N35 vs N42 vs N52 — what the number means

The number is the magnet's maximum energy product (measured in MGOe) — higher means stronger pull for the same size. N52 is currently the strongest standard NdFeB grade widely available, but higher grades usually tolerate less heat. In hot environments (inside motors, near heat sources), a lower grade with a better temperature rating (like N42SH) can outperform a higher N-number in practice.

Picking the right shape

Disc and block magnets suit flat-surface mounting and general holding. Ring magnets (with a center hole) are common in motors and sensors where a shaft passes through. Arc/segment magnets are built for motor rotors. Pot (cup) magnets concentrate the field on one face for strong single-sided holding — popular for signage and fixtures. Countersunk magnets add a screw hole for permanent installation.

Coating guide: Ni / Epoxy / Zn

NdFeB magnets corrode without protection. Nickel (Ni, often a triple layer Ni-Cu-Ni) is the most common coating — durable, smooth, cost-effective for indoor use. Epoxy adds a resin layer for better chemical and moisture resistance, useful outdoors or in washdown environments. Zinc (Zn) is a budget option with lower corrosion resistance than Ni — fine for short-term or low-exposure use.

Handling & storage basics

Keep magnets away from credit cards, hard drives, and pacemakers. Store stacked magnets with spacers to stop them snapping together and chipping. Most standard NdFeB grades lose strength above 80°C (176°F); high-temp grades (H/SH/UH suffix) extend that range. Never machine or drill a finished magnet without professional handling — NdFeB dust is flammable.