Repumag Magnetic Materials Co.,Ltd.

NdFeB Magnets

Neodymium magnets can be divided into three main groups:
1.Regular Neodymium Magnets
2.High corrosion resistant Neodymium Magnets
3.Bonded Neodymium (Isotropic): Manufactured by the injection of plastic material and Neodymium into a mold. This production method yields a very precise magnet which does not require further grinding and does not suffer substantial current loss.

High Corrosion Resistant Magnets

Under the Environment of high temperature, high pressure and high humidity, the weight loss level of uncoated magnets can qualitatively reflect its serving life clearly. Referring to the standard IEC68-2-66 and after 20 days, Hast testing, weight loss of less than 2mg/cm² is available for Repumag, which is the top level worldwide.

Weight loss of Repumag in a Hast-Test ( 130℃, 95% relative humidity 2.7bar in vapor)？

Glued NdFeB Magnets

NdFeB magnets could be glued in any sizes depends on customers requests, there is a max Isolation Resistance requests, glue gap thickness etc, and how to test the isolation resistance as below.

Advantages and Disadvantages

Advantages and Disadvantages of NdFeB Permanent Magnets

1) Is the strongest magnetic of permanent magnets, has the high energy (BH value) and good coercive force.
2) Manufacturing by the the vacuum sintering process, process maturity;small dimensions,have the good performances and prices; energy (BH value) of NdFeB magnets is more than ten times higher than Ferrites, it is the strongest magnetic materials in the world today, have “magnetic king”reputation.
3) Using the cutting process after sintering,according to the requirements,by the rapid processing, they can be cutted into square,disc.,ring,segment(like tile shape),and so on;Dimension tolerance is commonly +/-0.05mm,if special request,it can be controlled within 0.05mm range by increasing grinding; If requesting the higher process,using the fast quenching scales manufacturing Nd-Fe-B binding NdFeB1988,the repumag of dimensions can be reached 0.01mm,but because the organic binder content cause the low energy product,and the much higher cost of forming dies.
4) NdFeB permanent magnets are easy to be rusted/oxided, so their surface should be done eletroplating treatment, such as galvanized(Zn coating), Nickel+copper+nickel, and so on, generally, it requests more than 48hours in Salt-spray test; also can be passivated treament to slow down its oxidative speed; if using the vacuum plating aluminum + electrophoresis epoxy resin, it can go through more than 96hours in Salt-spray condition.

Comparison Permanent Magnets

Basic Performance Comparison Table of Permanent Magnets

Magnets	BHmax（MGOe）	Max.Working Temp.(0C)	Corrosion Resistance	Magnetic Performance	Material Price	Coercive Force	Processing Charateristics	Composite Index
Sintered NdFeB	26-52	≤200	C	A+	B-	A+	B+	70
SmCo 2:17	22-30	≤300	A	A	C-	A	C	64
SmCo 1: 5	16-25	≤250	A	A-	C	A-	C	62
Bonded NdFeB	5/12	<150	B-	B	C	A+	-	68
AlNiCo	<10	<550	A+	B	B	C-	C	54
Sintered Ferrite	3-4.5	< 350	A	C	A	B-	B	64
Bonded Ferrite	2-3	< 150	A	C	B	B-	-	66
Rubber	0.7/1.6	<85	B	C	B+	C	A	56

Magnetic Properties

Grade	Br				HcB		Hcj		(BH )max				Max Working Temperature
	KGs		T		KOe	KA/m	KOe	KA/m	MGOe		KJ/m 3		L/D=0.7
	Max	Min	Max	Min	Min	Min	Min	Min	Max	Min	Max	Min	℃
N33	11.8	11.3	1.18	1.13	≥10.5	≥836	≥12	≥955	34	31	271	247	≤80
N35	12.3	11.8	1.23	1.18	≥10.9	≥866	≥12	≥955	36	33	287	263	≤80
N38	12.6	12.3	1.26	1.23	≥11.3	≥899	≥12	≥955	39	36	311	287	≤80
N40	12.9	12.6	1.29	1.26	≥11.4	≥90	≥12	≥955	41	38	327	302	≤80
N42	13.3	12.9	1.33	1.29	≥11.5	≥915	≥12	≥955	43	40	342	318	≤80
N45	13.7	13.3	1.37	1.33	≥11.0	≥876	≥12	≥955	46	43	366	342	≤80
N48	14.1	13.7	1.41	1.37	≥10.5	≥836	≥11	≥876	49	45	390	358	≤80
N50	14.5	14.0	1.45	1.40	≥10.5	≥836	≥11	≥876	51	47	406	374	≤60
N52	14.8	14.3	1.48	1.43	≥10.5	≥836	≥11	≥876	53	49	422	390	≤60
30M	11.3	10.8	1.13	1.08	≥10	≥796	≥14	≥1114	31	28	247	223	≤100
33M	11.8	11.3	1.18	1.13	≥10.5	≥836	≥14	≥1114	34	31	271	247	≤100
35M	12.3	11.8	1.23	1.18	≥10.9	≥868	≥14	≥1114	36	34	287	271	≤100
38M	12.6	12.3	1.26	1.23	≥11.3	≥899	≥14	≥1114	39	36	311	287	≤100
40M	12.9	12.6	1.29	1.26	≥11.6	≥923	≥14	≥1114	41	38	327	302	≤100
42M	13.3	12.9	1.33	1.29	≥12	≥955	≥14	≥1114	43	40	342	318	≤100
45M	13.7	13.3	1.37	1.33	≥12.5	≥995	≥14	≥1114	46	43	366	342	≤100
48M	14.1	13.7	1.41	1.37	≥12.9	≥1027	≥14	≥1114	49	45	390	358	≤100
50M	14.5	14.0	1.45	1.40	≥13	≥1033	≥14	≥1114	51	47	406	374	≤100
30H	11.3	10.8	1.13	1.08	≥10	≥796	≥17	≥1353	31	28	247	223	≤120
33H	11.8	11.3	1.18	1.13	≥10.5	≥836	≥17	≥1353	34	31	271	247	≤120
35H	12.3	11.8	1.23	1.18	≥10.9	≥868	≥17	≥1353	36	33	287	263	≤120
38H	12.6	12.3	1.26	1.23	≥11.3	≥899	≥17	≥1353	39	36	311	287	≤120
40H	12.9	12.6	1.29	1.26	≥11.6	≥923	≥17	≥1353	41	38	327	302	≤120
42H	13.3	12.9	1.33	1.29	≥12	≥955	≥17	≥1353	43	40	342	318	≤120
45H	13.7	13.3	1.37	1.33	≥12.3	≥979	≥17	≥1353	46	43	366	342	≤120

Grade	Br				HcB		Hcj		(BH )max				Max Working Temperature
	KGs		T		KOe	KA/m	KOe	KA/m	MGOe		KJ/m 3		L/D=0.7
	Max	Min	Max	Min	Min	Min	Min	Min	Max	Min	Max	Min	℃
48H	14.1	13.7	1.41	1.37	≥12.5	≥995	≥17	≥1353	49	46	390	366	≤120
30SH	11.4	10.8	1.14	1.08	≥10.1	≥804	≥20	≥1592	31	28	247	223	≤150
33SH	11.8	11.4	1.18	1.14	≥10.6	≥844	≥20	≥1592	34	31	271	247	≤150
35SH	12.3	11.8	1.23	1.18	≥11.0	≥876	≥20	≥1592	36	33	287	263	≤150
38SH	12.6	12.3	1.26	1.23	≥11.4	≥907	≥20	≥1592	39	36	311	287	≤150
40SH	12.9	12.6	1.29	1.26	≥11.6	≥939	≥20	≥1592	41	38	326	302	≤150
42SH	13.3	12.9	1.33	1.29	≥12.4	≥987	≥20	≥1592	43	40	342	318	≤150
45SH	13.7	13.2	1.37	1.32	≥12.6	≥1003	≥20	≥1592	46	42	366	334	≤150
28UH	10.8	10.4	1.08	1.04	≥9.6	≥764	≥25	≥1989	29	26	231	207	≤180
30UH	11.4	10.8	1.14	1.08	≥10.1	≥804	≥25	≥1989	31	28	247	223	≤180
33UH	11.8	11.4	1.18	1.14	≥10.7	≥852	≥25	≥1989	34	31	271	247	≤180
35UH	12.3	11.8	1.23	1.18	≥10.8	≥860	≥25	≥1989	36	33	287	263	≤180
38UH	12.6	12.3	1.26	1.23	≥11.3	≥899	≥25	≥1989	39	36	311	287	≤180
40UH	12.9	12.5	1.29	1.25	≥11.3	≥899	≥25	≥1989	41	38	326	302	≤180
42UH	13.3	12.8	1.33	1.28	≥11.6	≥923	≥25	≥1989	43	40	342	318	≤180
28EH	10.8	10.4	1.08	1.04	≥9.8	≥780	≥30	≥2388	29	26	231	207	≤200
30EH	11.4	10.8	1.14	1.08	≥10.1	≥804	≥30	≥2388	31	28	247	223	≤200
33EH	11.8	11.4	1.18	1.14	≥10.3	≥820	≥30	≥2388	34	31	271	247	≤200
35EH	12.3	11.7	1.23	1.17	≥10.5	≥836	≥30	≥2388	36	33	287	263	≤220
38EH	12.6	12.2	1.26	1.22	≥11.3	≥899	≥30	≥2388	39	35	311	278	≤220
28AH	10.9	10.4	1.09	1.04	≥9.8	≥780	≥35	≥2785	29	33	231	207	≤230
30AH	11.3	10.8	1.13	1.08	≥10.1	≥804	≥35	≥2785	31	26	247	223	≤230
33AH	11.8	11.3	1.18	1.13	≥10.3	≥820	≥33	≥2625	34	28	271	247	≤230
35AH	12.3	11.7	1.23	1.17	≥10.5	≥860	≥33	≥2625	36	33	287	263	≤230

Special Propertv Data

Grade	Item	(Lost percent when heat up %/℃)（20℃～1 50℃）		(Lost weight standard)mg/cm2
Grade	Item	Br	Hcj	(Lost weight standard)mg/cm2
Normal Grade		-(0.1 1 ~0.1 2)	-(0.58~0.70)	≤80
"T"Grade1		-(0.095~0.1 1 5)	-(0.46~0.59	≤15
"L"Grade2 "		-(0.1 0~0.1 2)	-(0.55~0.65)	≤5
"TL"Grade3		-(0.095~0.1 1 5)	-(0.46~0.59)	≤5

Remark ：
1） “T” grade seris product can be better temperature performance, and it could be used from "H" grade like 45HT、35SHT、38UHT;
2） “L” rade seris product can be better lost weight performance, and our lost weight test standard is 1 21℃ 2atm 95％Humidity，168hours；
3） “TL” rade seris product have both the "L" and "T" grade.

Physical Property

Parameter	Unit	Reference Value
Vickers hardness	Hv	≥550
Density	g/cm3	≥7.40
RecalPenmeability μr	＼	1.05
Curie point Tc	＼℃	312~380
Specific resistance	μ Ω ·cm	150
Bending strength	MPa	250
Compressive strength	MPa	1000~1100
Thermal expansion (⊥)	℃－1	-~3)×10－6K
Thermal expansion ( // ）	℃－1	-~4)×10－6K

NdFeB Curves

Magnetic Properties

Item	Inspecting method	Inspecting standard
Magnetic performance	GB/T 13560-2000	GB/T3217-92
Weightlessness rate	Test cases with constant temperature & constant pressure ,96hrs ,（130±2℃（0.27MPa）	Normal products ：≤50mg/cm2 ； Low weight-loss products ：≤10mg/cm2
Density	Drainage method for measuring	7.4-7.6g/ cm3
ROHS requirements	Equivalent to use the green purchasing standards CS-K1100 (2 edition) in SANYO
Mechanical performance index
	Hardness: 570HV	Fracture toughness ：2.5-5 Mpam2
	Resistivity：150μΩ·cm	Specific heat：0.502 Kj· (kg·℃
	Compressive strength：780 N/mm2	Thermal conductivity ：8.9551 w/m·K
Bending strength ：290 Mpa	Thermal expantion coefficient(in vertical orientation direction)：-4.8X10-6K

NdFeB Magnets Magnetization

NdFeB Coating

On the basis of producing high quality raw blocks, Repumag has been researching and developing updated surface protection technology vigorously. We can provide customers with high quality coatings and humidity resistance of coated magnets are quite good to assure magnets safe enough even in rigorous environments.

During the process of coating and plating, Repumag Magtch attaches great importance to environment protection, all coatings meet the requirements of ROHS.

Neo magnets are known for their high temperature resistance, making them durable and functional in temperatures exceeding 200°C. This quality makes them ideal for heavy industry applications. Sintered Neodymium, however, is sensitive to oxidization and can develop corrosion, so magnets are usually coated with Nickel+Copper+Nickel,Nickel+Sn, Zn(galvanization), Epoxy and Passivation for their protection.

Type	Thickness	Colour	Temperature	PCT	SST	Characteristic
Zn	5-10μm	Blue Silver	≤160℃	—	＞48hr	protection for most products
Ni＋Sn	10-30μm	Semibright Silver	≤160℃	＞48hr	＞96hr	excellent climate&salt spray resistance
Ni	10-30μm	Blue Silver	≤200℃	＞48hr	＞96hr	excellent climate&salt spray resistance , suitable for clean-room
Al Spraying	6-20μm	Dark Silver	≤200℃	—	＞288hr	superior resistance to salt &humid atmosphere suitable for big size or anomalous magnets
IVD Al	10-30μm	Silver White	≤400℃	＞48hr	＞288hr	superior resistance to salt&humid atmosphere , thickness equality , excellent adhesive attraction
Epoxy	10-30μm	Black Gray	≤120℃	＞48hr	＞96hr	well climate&salt spray resistance

Dimension (mm)	Tolerance (mm)	Parallelism (mm)	Perpendicularity
L≤10	±0.03	0.04	0.5 degree for adjacent sides
10＜L≤25	±0.03	0.06
25＜L≤63	±0.04	0.10
L＞63	±0.06	0.12

OD Dimension (mm)	Tolerance (mm)	Cylindricitym (mm)	Circular Run-out (mm)
D≤10	±0.02	0.03	0.08
10＜D≤25	±0.02	0.03	0.08
D＞25	±0.03	0.04	0.10

Item	Dimension (mm)	Tolerance (mm)
Thickness	T≤10	±0.04
Thickness	10＜T≤25	±0.05
Length	L≤10	±0.03
	10＜T≤25	±0.03
	25＜T≤63	±0.04
L＞63	±0.06
Chordal Length	W≤63	±0.05
Chordal Length	W＞63	±0.06

ID Dimension (mm)	Tolerance (mm)	Coaxiality (mm)
d≤3	±0.04	0.06
3＜d≤6	±0.05	0.06
d＞6	±0.05	0.10

NdFeB Magnets

High Corrosion Resistant Magnets

Glued NdFeB Magnets

Advantages and Disadvantages

Comparison Permanent Magnets

Magnetic Properties

NdFeB Curves

Magnetic Properties

NdFeB Magnets Magnetization

NdFeB Coating

Machining Capacity

A, Dimensions and Shapes

B, Tolerances

Applications

Packing of NdFEB magnets