Black Plastic Coated Neodymium Ring Magnet - 77mm (OD) x 8mm (ID) x 17mm (H) I 6 Multi-Poled
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This high-strength Neodymium Ring Magnet (N45) features an outer diameter of 77mm, an inner diameter of 8mm, and a height of 17mm. It is axially magnetised with a 6-multipole configuration, enhancing its efficiency in specialised applications. The black plastic coating provides durability, corrosion resistance, and a smooth surface for easy handling.
Ideal for Prawn Farming & Artemia Separation
This neodymium ring magnet is widely used in prawn farms to efficiently separate Artemia (brine shrimp) from their casings. Its strong multi-poled magnetic field attracts and retains non-nutritious cyst shells, ensuring a cleaner and higher-quality feed for aquatic species.
Designed for harsh marine environments, the protective plastic coating enhances longevity by shielding the magnet from moisture and chemical exposure. Whether used in hatcheries or large-scale aquaculture, this magnet provides a reliable, non-invasive solution for improving feed quality and reducing waste.
Rough Pull Force Estimate
For a single-pole, axially magnetised neodymium ring magnet of similar size (without multi-pole magnetisation), the pull force would typically range from 80–120 kg when in direct contact with a thick ferrous surface.
However, because this magnet is multi-pole, the force is distributed across multiple poles instead of being concentrated at one surface. This generally reduces the direct pull force but improves lateral gripping strength and efficiency in applications like Artemia separation.
Estimated Pull Force:
- Direct contact with a thick steel plate: ~50–80 kg (adjusted for multi-pole effect).
- Pull force at a small air gap (1-2mm): ~30–50 kg (plastic coating increases the gap).
- Shear force (lateral strength for holding/sliding applications): Potentially higher due to multiple poles improving grip.
Typical Physical Properties
NB: Ranges are indicative for product category, please check individual products for specic values within that range.
Production Flow Diagram
Demagnetization Curves
Surface Treatment
The most common coating for Neodymium magnets is Nickel + Copper + Nickel (Ni + Cu + Ni). This coating offers the magnet relatively good protection from corrosion and passive applications. If the magnet will be exposed to moisture or liquid then consider the use of an organic coating such as Epoxy. A hard wearing coating, Epoxy is suited to applications where the magnet will come under some friction or knocking.
Range and Tolerance
Magnets are readily available in Blocks, Discs, Cylinders & Rings. AMF Magnetics specializes in the supply of short-run prototype magnets including Arc Segments, various magnetic orientations etc. If you need a magnet size that we don't carry in stock, submit a Design-a-Magnet enquiry for a quote on your custom magnet design.
Magnetic Properties
Neodymium magnets are offered in several different grades. The first section N30-54 has an operating temperature of up to 80 degrees. Most of our stock only goes up to N38. The second section, denoted with the "M" prefix after the grade has an operating temperature 100 degrees. After this the grades are "H", "SH", "UH" & "EH". In order for the magnet to withstand a higher operating temperature, during production more of the raw material PrNd is incorporated as these elements have a naturally occurring resistance to high temperatures.
Returns Policy
If you are not entirely satisfied with your purchase, we're here to help.
We have a 30 Day Returns policy at Frenergy Magnets. You may return your item within 30 days of receiving it to receive a refund.
The product/s must be unused and in the same condition you received them in. Please contact us at info@frenergy.com.au to initiate the returns process.
The buyer is responsible for the cost of returning the order.
