCW and WearGard-625S are gas-phase grades and are not rated for immersion. The FlueGard-455CHT data sheet does not state an immersion rating, so confirm any liquid contact with Polylloy's technical team before specifying.

Do All Polylloy Coatings Need Heat to Cure?

No: CorrosionGard-160S cures at ambient temperature, so it suits equipment that never sees process heat. The other six grades are heat-cured: final heat cured activation is completed during start-up using process heat. Every Polylloy project review therefore plans the start-up that brings the coated steel into service.

Which Polylloy Grade Handles the Most Abrasion?

On bulletin Taber data, FlueGard-455CHT lists 20 mg, and WearGard-625S and FlueGard-225SQC list below 30 mg, measured with a CS-17 wheel, 1 kg load and 1,000 cycles. FlueGard-425S lists below 150 mg. For hot, dusty gas streams to 625 °C, WearGard-625S is the abrasion grade; heavy lump impact still calls for liners.

What Surface Preparation Do Polylloy Grades Require?

Every Polylloy bulletin calls for SSPC-SP10 / NACE No. 2 near-white blast cleaning with an angular profile above 3 mils (75 µm). Certified partners blast and apply under Polylloy supervision. A site that cannot meet this standard or the cure route is not a fit, whatever the corrosion problem.