1. REPORTING PERIOD : 2nd QUARTER 2019
Laboratory of Inorganic Materials
PROGRESS REPORT ON FERRITE RESEARCH & DEVELOPMENT ACTIVITIES
REPORTING PERIOD : 2nd QUARTER 2019

2. RESEARCH ON MATERIALS AND PROCESSES: 3C95T-3C97T (AM) MATERIALS
General Target:
Continuation of the evaluation of ageing performance of 3C95/3C95T/3C97T pilot batches and evaluation of their specific resistivity before and after ageing.
Work performed/Results:
Pilot batch power losses are well within expectations and very comparable to laboratory values.
The 100kHz/200mT power loss stability of the pilot batches after 100 hour at 200oC is shown in the figure. The very good stability of 3C95T is attributed to the high concentration of titanium.

3. RESEARCH ON MATERIALS AND PROCESSES: 3C95T-3C97T (AM) MATERIALS
The effect of the sintering curve on the losses and thermal stability of 3C95T (pilot batch 3ARa) is shown on the figure.
The level of % change due to the thermal exposure is comparable in all cases.
The smallest impact due to the ageing test is identified in the case of the sintering trial that includes the plateau, indicating that a more solid distribution of the dopants is possibly achieved trough such a sintering cycle, in a way that this equilibrium is disturbed less under a thermal exposure process.
Average Specific Resistivity values before and after ageing
PB 3C95 exhibits the lowest DC specific resistivity due to the absence of Ti.
PB 3C95T exhibits the highest DC specific resistivity due to its very high Ti content.
A high ρ value is also obtained for PB 3C97+.
The ageing test (thermal exposure at 2000C/100h) significantly affects the specific resistivity of Ti-free 3C95 PB.
This implies that a re-distribution of dopants may be taking place (at grain boundaries, between tetrahedral/octahedral sites or other phenomena)

4. RESEARCH ON MATERIALS AND PROCESSES: 3C95T-3C97T (AM) MATERIALS
General Target:
Evaluation of Pilot batch 3C95T v2 3QIa (based on A3F3T20M30): electromagnetic performance, ageing performance
The decrease of titania in batch 3Qla increased both losses and ageing instability. The performance almost simulates no titania containing samples
Thermal exposure (at 2000C/100h) seems to improve the QF in batch 3Qla

5. RESEARCH ON MATERIALS AND PROCESSES: 3C95T-3C97T (AM) MATERIALS
General Target:
Starting the development of a new material that fulfills the specification provided by Tokai (Japan) of losses around 700 mW/cc at 200kHz, 200mT, 130oC.
Existing 3C95/3C97 material evaluation revealed that none fulfills the requirements. More evaluations on other grades for these conditions will be made and a design plan will be formed towards the development of a material that fulfills the very challenging power loss specifications. To the current knowledge there is no such material in the market today.

6. RESEARCH ON MATERIALS AND PROCESSES: 3C95T-3C97T (AM) MATERIALS
General Target:
The development of a flat high temperature Pv material without thermal ageing and better high temperature Pv than 3C95T on products
For that the myi/Pv stability down to -40*C must be abandoned; minimum requirement is myi > 1000 at -40*C, as requested by Valeo
Work performed/Results:
The work has been continued to complete the compositional matrix design some quarters earlier by synthesizing and evaluating the samples in light blue
Based on lab combinations on Co/Ti and Mn/Zn the best candidate is: A4F4T40M34 with 10% ageing
No pilot batch production at this moment, waiting for market demand and Pv200/200/130 project results

7. RESEARCH ON MATERIALS AND PROCESSES: 3C95T-3C97T (AM) MATERIALS
General Target:
Create fundamental understanding on the ageing instabilities shown by Cobalt containing grades through scientific cooperations with other European Institutions
In the Figure the anisotropy constant as a function of temperature is shown for two identical Cobalt containing grades with different additional titanium content. As can be seen the reason for ageing is the increase of the anisotropy constant (presumably due to reorientation of the highly anisotropic cobalt ions). In the presence of titanium this reorientation does not take place which explains the good ageing stability as long as titanium is added to counteract the effects of Cobalt
SEM investigations of the same samples indicated a clearly different behavior during etching which has not been explained yet. One hypothesis is that during the ageing process some ion migration/diffusion might take place which is hindered in the presence of titanium

8. RESEARCH ON MATERIALS AND PROCESSES: DENSIFICATION OF LARGE PRODUCTS
General Target:
Within this project entity the addition of vanadium oxide on the densification, specific resistivity and magnetic performance of 3C92 has been evaluated.

9. RESEARCH ON MATERIALS AND PROCESSES: 3F36 THERMAL AGEING
General Target:
Within this project entity the effect of vanadium as an alternative for titanium has been evaluated concerning the thermal stability of 3F36 cores.
Work performed/Results:
thermal ageing only for 100h, at 100, 125, 150, 175, 200oC
Comparison with previous results of 3F36 containing Titania
 shifts Pv min to the left, to lower temperatures
counter clockwise rotation of Pv-T curve
losses min moved to lower level
increase of ui , rotation of u-T curve which finally leads to a very flat u-T curve (for S40)

10. RESEARCH ON MATERIALS AND PROCESSES: 3F36 THERMAL AGEING
The effect of thermal ageing is clear and serious for high temperatures.
Higher effect as the temperature is increasing.
For 100 and 125°C the effect is very limited/minimal,
while for 175 and 200°C it is much bigger resulting to very low losses.

11. RESEARCH ON MATERIALS AND PROCESSES: 3F46+
General Target:
Within this project entity the effect Silica additions has been evaluated and compared with Vanadia additions reported in earlier quarterly reports.
reference
S powders with SiO2, as VN powders with V2O5,
give low losses especially at high frequencies
and not at low frequencies, compared to 3F46
SiO2 experimental group (S powders) give lower
losses than V2O5 experiments (VN powders)
3F46A 11Pa gives the lowest losses, although
S25 is now very close to 11Pa, especially
at high frequencies >3 MHz
After the experiments made during Q2 in lim,
S25 with 2500 ppm SiO2 sintered at 1100°C
gives the lowest losses
500 ppm V2O5
500 ppm V2O5
PB reference
350 ppm SiO2
250 ppm SiO2

12. TECHNICAL SUPPORT ON FACTORY PROJECTS-PRODUCT STICKING
Dilatometric investigations on several industrial flakes in order to evaluate their degree of expansion (an potential product sticking) upon sintering,, under various atmospheres.

13. TECHNICAL SUPPORT ON FACTORY PROJECTS-TITANIA
High Temperature X-Ray diffraction to determine the structure of Titania dopant and correlated it with the observed differences in the densification of certain grades.
TiO2 Chilisin, 25oC, Anatase
Rutile
1300oC,
TiO2 TiONa, 25oC, Rutile
TiO2 Sigma, 25oC, Anatase

14. TECHNICAL SUPPORT ON FACTORY PROJECTS-3C96
SEM Investigations on 3C96 factory lab samples incorporating titania from a new supplier

15. TECHNICAL SUPPORT ON FACTORY PROJECTS-4A15
SEM Investigations on the surface and interior of 4A15 products
Surface
Interior

16. TECHNICAL SUPPORT ON FACTORY PROJECTS-COMPETITOR F395-SUMIDA
SEM Investigations on Competitor’s sample (F395, Sumida)

17. TECHNICAL SUPPORT ON FACTORY PROJECTS-3C95
SEM Investigations on factory’s lab and production 3C95 samples
3C95 LAB1
3C95 LAB2
3C95 PRODUCTION

18. TECHNICAL SUPPORT ON FACTORY PROJECTS-COMPETITOR, APC
SEM and X-Ray Investigations on APC alloyed powder cores
SENDUST S225138A
GDR AR
SENDUST S225138A
SENDUST S244192A
GDR AR
SENDUST S244192A
ULTRAFLUX U225138A
ULTRAFLUX U225138A