Magfine Corporation is the best magnet company with 25 years in business
Comparison of coating performance Below is a comparison of the performance of various coating materials used on neodymium magnets. It is important to take into consideration the usage environment when choosing the coating as the properties of the magnet will change depending on the type of coating.
| Material | Code | Thickness(μm) | Corrosion resistant salt spray (Hr) | Porosity | Demagnetization rate | Abstract colors | PCT(Hr) |
|---|---|---|---|---|---|---|---|
| Hi-Den Coat MF304 Epoxy | MF304 Epoxy | 5-100 | >500 | - | - | Multi-colors | >100 |
| MF305 Polyimide | MF305 Polyimide | 5-50 | >400 | - | - | Multi-colors | >100 |
| Zinc | Zn | 10-15 | >24 | <0.1 | <0.2% | White | >16 |
| Coloured zinc | Colour-Zn | 10-15 | 72 | <0.1 | <0.1% | Multi-colors | >24 |
| Nickel | Ni | 10-20 | 4 | <0.5 | <0.3% | Silver | >16 |
| Double nickel | Double-Ni | 15-20 | 24 | <0.2 | <0.3% | Silver | >16 |
| Nickel-copper-nickel | Ni-Cu-Ni | 15-30 | >48 | <0.1 | <0.1% | Silver | >42 |
| Zinc-nickel-alloy | Zn-Ni Alloy | 10-20 | >720 | <0.1 | <0.1% | Multi-colors | >72 |
| Other company's Epoxy | EPOXY | 10-50 | >300 | - | - | Black | >24 |
| Electroless Nickel | Electroless Ni | <1 | >72 | - | - | Silver | >24 |
Types of plating for magnets
| Element symbol | Name of element | φ10mm×10mm | Properties | Usage |
|---|---|---|---|---|
| 3CrZn | Trivalent chromium zinc |
 |
Chromate treatment. Recently hexavalent chromium has been regulated as an environmentally destructive substance and replaced with trivalent chromium |
|
| Ag | Silver |  |
Silver has the best electric conductivity out of all the metals, low contact resistance and good solderability but is easy to discolor. |
|
| Au | Gold |  |
Gold has good corrosion and oxidation resistance along with low electrical resistance. |
|
| Cr | Chrome |  |
Chrome has good abrasion and oxidation resistance and will not lose its shine in the atmosphere. |
|
| Cu | Copper |  |
Copper is easy to discolor so is used as a base. It is used to fill in dents and bring out a shine. |
|
| Ni | Nickel |  |
Nickel is chemically stable and has good anti-rust properties. It can be used for a wide range of purposes and is used as a base for gold plating, chrome plating etc. It can cause skin irritation. |
|
| NiBlack | Black nickel |  |
Black nickel is an alloy plating made of nickel, zinc and sulphur. The color may vary depending on the type of plating used as a base. |
|
| Sn | Tin |  |
Tin has excellent anti-corrosion properties and does not oxidize easily. It does not lose its shine easily and is safe to use in foods. |
|
| Rh | Rhodium |  |
Rhodium has excellent anti-corrosion properties and does not oxidize easily. It does not lose its shine easily and is safe to use in foods. |
|
| - | Un-treated |  |
No surface treatment coating. Rust will develop easily on neodymium magnets. |
Anti-rust properties test
| Magfine | Company S | Other companies | Magfine | Company T | Magfine | |
|---|---|---|---|---|---|---|
| Duration | HDCcoating epoxy MF304 |
Normal epoxy | Anti-rust undercoat Zn for automobiles | HDC coating polyimide MF305 |
Normal epoxy | NiCuNi |
| Before start of test |  |
|||||
| After 72 hrs |  |
|||||
| After 312 hrs |  |
|||||
| After 504 hrs |  |
|||||
Neutral salt spray test 5% sodium chloride solution test temperature 35℃ JIS Z2371
Comparison chart of surface treatment
| Electric plating | Thermal spraying | Deposition | Electrodeposition | Parylene coating | Hi-DEN COAT | |
|---|---|---|---|---|---|---|
| Process | Wet | Dry | Dry | Wet | Dry | Dry |
| Selection of object to be coated | Large objects are difficult | Large objects are difficult | No problem | Small objects are difficult | Large objects are difficult | No restrictions |
| Deposition speed | Slow | Fast | Slow(limited) | Fast | Slow | Slow |
| Deposition adhesion | Strong | Strong | Weak | Strong | Weak | Strong |
| Hydrogen embrittlement | Potential risk | None | None | Potential risk | None | None |
| Effect on environment | Very large | Small | Small | Small | Small | Small |
| Adherend strength | Weak | Very weak | Weak | Strong | Weak | Strong |
| Choice of color | Only metal colors | None | Only metal colors | Fairly large | None | Fairly large |
| Insulation | Only certain materials | Only certain materials | Only certain materials | Yes | Yes | Yes |
| Machining after processing | Not possible | Not possible | Not possible | - | Not possible | Possible |
| Productivity | Good | Difficult | Difficult | Good | Good | Good |
| Addition of modifying material (Specific to properties of various types) |
Not possible | Not possible | Not possible | Not possible | Not possible | Possible |
磁石のコンテンツ終点
