Advantages of Single
Crystal products in comparison with ones manufactured by
using conventional technologies:
-
Extended temperature and time stability
-
Improved magnetic parameters in comparison
with cast and columnar magnets by 20-100%
-
High uniformity of properties
-
Opportunity to manufacture four-pole
magnets
-
Opportunity to manufacture magnet blanks
of big sizes (to 50 mm diameter and to 200 mm length)
and complicated shapes
-
Increased efficiency
of magnets by 20% and magnet
flux in a gap of DC motors - by 30%
-
Decreased power consumption at simultaneous
increasing maximum capacity of motor of the same sizes
by 1.5-2 times
-
Applied to brushless motors, these
magnets result in twice as much capacity
Magnetic and other physical-mechanical properties:
| Parameter |
Alnico 8AA (AlNiCoTi5A)
|
Alnico 9AA (AlNiCoTi8AA)
|
FeCoCrMo (FeCr22Co18Mo4)
|
| Residual induction, Br,T |
1.05 - 1.15
|
0.9 – 0.95
|
1.4 – 1.5
|
| Coercitivity, Hcb, kA/m |
115 - 120
|
145 - 160
|
65 - 70
|
| Energy product, (BH)max, kJ/m3 |
80.0 – 90.0
|
64.0 –72.0
|
72.0 – 80.0
|
| Density, g/cm3 |
7.3
|
7.4
|
7.5
|
| Thermal conductivity, at 20-300oC, W/moK
|
20.5/23.9
|
20.5/23.9
|
|
| Linear expansion coefficient at 20-300oC,
x 1061/oK |
11.0
|
10.8
|
12.2
|
| Ultimate strength at tension, MPa |
120
|
120
|
2000
|
| Ultimate strength at bending, MPa |
200
|
200
|
|
| Ultimate strength at compression, MPa
|
1250
|
1250
|
1700
|
| Impact toughness, kJ/m2 |
0.15-0.20
|
0.15-0.20
|
1.0
|
| Temperature coefficient of induction,
%/K |
0.0005
|
0.0003
|
0.0005
|
| Coefficient of time instability, %/y
|
(0.4-0.5) 10-3
|
(0.4-0.5) 10-3
|
(0.5-0.8) 10-3
|
Features: Single crystal permanent magnets keep their
properties at heavy conditions of service, specifically:
-
At vibrating loads at frequency from
5 to 10,000 Hz
-
Frequent impact loads of acceleration
to 500g
-
Environment temperature cycling from
"–" 60oC to "+" 250oC<
-
Humidity up to 98% at
temperature "+" 40oC
-
High mechanical strength of FeCoCrMo
alloys allow for using them as a structural material in
high mechanically loaded products (e.g. in high frequent
rotary machines)<
Fields of applications:
- Hysteresis brakes
- Micro motors and other electric machines
- Electronic devices
- Radio electronic devices
- Instrument making
- Seismo-sensors
- Precise instruments for aerospace and defense technologies
Processing. Single crystal blanks of
Alnico alloys (Alnico 9) and FeCoCrMo types are
manufactured by high productive method of controlled
directional crystallization. Alloy melting and directional crystallization
take place in inert atmosphere after preliminary evacuation.
Grown blanks are controlled, machined, and heat treated
in magnetic field.
