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Lithium-ion Batteries and Hydrogen Fuel Autonomous Driving

Evaluation of Compositional Distributions in Neodymium Magnets Used Evaluation of Sensor Materials for Autonomous Driving
in Electric Motors – Ensuring Sensor Sensitivity Performance –

– High-Sensitivity High-Spatial Resolution Mapping by FE-EPMA –
Of the daily advancements in developing more environmentally friendly and fuel-efficient automotive magnetic motors, neodymium magnets have There has been a dramatic increase in automotive optical parts. Examples include head-up displays, cruise control cameras, and collision prevention
been primary contributors in the development of smaller and more energy-efficient products, due to their powerful magnetic field. Because the sensors for avoiding accidents. One thing common to all such parts is the importance of how dependent transmittance and reflectance are on the
properties of neodymium magnets vary depending on heat, dysprosium is added to improve heat resistance, but because dysprosium is one of the angle. Most of the parts were originally developed for smartphone applications, but more reliable data is required.
most expensive and rare rare-earth metals, magnets are being developed that minimize the quantities used. Due to the increasing requirements for
magnets made of even smaller crystal grains, more and more customers are requesting instruments that offer both high-sensitivity and high-spatial Evaluation of Optical Properties that Depend on Angle
resolution. The following describes an FE-EPMA system that satisfies both of those requirements.
Are optical properties the same even if the incident angle changes?

Example that requires transmittance: Collision prevention sensor Example that requires reflectance: Head-up display

Field of view where performance
must be ensured
Field of view where
performance must Collision pr evention sensor
Collision prevention sensor
be ensured

Sensor cover
Sensor cover
Head-up display

Is sensitivity the same at the outer edges of the viewing How does visibility vary depending on driver height?
angle as at the center?
COMPO 10.0 kV ×6000 Nd La 10.0 kV ×6000
5 µm 5 µm

The figures above show the results from imaging the composition distribution and element distribution in a neodymium magnet. In addition to smaller Using a variable angle measurement attachment, performance can be confirmed at a variety of angles.
crystal grains that constitute magnets, the manufacturing process was optimized to surround the crystal grains with a thin uniform boundary layer
(neodymium phase). That is expected to increase retention forces as an indicator of heat resistance, and reducing the dysprosium content is expected Overview of Variable Angle Measurement Attachment Example of Cover Material Measurement Results
to save resources and reduce manufacturing costs.
100
Transmittance at 35-degree
angle of incidence
80 Transmittance at 45-degree
Sample
Electron Probe Microanalyzer stage Polarizer angle of incidence
Transmittance at 55-degree
EPMA-8050G Transmittance (%) 60 angle of incidence
EPMA-8050G 40
20
UV-2600 + MPC-2600A
Min. Resolution 3 nm Detector 0
900 940 980 1020
Wavelength (nm)
20 nm （10 nA ・ 10 kV） When the viewing angle reaches 55 degrees, the level of 980
The sample and detector can be freely rotated to nm light decreases by half.
Resolution in Analytical 50 nm （100 nA ・ 10 kV） measure absolute reflectance and transmittance. → To maintain sensitivity, the viewing angle must be restricted
Conditions 150 nm （1 µA ・ 10 kV） or the measurement wavelength must be changed.
Max. Irradiation Current 3 µA Spectrophotometer UV-2600 UV-3600 Plus SolidSpec-3700

Note: The indicated resolution value is the secondary electron Wavelength Region 250-1400 nm 250-1650 nm 250-2500 nm
resolution given the specified conditions.
Reflectance Measurement Incident angles from 5 to 70 degrees and input angles from 10 to 140 degrees
Transmittance Measurement Input angles from 0 to 90 degrees
Sample Sizes 25 × 25 to 70 × 70 mm, up to 15 mm thick

· 150 nm resolution achieved at 10 kV and 1 µA · Reflectance can be measured from incident angles of 5 degrees.
· High current irradiation possible even at up to 3 µA · Both reflectance and transmittance can be measured without changing the sample position.
· Compatible with bumpy or curved samples, it can be used for a wide variety of applications and samples. · Optical properties within the sunlight range (250 to 2500 nm) can be confirmed (using the SolidSpec-3700 spectrophotometer).

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