NdFeB Magnet Coating Performance Overview
This table compares common coatings applied to NdFeB magnets to prevent corrosion and meet application needs. It evaluates key parameters such as thickness, appearance, and resistance performance in tests like Salt Spray, PCT, and Damp-heat. A star rating system indicates relative performance levels for quick assessment. This overview assists in selecting the most suitable coating based on environmental exposure and functional requirements.
| Coating Type | Thickness | Appearance | PCT Resistance | Salt Spray Resistance | Damp-heat Resistance | Acid & Alkali Resistance | Oil Resistance |
| Zn (White Zn) | 5-12 µm | Silver-white/Bluish-white | ⭐ | ⭐⭐ | ⭐⭐⭐ | ⭐ | ⭐ |
| Zn (Color Zn) | 5-15 µm | Iridescent/Yellowish | ⭐ | ⭐⭐⭐ | ⭐⭐⭐ | ⭐ | ⭐ |
| Ni+Cu+Ni | 10-25 µm | Bright Silver | ⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐ |
| Ni+Cu+Ni+Sn | 12-30 µm | Tin-white/Matte Silver | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐ | —— |
| Ni (Nickel) | 5-15 µm | Bright Silver | ⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐ |
| Epoxy | 15-30 µm | Black, multi-color possible | ⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐ | ⭐⭐⭐⭐ |
| Zn-Al | 8-20 µm | Silver-grey/Grey | ⭐⭐⭐⭐ | ⭐⭐⭐⭐⭐ | ⭐⭐⭐⭐ | —— | ⭐⭐⭐⭐⭐ |
| Al (Aluminum) | 10-30 µm | Matte Silver-grey | ⭐⭐⭐ | ⭐⭐⭐ | ⭐⭐⭐⭐ | —— | ⭐⭐⭐⭐ |
Notes:
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Star Rating: ⭐ (Poor) to ⭐⭐⭐⭐⭐ (Excellent). “-” indicates Not Applicable or not a primary evaluation parameter. Ratings are relative comparisons; actual performance depends on specific process, thickness, and test conditions.
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PCT: Pressure Cooker Test, simulates high-temperature, high-humidity environments.
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Salt Spray: Neutral Salt Spray (NSS) test, evaluates corrosion resistance. Higher stars indicate longer endurance times.
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Damp-heat: Constant or Cyclic Damp Heat test, evaluates stability under high temperature and humidity.
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Acid & Alkali Resistance: Resistance to common weak acids and bases. Most coatings are damaged by strong acids/bases.