Nano-Scale Coating

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  • NANO-SCALE Cr(III)/Ce(III) COATING

    Cutting-edge nanotechnology for long-lasting heat exchanger protection

    Microchannel heat exchanger

NANO-SCALE Cr(III)/Ce(III) COATING FOR MICROCHANNEL HEAT EXCHANGERS

Developed by Kaltra in collaboration with leading experts in modern chemistry, the Nano-scale Cr(III)/Ce(III) Coating is an advanced protective solution tailored for aluminum heat exchangers. After five years of focused research and innovation, this next-generation coating delivers outstanding corrosion resistance while preserving 100% of the coil’s thermal performance.

This ultra-thin, uniform nano-level film can be applied to both internal and external surfaces of the coil, providing comprehensive protection. It features hydrophobic properties, extended chemical compatibility—including a broad pH range for heat transfer fluids—and a smooth surface finish with a roughness of just 0.1 µm. In addition to superior functional performance, the coating offers a clean, refined appearance.

6000+ SWAAT HOURS

WITH 3F05 BASE ALLOY

5.0 - 8.5 PH RANGE

ADVANCED PROTECTION

5µm THICKNESS

INNER AND OUTER SURFACES

5+ YEARS WARRANTY

FOR C5 & CX ENVIRONMENTS

BeforeAfter

NANO-SCALE COATING: CORE BENEFITS

  • Outstanding corrosion resistance on both internal and external surfaces, even in C5 and CX environments (ISO 12944:2018)
  • Extended service life—4 to 8 times longer than uncoated heat exchangers
  • Broad pH compatibility for use with water and glycol-based fluids
  • Maintains 100% of the coil’s thermal performance
  • Hydrophobic surface enhances efficiency under wet conditions
  • Long-term reliability with warranty coverage of 5 years or more
  • Ultra-smooth, clean, and visually refined finish

COATING APPLICATION PROCESS

Kaltra’s nano-scale Cr(III)/Ce(III) coating process involves a sequence of precisely controlled steps to ensure maximum corrosion protection and product integrity.

Each coil is first inspected for physical damage or contaminants, then undergoes thorough cleaning and rinsing. A specially formulated, low-viscosity coating—rich in trivalent chromium, cerium, and rare earth elements—is applied via immersion and flooding to achieve complete internal and external surface coverage. Post-rinsing ensures purity before the final helium leak test verifies the structural integrity of the coil.

INCOMING CONTROL

Each coil undergoes a detailed inspection to detect any physical defects or surface contaminants that could compromise coating adhesion.

CLEANING & RINSING

To prepare the surface for nano-coating, coils are cleaned with an alkaline solution to remove oils, dirt, and other residues. A multistage rinsing process follows this to ensure a clean, residue-free surface ready for coating.

COATING STAGE

The coating solution is a low-viscosity aqueous formulation composed of trivalent chromium, trivalent cerium, selected rare earth elements, corrosion inhibitors, and bonding agents—including a silane coupling agent. Free of solids larger than 1 µm, it allows for precise, uniform application through two methods: immersion for external surfaces and flooding for internal surfaces of heat exchangers. The application process, lasting 3 to 6 minutes, ensures smooth nanoparticle deposition and complete surface coverage. After application, the solution is thoroughly drained.

POST-RINSE

The coils are thoroughly rinsed with deionized water to eliminate any impurities.

HELIUM LEAK TEST

After the coating process is complete, each coil undergoes a helium leak test to verify its integrity and ensure that no damage occurred during processing.

COATING PERFORMANCE MATRIX

BARE

E-COATING

TCP-COATING

NANO-SCALE Cr(III)/Ce(III) COATING

Surface

–

OUTER

OUTER

OUTER/INNER

SWAAT hours
(Alloy 3F03)

2500

4000+

3000

4750

SWAAT hours
(Alloy 3F05)

3000

6000+

4000+

6000+

Film thickness [µm]

–

12.5–50.0

≤3.0

≤5.0

Base material

–

EPOXY RESIN

Cr³+

Cr³+/Ce³+

Surface roughness [µm]

0.5

0.8

0.6

0.1

pH range

4.0–8.5

6.5–8.5

6.5–7.5

5.0–8.5

Surface wettability

HYDROPHILIC

HYDROPHOBIC

HYDROPHILIC

HYDROPHOBIC

COATING SELECTION

ISO 12944:2018
Corrosivity Category

Corrosivity

BARE COIL
(ALLOY 3F03)

BARE COIL
(ALLOY 3F05)

TCP-COATING
(ALLOY 3F03)

TCP-COATING
(ALLOY 3F05)

E-COATING
(ALLOY 3F03)

E-COATING
(ALLOY 3F05)

NANO-SCALE Cr(III)/Ce(III) COATING
(ALLOY 3F03)

NANO-SCALE Cr(III)/Ce(III) COATING
(ALLOY 3F03)

C1

VERY LOW

✓

✓

✓

✓

✓

✓

✓

✓

C2

LOW

✓

✓

✓

✓

✓

✓

✓

✓

C3

MEDIUM

✓

✓

✓

✓

✓

✓

✓

C4

HIGH

✓

✓

✓

✓

✓

✓

C5

VERY HIGH

✓

✓

✓

✓

✓

CX

EXTREME

✓

✓

✓

✓

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