钕铁硼圆柱
简述
烧结钕铁硼永磁材料采用的是粉末冶金工艺，熔炼后的合金制成粉末并在磁场中压制成压胚，压胚在惰性气体或真空中烧结达到致密化而成。烧结钕铁硼永磁材料具有优异的磁性能，广泛应用于电子、电力机械、医疗器械、玩具、包装、五金机械、航天航空等领域，较常见的有永磁电机、扬声器、磁选机、计算机磁盘驱动器、磁共振成像设备仪表等。最高工作温度可达250℃；机械性能亦相当好，可以适合磨、线切割和钻孔等不同的加工方式；由于抗腐蚀性差，所以根据不同要求必须对表面进行不同的凃层处理(如镀Zn,Ni,Au,Epoxy等)。
磁铁硼如何制造
钕铁硼磁铁主要由钕，铁，硼，钴，镝，镨等合金组成。
钕铁硼不同的化学成份决定了钕铁硼的性能档次。加入镝和镨提高磁铁的耐腐蚀性和钕铁硼磁铁的矫顽力。下面是一个例子供参考：
制造钕铁硼磁铁方法如下：
钕金属最初是从精练稀土氧化物的电解炉中分离出来。“稀土“是镧系元素，虽然史称叫做”稀土“，但不等于这是一种稀缺矿物质，稀土元素中的钕是比黄金更常见。钕，铁和硼提炼出来后再按一定比例混全放入真空炉，并熔合成一种合金。再根据特定的等级加入不同的元素如钴，铜，钆和镝。再高频加热和熔化成混合物。
1. 原料提炼：高纯度的稀土金属从氧化物中提炼出来。
2. 原料混合：原料（钕，铁，钴等等）按一定比例混合。
3. 熔炼：在真熔炼炉中熔成合金锭。
4. 制粉： 把合金块粉碎成细粉。
5. 成型：磁场中压制成型各种形状。
6. 烧结：成型好的坯料在烧结炉中烧结。
7. 磁性检测：性能参数检测，合格进下一道工序。
8. 机械加工：机械加工成各种尺寸。
9. 表面处理： 产品表面（ZN, NI等等）处理，防止生锈。
10. 外观检测：外观及公差检测。
11. 磁化：产品充磁。
12. 出货：包装运输。
钕铁硼的材料牌号
| GRADE | (Br) | (bHc) | (iHc) | (BH)max | Tw ℃ | ||||
|---|---|---|---|---|---|---|---|---|---|
| T | KGs | KA/m | KOe | KA/m | KOe | KJ/m3 | MGOe | ||
| N35 | 1.18-1.23 | 11.8-12.3 | ≥868 | ≥10.9 | ≥955 | ≥12 | 263-287 | 33-36 | ≤80 |
| N38 | 1.22-1.28 | 12.2-12.8 | ≥899 | ≥11.3 | ≥955 | ≥12 | 287-310 | 36-39 | ≤80 |
| N40 | 1.26-1.31 | 12.6-13.1 | ≥923 | ≥11.6 | ≥955 | ≥12 | 302-326 | 38-41 | ≤80 |
| N42 | 1.28-1.34 | 12.8-13.4 | ≥923 | ≥11.6 | ≥955 | ≥12 | 318-342 | 40-43 | ≤80 |
| N45 | 1.32-1.37 | 13.2-13.7 | ≥876 | ≥11.0 | ≥955 | ≥12 | 342-366 | 43-46 | ≤80 |
| N48 | 1.36-1.42 | 13.6-14.2 | ≥836 | ≥10.5 | ≥876 | ≥11 | 358-390 | 45-48 | ≤80 |
| N50 | 1.39-1.45 | 13.9-14.5 | ≥836 | ≥10.5 | ≥876 | ≥11 | 374-406 | 47-51 | ≤80 |
| N52 | 1.42-1.48 | 14.2-14.8 | ≥796 | ≥10.0 | ≥876 | ≥11 | 390-422 | 49-53 | ≤80 |
| N35M | 1.18-1.23 | 11.8-12.3 | ≥868 | ≥10.9 | ≥1114 | ≥14 | 263-287 | 33-36 | ≤100 |
| N38M | 1.22-1.28 | 12.2-12.8 | ≥899 | ≥11.3 | ≥1114 | ≥14 | 287-310 | 36-39 | ≤100 |
| N40M | 1.26-1.31 | 12.6-13.1 | ≥923 | ≥11.6 | ≥1114 | ≥14 | 302-326 | 38-41 | ≤100 |
| N42M | 1.28-1.34 | 12.8-13.4 | ≥923 | ≥11.6 | ≥1114 | ≥14 | 318-342 | 40-43 | ≤100 |
| N45M | 1.34-1.39 | 13.4-13.9 | ≥876 | ≥11.0 | ≥1114 | ≥14 | 342-366 | 43-46 | ≤100 |
| N48M | 1.36-1.42 | 13.6-14.2 | ≥876 | ≥11.0 | ≥1114 | ≥14 | 366-390 | 46-49 | ≤100 |
| N35H | 1.18-1.23 | 11.8-12.3 | ≥868 | ≥10.9 | ≥1353 | ≥17 | 263-287 | 33-36 | ≤120 |
| N38H | 1.22-1.28 | 12.2-12.8 | ≥899 | ≥11.3 | ≥1353 | ≥17 | 287-310 | 36-39 | ≤120 |
| N40H | 1.26-1.31 | 12.6-13.1 | ≥923 | ≥11.6 | ≥1353 | ≥17 | 302-326 | 38-41 | ≤120 |
| N42H | 1.28-1.34 | 12.8-13.4 | ≥923 | ≥11.6 | ≥1353 | ≥17 | 318-342 | 40-43 | ≤120 |
| N45H | 1.33-1.39 | 13.3-13.9 | ≥923 | ≥11.6 | ≥1353 | ≥17 | 342-366 | 43-46 | ≤120 |
| N48H | 1.36-1.42 | 13.6-14.2 | ≥923 | ≥11.6 | ≥1274 | ≥16 | 366-390 | 46-49 | ≤120 |
| N33SH | 1.14-1.19 | 11.4-11.9 | ≥836 | ≥10.5 | ≥1592 | ≥20 | 247-270 | 31-34 | ≤150 |
| N35SH | 1.18-1.23 | 11.8-12.3 | ≥868 | ≥10.9 | ≥1592 | ≥20 | 263-287 | 33-36 | ≤150 |
| N38SH | 1.22-1.28 | 12.2-12.8 | ≥899 | ≥11.3 | ≥1592 | ≥20 | 287-310 | 36-39 | ≤150 |
| N40SH | 1.26-1.31 | 12.6-13.1 | ≥923 | ≥11.6 | ≥1592 | ≥20 | 302-326 | 38-41 | ≤150 |
| N42SH | 1.28-1.34 | 12.8-13.4 | ≥923 | ≥11.6 | ≥1592 | ≥20 | 318-342 | 40-43 | ≤150 |
| N45SH | 1.33-1.39 | 13.3-13.9 | ≥923 | ≥11.6 | ≥1592 | ≥20 | 342-366 | 43-46 | ≤150 |
| N28UH | 1.03-1.09 | 10.3-10.9 | ≥780 | ≥9.80 | ≥1990 | ≥25 | 207-231 | 26-29 | ≤180 |
| N30UH | 1.09-1.14 | 10.9-11.4 | ≥812 | ≥10.2 | ≥1990 | ≥25 | 223-247 | 28-31 | ≤180 |
| N33UH | 1.13-1.17 | 11.3-11.7 | ≥852 | ≥10.7 | ≥1990 | ≥25 | 247-263 | 31-33 | ≤180 |
| N35UH | 1.18-1.22 | 11.8-12.2 | ≥868 | ≥10.9 | ≥1990 | ≥25 | 263-287 | 33-36 | ≤180 |
| N38UH | 1.22-1.27 | 12.2-12.7 | ≥899 | ≥11.3 | ≥1990 | ≥25 | 287-310 | 36-39 | ≤180 |
| N28EH | 1.03-1.09 | 10.3-10.9 | ≥780 | ≥9.80 | ≥2388 | ≥30 | 207-231 | 26-29 | ≤200 |
| N30EH | 1.08-1.13 | 10.8-11.3 | ≥812 | ≥10.2 | ≥2388 | ≥30 | 223-247 | 28-31 | ≤200 |
| N33EH | 1.13-1.17 | 11.3-11.7 | ≥852 | ≥10.7 | ≥2388 | ≥30 | 247-263 | 31-33 | ≤200 |
| N35EH | 1.18-1.22 | 11.8-12.2 | ≥868 | ≥10.9 | ≥2388 | ≥30 | 263-287 | 33-36 | ≤200 |
| N28AH | 1.03-1.09 | 10.3-10.9 | ≥780 | ≥9.80 | ≥2786 | ≥35 | 207-231 | 26-29 | ≤220 |
| N30AH | 1.08-1.13 | 10.8-11.3 | ≥812 | ≥10.2 | ≥2786 | ≥35 | 223-247 | 28-31 | ≤220 |
钕铁硼的各种镀层
| Surface | Coating | Thickness (Microns) |
Color | Resistance |
|---|---|---|---|---|
| Passivation | 1 | Silver Grey | Temporary Protection | |
| Nickel | Ni+Ni | 10--20 | Bright Silver | Excellnet Against Humidity |
| Ni+Cu+Ni | ||||
| Zinc | Zn | 8--20 | Bright Blue | Good Against Salt Spray |
| C-Zn | Shinny Color | Excellnet Against Salt Spary | ||
| Tin | Ni+Cu+Sn | 15--20 | Silver | Superior Against Humidity |
| Gold | Ni+Cu+Au | 10--20 | Gold | Superior Against Humidity |
| Copper | Ni+Cu | 10--20 | Gold | Temporary Protection |
| Epoxy | Epoxy | 15--25 | Black,Red,Grey | Excellent Against Humidity & Salt Spary |
| Ni+Cu+Epoxy | ||||
| Zn+Epoxy | ||||
| Chemical | Ni | 10--20 | Silver Grey | Excellent Against Humidity |
| Parylene | Parylene | 5--20 | Grey | Excellent Against Humidity,Salt Spray. Superior Against Solvents,
Gases, Fungi and Bacteria. FDA Approved. |
永磁钕铁硼的物理特性
钕铁硼磁铁牌号比较多， 每个牌号都有其自己的物理特性（与磁场输出和抗消磁的强度，最大工作温度和温度系数）。
下面是列出了每个牌号相似的物理性能：
|
Characteristic |
Symbol |
Unit |
Value |
|
Density |
D |
g/cc |
7.5 |
|
Vickers Hardness |
Hv |
D.P.N |
570 |
|
Compression Strength |
C.S |
N/mm2 |
780 |
|
Coefficient of Thermal Expansion |
C// |
10-6/°C |
3.4 |
|
|
C^ |
10-6/°C |
-4.8 |
|
Electrical Resistivity |
r |
m Ω.cm |
150 |
|
Temperature Coefficient of Resistivity |
a |
10-4/°C |
2 |
|
Electrical Conductivity |
s |
106S/m |
0.667 |
|
Thermal Conductivity |
k |
kCal/(m.h.°C) |
7.7 |
|
Specific Heat Capacity |
c |
kCal/(kg.°C) |
0.12 |
|
Tensile Strength |
σUTS, or SU |
kg/mm2 |
8 |
|
Young's Modulus |
l / E |
1011N/m2 |
1.6 |
|
Flexural Strength |
b |
10-12m2/N |
9.8 |
|
Compressibility |
s |
10-12m2/N |
9.8 |
|
Rigidity |
E.I |
N/m2 |
0.64 |
|
Poisson's Ratio |
n |
|
0.24 |
|
Curie Temperature |
Tc |
°C |
310 |