JPS6359242B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a ferrite magnetic core used in a high temperature range (for example, 150°C or higher), and a specific example of the purpose is a ferrite core with low power loss used for a light source of a fluorescent discharge lamp. This is related to.

Furthermore, the present invention is used in high-magnetic metals with a magnetic flux density of 500 Gauss or more, and reduces power loss in high temperature ranges (e.g., 150°C or higher), which have not been a problem with conventional oxide magnetic materials. The objective is to create a so-called ferrite with low power loss and high stability for high temperature ranges, which has been improved and has also improved the magnetic instability that occurs in high temperature ranges.

Typical properties required of conventional oxide magnetic materials (hereinafter referred to as ferrite) can be summarized in the following three points.

That is, (1) High magnetic permeability (2) Low loss (3) High magnetic stability.

The main focus of improvement on conventional ferrite has been to improve the above three properties in the target frequency band of the material.

However, no matter how wide the temperature range in which conventional ferrite is put into practical use, it never exceeds the range of -30°C to 100°C. Also, among the three items above
(3) That is, magnetic stability is called the accommodation of instability, and has been the subject of many studies.

Regarding the relationship between temperature and accommodation, for example, Krupicka et al.
We investigated disaccommodation in a wide temperature range up to around 400℃, and found that disaccommodation appeared at various temperatures and decreased to 0 when the amount of oxygen was reduced.
It has been reported that the peak that appears near °C is not shifted in position but becomes significantly lower.

However, research on improving magnetic instability has been conducted mainly at room temperature within the above-mentioned practical temperature range of conventional ferrite (-30°C to 100°C).

Since the object of the present invention is a high temperature range (150°C or higher), which has not been a problem in the past, and
In the case of ferrite used for a fluorescent discharge lamp light source, which is a specific application of the present invention, the ferrite is sealed in a discharge lamp,
Because it is exposed to high temperatures of more than 200℃ due to high magnetic flux density conditions of more than 500 Gauss and plasma discharge,
It is necessary to improve changes over time at temperatures above ℃.

The present invention provides a low power loss, high stability ferrite magnetic core for high temperature ranges that improves magnetic instability that appears in high temperature ranges (200°C to 300°C). That is, the present invention is a ferrite magnetic core that is driven at high temperatures in a magnetic field of 500 G or more, and which contains 13 to 33 mol% of manganese oxide (MnO), 6 to 20 mol% of zinc oxide (ZnO), and nickel oxide (NiO). , magnesium oxide (MgO), lithium oxide (LiO)
It has a basic composition consisting of 9 to 25 mol% of at least one of these and 45 to 52 mol% of iron sesquioxide (Fe ₂ O ₃ ), and the temperature at which the power loss Pc in a 700G magnetic field shows a minimum value is 150 ℃ or higher, [Pc after 100 hours - Pc after 1 hour] x 100 / [Pc after 1 hour]
The present invention relates to a ferrite magnetic core characterized in that the rate of change over time of Pc expressed by is 30% or less, and the details of the present invention will be described below. That is,
Depending on the required use, Ni-Mn-Zn system or
A method for manufacturing ferrite having low power loss in an arbitrary high temperature range (150°C to 300°C) by carefully selecting the basic composition ratio of Mn-Mg-Zn system and Li-Mn-Zn system will be described below.

Figure 2 shows Ni-Mn-Zn ferrite.
When iron sesquioxide (Fe ₂ O ₃ ) is kept constant at 54 mol %, the total of the other three components is 46 mol %. Namely, manganese oxide (MnO), zinc oxide (ZnO),
The relationship between nickel oxide (NiO) and the temperature at which the power loss Pc is minimal (hereinafter referred to as Tpcmin for simplicity) is shown. In FIG. 2, Tpcmin moves in the direction of arrow T.

Note that this figure 2 is for measurement conditions of 100 kilohertz and 700 gauss. All measurement conditions below are 100
This shows what was done at 700 Gauss in kilohertz.
As shown in FIG. 2, there is a clear relationship between Tpcmin and the composition, and in the present invention, this relationship was investigated in detail over the entire practical composition range. As a result, even when the amount of iron sesquioxide (Fe ₂ O ₃ ) was varied, as the amount increased or decreased,
If we reduce and increase nickel oxide (NiO), that is,
If Fe ₂ O ₃ + NiO = constant, the Kyrie point does not change, but is inversely proportional to the amount of iron sesquioxide (Fe ₂ O ₃ ).
It was discovered that although Tpcmin moves to the lower temperature side, there is no change in the tendency for other component compositions. An example of this is shown in FIGS. 3 and 4.

Figure 3 shows the relationship between other three components, namely manganese oxide (MnO), zinc oxide (ZnO), nickel oxide (NiO), and Tpcmin when 52 mol% of iron sesquioxide (Fe ₂ O ₃ ) is constant. Show relationships. Figure 4 shows
Similarly, it is a diagram when 56 mol% of iron sesquioxide (Fe ₂ O ₃ ) is constant. Comparison of Figures 2, 3, and 4 reveals that, as mentioned above, Tpcmin shifts to the lower temperature side in inverse proportion to the amount of iron sesquioxide (Fe ₂ O ₃ ), but there is no change in the tendency for other component compositions. This shows that it cannot be seen.

It was also observed that this relationship did not change at all even when nickel oxide (NiO) was replaced with magnesium oxide (MgO) or lithium oxide (LiO).

However, in the case of magnesium oxide (MgO), when replacing the same mole as nickel oxide (NiO), Tpcmin is lower than that of nickel oxide (NiO).
was observed to move approximately 40°C lower in parallel. Figure 5 shows the situation.

Furthermore, when replacing with lithium oxide, Tpcmin was observed to move in parallel to a temperature approximately 10°C higher than in the case of nickel oxide. Figure 6 shows the situation.

However, it was also observed that the temperature characteristics of power loss showed the same tendency in both cases.

FIG. 7 shows an example of the temperature characteristics of power loss when the component system is changed.

When replaced with magnesium oxide (MgO),
Compared to nickel oxide (NiO), the Kyrie point is 15℃
When the temperature was lowered and replaced with lithium oxide (LiO), the Curie point increased by 5°C, and this tendency was also observed to shift in parallel over a wide range of compositions.

Therefore, the following examples will be representative of the Ni-Mn-Zn system, and the details will be explained.

As a specific example, if Tpcmin is around 240℃ (actual operating temperature range 180℃~300℃) and Tpcmin is
Consider the case of manufacturing a material that meets two types of material requirements around 290°C (actual operating temperature range of about 230°C to 350°C) and minimizes power loss Pc in the specified temperature range.

Tpcmin is 240℃ requirement is D, Tpcmin290
Let E be the requirement for °C. From the relationship in Figure 2, D is
It is obvious that E should be selected on the Tpcmin=240°C line and E should be selected on the Tpcmin=290°C line. The line of each line and the iron sesquioxide composition are determined based on the conditions such as the frequency band used for the required material and the economic efficiency.The higher the frequency band, the higher the nickel oxide ratio. be selected.

Tpcmin based on the required frequency band and economical conditions
Assume that both points D and E are selected on the line according to FIG.

That is, D is 54 mol% of iron sesquioxide (Fe ₂ O ₃ ), 25 mol% of manganese oxide (MnO), 10 mol% of nickel oxide (NiO), 11 mol% of zinc oxide (ZnO),
Similarly, E is 54 mol% of iron sesquioxide (Fe ₂ O ₃ ), 33 mol% of manganese oxide (MnO), 12 mol% of nickel oxide (NiO), 1 mol% of zinc oxide (ZnO),
It is.

The raw material compounds calculated and weighed to have the compositions D and E above are thoroughly mixed in a ball mill or similar mixer, calcined in air at 900°C for 3 hours, and then subjected to a ball mill or similar pulverization operation. Thoroughly pulverize by placing.

At this time, an appropriate amount of additives are added to improve loss. Through the above steps, the Ni-Mn-Zn ferrites D and E are kneaded with a binder, and after molding, the temperature is 1350℃.
Figure 8 shows the temperature characteristics of the power loss Pc at 100 kHz and 700 Gauss for a sample obtained by firing in nitrogen gas containing 2% oxygen for 3 hours.

Total power loss in the target temperature range as shown in Figure 8
It is clear that Pc shows a minimum value and Tpcmin shifts. As described above, the present invention shows that power loss is improved in a severe high temperature range that was unimaginable with conventional oxide magnetic materials.

Figure 9 shows manganese oxide (MnO) 23 mol%,
Electric power of samples manufactured in the same manner as in the previous example, with zinc oxide (ZnO) kept constant at 10 mol% and the ratio of iron sesquioxide (Fe ₂ O ₃ ) and nickel oxide (NiO) varied. Shows the temperature characteristics of loss Pc. Furthermore, the ninth
The numerical values in the figure indicate mol% of Fe ₂ O ₃ . As described above, FIG. 9 shows that as the amount of iron sesquioxide increases (the amount of nickel oxide decreases), the power loss, especially in the low temperature region, becomes better.

FIG. 9 also shows iron sesquioxide (Fe ₂ O ₃ ), a ferrite material for a fluorescent discharge lamp light source, which is a specific application of the present invention.
This indicates the lower limit of the composition. In other words, in this application, the permissible limit for power loss near room temperature is approximately 1000 milliwatts/cm ³ , so iron sesquioxide (Fe ₂ O ₃ ) is required to be at least 45 mol % for this application. This shows that.

On the other hand, Fig. 10 shows the change in power loss over time for this sample at a temperature of 220°C or higher. The vertical axis shows the rate of change in power loss after 1HR to 100HR. It is clear that as the iron sesquioxide (Fe ₂ O ₃ ) ratio increases, the change over time increases, and the temperature at which the rate of change peaks shifts to lower temperatures.

The relationship between the temperature characteristics of power loss and the magnitude of its change over time (i.e., magnetic instability) in Figures 9 and 10 above has an antinomic relationship, and inevitably a compromise between the two is necessary. It is clear that we must find out. Therefore, the standard is that the rate of change over time is 30% or less at 220°C to 300°C.

This means that iron sesquioxide (Fe ₂ O ₃ )
It is clear from Fig. 10 that the content should be 52 mol% or less. In other words, from Fig. 9 mentioned above, the iron sesquioxide (Fe ₂ O ₃ ) composition is 45 It is clear that it must be in the range of mol % or more and 52 mol % or less from the guideline of the magnitude of change over time as shown in Figure 10.

On the other hand, since the material components of the present invention are quaternary, unlike the previous example where manganese oxide (MnO) and zinc oxide (ZnO) were constant, iron sesquioxide (Fe ₂ O ₃ ) and nickel oxide (NiO) components were used. Figures 11 and 12 show cases in which the manganese oxide (MnO) and zinc oxide (ZnO) ratios are varied while keeping the ratio constant.

Figure 11 shows the power loss of a sample manufactured using the same method as the previous example, with iron sesquioxide (Fe ₂ O ₃ ) at 52 mol% and nickel oxide (NiO) at 15 mol%.
Shows the temperature characteristics of PC. The numbers in Figure 10 are
Shows the mol% of ZnO. As shown in FIG. 10, as zinc oxide decreases (manganese oxide increases), the power loss becomes better, the Curie point increases to a higher temperature, and Tpcmin also shifts to a higher temperature.

Similarly to FIG. 9, FIG. 11 also shows the upper limit of the composition of zinc oxide (ZnO) in the ferrite material for a fluorescent discharge lamp light source, which is a specific application of the present invention.
Moreover, the reason for the Curie point of the present invention is also shown at the same time.

That is, according to Figure 11, when zinc oxide (ZnO) exceeds 20 mol%, it exceeds 1000 mw/ ^cm3 , and when zinc oxide (ZnO) is 22 mol%, not only does the Curie point decrease to 265°C, but also It also shows that power loss rapidly deteriorates near the point.

Figure 12 shows the change in power loss over time for this sample at temperatures above 220°C.

The vertical axis shows the rate of change in power loss after 1HR to 100HR. It is clear that when the zinc oxide (ZnO) ratio is decreased, the rate of change over time increases, and the temperature at which the rate of change peaks shifts toward lower temperatures.

Similar to when iron sesquioxide (Fe ₂ O ₃ ) is varied, when zinc oxide (ZnO) is varied, the temperature characteristics of power loss and The relationship between the magnitude of change over time (that is, magnetic instability) has an antinomic relationship, and a compromise must necessarily be found between the two. Therefore, as in the case of iron sesquioxide (Fe ₂ O ₃ ), the standard is that the rate of change over time is 30% or less at 220°C to 300°C.

From FIG. 12, it is clear that the content of zinc oxide (ZnO) should be 6 mol% or more. As mentioned above, as in the case of iron sesquioxide (Fe ₂ O ₃ ), the composition range of zinc oxide (ZnO) is 6 from Figures 11 and 12.
It is also clear that the content should be from mol% or more to 20 mol% or less.

As mentioned above, the regulatory conditions for the composition of two components of the quaternary system are iron sesquioxide (Fe ₂ O ₃ ) 45 mol% or more;
52 mol% or less, zinc oxide (ZnO) 6 mol% or more,
As a result of a detailed investigation with the composition range limited to 20 mol % or less, a sample representative of the present invention shown below was obtained.

Its characteristics are shown in FIGS. 13 and 14.

That is, FIG. 13 shows a temperature characteristic diagram of power loss of a representative example sample.

FIG. 14 shows the change in power loss over time for ¹⁰⁴ hours between 200°C and 300°C (200°C, 250°C, 270°C, and 300°C) for a representative sample.

As shown in FIG. 14, this sample showed no change in power loss over time during 10 ⁴ HR between 200°C and 300°C.

As mentioned above, the effects obtained by the present invention are that of manganese oxide (MnO). 13 to 33 mol%, 6 to 20 mol% of zinc oxide (ZnO), 9 to 25 mol% of at least one of nickel oxide (NiO), magnesium oxide (MgO), and lithium oxide (LiO), iron sesquioxide (Fe _2O3 ) has a basic composition of 45 to 52 mol%, and the temperature at which the power loss Pc in a 700G magnetic field shows a minimum value is 150℃ or higher, [ _Pc after 100 hours - Pc after 1 hour] Pc】×100/
The rate of change in Pc over time expressed as [Pc after 1 hour] is
A ferrite magnetic core with a concentration of 30% or less can be obtained. That is, if the material of this representative example sample is used as a ferrite magnetic core for a fluorescent discharge lamp and a light source, which are specific examples of the present invention, it can be sealed in a discharge lamp and generate plasma under high magnetic flux density conditions of 500 Gauss or more. due to discharge
Even if the device is left at high temperatures of over 200°C for long periods of time, it is possible to create an extremely stable design without causing any change in power loss over time. This makes it possible to dramatically improve the lifespan of the light source as a fluorescent discharge lamp, and is a great invention that will contribute to the electronic materials industry.

[Brief explanation of drawings]

FIG. 1 is a characteristic diagram showing the relationship between temperature and day accommodation reported by Krupicka. Figure 2 54 mol% of iron sesquioxide (Fe ₂ O ₃ ) from the present invention
This figure shows the relationship between the composition of Ni-Mn-Zn ferrite and the temperature Tpcmin at which the power loss reaches a minimum value under a constant condition. Figure 3 shows Ni−Mn− when iron sesquioxide (Fe ₂ O ₃ ) is kept constant at 52 mol%.
This figure shows the relationship between the composition of Zn-based ferrite and the temperature Tpcmin that indicates the minimum value of power loss. Fourth
The figure shows the relationship between the composition of Ni-Mn-Zn ferrite and the temperature Tpcmin that indicates the minimum value of power loss when iron sesquioxide (Fe ₂ O ₃ ) is kept constant at 56 mol %. Figures 5 and 6 show iron sesquioxide (Fe ₂ O ₃ )
Nickel oxide (NiO) at a constant 54 mol%
Magnesium oxide (MgO), respectively, as a replacement for
Mn−Mg− when using lithium oxide (LiO)
It shows the relationship between the composition of Zn-based ferrite and Li-Mn-Zn-based ferrite and the temperature Tpcmin that indicates the minimum value of power loss. In comparison with FIG. 2, it shows that Tpcmin deviates when the composition system changes. FIG. 7 shows a typical example of the temperature characteristics of power loss when the component system is changed. Even if the component system changes, the tendency of the characteristics does not change at all, and Tpcmin
This shows that the Kyurie point shifts. FIG. 8 shows the temperature characteristics of power loss in the case of Ni--Mn--Zn ferrite according to the present invention, in which materials with different service temperature ranges are obtained. Figure 9 shows manganese oxide (MnO) and zinc oxide (ZnO) each containing 23 mol% and 10
Ni−Mn− with a constant mol% and varying the ratio of iron sesquioxide (Fe ₂ O ₃ ) and nickel oxide (NiO).
The temperature characteristics of power loss of Zn-based ferrite are shown.
Figure 10 shows the power loss of the sample in Figure 9 from 220°C.
Shows the aging characteristics at 300℃. Figure 11 shows
Iron sesquioxide (Fe ₂ O ₃ ) and nickel oxide (NiO) were kept constant at 52 mol% and 15 mol%, respectively, and the ratio of manganese oxide (MnO) and zinc oxide (ZnO) was varied.
The temperature characteristics of power loss of Ni-Mn-Zn ferrite are shown. FIG. 12 shows the temporal change characteristics of the power loss of the sample shown in FIG. 11 at 220° C. to 300° C. Figure 13 shows the results obtained in the present invention at temperatures above 200°C.
No deterioration occurs over a long period of time in the high temperature range of 300℃.
That is, the temperature characteristics of the power loss of a typical example material of high temperature range low power loss high stability ferrite is shown. FIG. 14 shows the results of long-term observation of the change in power loss over time of ¹⁰⁴ hours at 200° C. to 300° C. for the representative example material shown in FIG. 13.

Claims (1)

[Scope of Claims] 1. A ferrite magnetic core driven at high temperatures in a magnetic field of 500 G or higher, comprising 13 to 33 mol% of manganese oxide (MnO), 6 to 20 mol% of zinc oxide (ZnO), and nickel oxide ( NiO),
9 to 25 mol% of at least one of magnesium oxide (MgO) and lithium oxide (LiO),
It has a basic composition consisting of 45 to 52 mol% of iron sesquioxide (Fe ₂ O ₃ ), and the temperature at which the power loss Pc in a 700G magnetic field shows a minimum value is 150°C or higher, and [Pc after 100 hours] - Pc after 1 hour] x 100/[Pc after 1 hour] A ferrite magnetic core characterized in that the rate of change over time of Pc is 30% or less.