JPH04116145A - Heat sensitive amorphous alloy coated with metal - Google Patents

Abstract

PURPOSE:To produce the heat sensitive amorphous alloy which can make induction heating to a prescribed temp. range at all times by coating the surface of an alloy contg. transition metals, such as Fe, Ni and Co and semimetals, such as P, C, Si, and B, and having a specific Curie temp. with a nonmagnetic metal. CONSTITUTION:The heat sensitive amorphous alloy for thermotherapy is produced by coating the surface of the alloy contg. one or >=2 kinds of the heat sensitive amorphous alloys, such as Fe, Ni and Co and one or, >=2 kinds of the semimetals, such as P, C, Si, and B, and having 42 to 90 deg.C Curie temp. with the nonmagnetic metal (metals, such as Cu, Ag and Au, having a good electric conductivity). The content of the above-mentioned semimetals is confined to about 10 to 30 atomic % in the alloy and the thickness of the film of the nonmagnetic metal is preferably about 5 to 10mum. The heat sensitive amorphous alloy which inductively heats an affected part to a prescribed temp. at all times is obtd. in this way without requiring special control and the stable thermotherapy is executed.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a magnetic material for biological heating, and more specifically, for use as an implant material for local heating in hyperthermia, which is a type of treatment for malignant tumors such as cancer. Regarding possible planetary amorphous alloys.

[Conventional technology]

A method of cancer treatment that focuses on the difference in heat sensitivity that exists between malignant tumor cells such as cancer and normal cells, and heats the temperature near the tumor to 42 degrees Celsius or higher (
Hyperthermia) began to be researched around 1960,
With recent remarkable advances in heating technology, a wide range of applications are being attempted. Hyperthermia is broadly classified into whole body thermotherapy and local thermotherapy depending on the heating method used.

Whole body thermotherapy uses warm water and melted paraffin.
In Japan, extracorporeal circulation blood warming is the most popular method.

Local heat therapy often uses electromagnetic waves, such as microwave heating (2,450MHz, 915MHz, 43
4MHz, etc.), RF induction heating (27, 12MHz, 1
3.56MHz), RF dielectric heating (13,56MHz
, 8 MHz) and ultrasonic heating (1-3 MHz) have been approved for manufacturing by the Ministry of Health and Welfare and are in clinical application. In particular, RF dielectric heating devices are the mainstream for Japanese people who have little subcutaneous fat.

In principle, microwave heating can only be heated to a depth of several centimeters from the epidermis, and is effective only for superficial tumors. In RF dielectric heating, the area around the electrode and subcutaneous fat are selectively heated, making it difficult to heat only the affected area. Also, RF
Although induction heating allows deep heating, it has the disadvantage that the heat generation pattern is likely to be disrupted due to nonuniform impedance within the body, and areas other than the lesion are also heated. Furthermore, heating by ultrasonic waves has good convergence and is suitable for deep local heating, but there are limits to the areas where it can be applied because it is reflected at the interface with bones and air.

Although all of the methods described above have the advantage of being non-invasive in terms of heating, it is not easy to reliably achieve local heating deep within the body.

Therefore, high temperature areas in unnecessary places (Hot 5pot)
In order to prevent such occurrences, it is necessary to constantly measure the temperature, which results in an invasive method. Furthermore, it is difficult to predict the location where Hot SρOt occurs, and an appropriate temperature distribution measurement method has not yet been established. In general, when using electromagnetic waves, the essential point is that if the frequency is increased, local heating is possible but deep heating is difficult, and if the frequency is lowered, deep heating is easier but the heating range is wider. I have a problem.

A method called the soft heating method has been developed in recent years to overcome these problems with electromagnetic wave-applied hyperthermia. In this method, a temperature-sensitive magnetic material is implanted into a tumor in a living body, and hysteresis loss generated by excitation with a high-frequency alternating magnetic field is used as a heat source.

All of the temperature-sensitive magnetic materials (ferrite, NiSi, Fe, C, etc.) that have been considered as implant materials for this soft heating method have poor heating efficiency near room temperature. Moreover, it is not easy to maintain a stable temperature required for treatment. In order to improve these practical characteristics,
Composite heating elements made of a combination of magnetic and non-magnetic materials have been devised, but there are many instability factors, and characteristics that would lead to practical use have not yet been achieved.

Recently, it has been proposed to use amorphous alloy powder as a hyperthermia implant material (rB
iomedical thermography”,
Voj! .

7, Nα1.7-10, 1987). This implant material is embedded in an agar phantom, inserted into a cancerous area deep within a living body, and heated by induction using a high-frequency magnetic field.

[Problem to be solved by the invention]

However, since the amorphous alloy used in this implant material has a high Curie temperature of several hundred degrees Celsius, when an external alternating magnetic field is applied, the temperature will exceed approximately 45 degrees Celsius (too high). In order to set the temperature, it is necessary to control the external magnetic field and adjust the temperature.However, the heating state differs depending on the location and condition of the affected area, and it is necessary to adjust the temperature while accurately detecting the temperature of the affected area. Therefore, there is a problem that heating therapy becomes complicated.

Therefore, an object of the present invention is to provide a temperature-sensitive amorphous alloy surface-coated with a non-magnetic metal for use as an implant material, which can constantly induce the affected area to a predetermined temperature range without requiring special control. be.

[Means to solve the problem]

As a result of intensive research in view of the above objectives, the present inventors have found that by increasing the amount of Ni in the composition system of an amorphous alloy, the Curie temperature can be lowered to a desired level.
It has been discovered that the heating temperature of an amorphous alloy can be constantly maintained at a desired level of about 42 to 45°C without controlling an external alternating magnetic field during induction heating, and this has been reported in Japanese Patent Application Laid-Open No. 2-52663 and The present invention was completed by further improving the magnetic materials disclosed in JP-A No. 2-47/243.

That is, the temperature-sensitive amorphous alloy for thermotherapy of the present invention comprises one or more transition metals of FC, Ni, and Co, and one or more semimetals of p, C, Si, and B. It has a Curie temperature of 42°C to 90°C, and is characterized in that the surface of the temperature-sensitive amorphous alloy is coated with a non-magnetic metal.

Broadly speaking, the present invention shows that when the Curie point is lowered to a desired level by adding Cr and/or MO to the composition system of an amorphous alloy, the amorphous alloy can be formed without controlling an external alternating magnetic field during induction heating. heating temperature of 4
They discovered that it is possible to constantly maintain the desired level of about 2 to 45°C, and completed the present invention.

That is, the temperature-sensitive amorphous alloy for thermotherapy of the present invention comprises one or more transition metals of Fe, Ni, and Co, and one or more semimetals of P, C, Si, and B. , Cr and /Mo, has a Curie temperature of 42° C. to 90° C., and is characterized in that the surface of the temperature-sensitive amorphous alloy is coated with a non-magnetic metal.

The present invention will be described in detail below.

The basic composition of the amorphous alloy of the present invention is (Fe, Ni,
Co) (P, C, Si, B).

Ni is an element added for the purpose of lowering the Curie temperature, and at the same time imparts corrosion resistance. In particular, lowering the Curie temperature is important as a magnetic material for soft heating.
This enables local heating to the temperature for treating a tragic tumor and maintenance of the treatment temperature.

Furthermore, the above composition has eight! By adding , the Curie temperature can be further lowered.

Therefore, AI! , an amorphous alloy with a low Curie temperature can be obtained even if the amount of Ni added is suppressed. In general, increasing the zero loading amount of Ni tends to decrease the magnetic flux density of the amorphous alloy, but as mentioned above, ^2
By suppressing the amount of Ni added, an amorphous alloy with a low Curie temperature and a small decrease in magnetic flux density can be obtained.

The Curie temperature needs to be in the range of 42-90°C.

This is because if the temperature is 42°C or lower, the temperature cannot reach a temperature range effective for hyperthermia, and if it is 90'C or higher, the inductance reduction temperature exceeds 55°C, exceeding the therapeutic temperature range and resulting in overheating.

The preferred Curie temperature is 60-75°C. Nihahe for this purpose! It is about 40 to 50 atomic % in the added alloy, and to! It is about 55 to 65 atomic % in the additive-free alloy.

In the case of an alloy with 2 additions, the amount of Afi added is preferably 2 to 5 atomic %.

The content of one or more metalloids of P, C, Si, and B is about 10 to 30 atomic % in the alloy.

The nonmagnetic metal is preferably a metal with good electrical conductivity such as Cu, Ag, or Au. This is because it increases the skin effect in an alternating magnetic field and improves the temperature rise characteristics during heating by generating heat due to eddy current.

The thickness of the non-magnetic metal film is preferably equal to or less than the thickness of the temperature-sensitive amorphous alloy powder, and a film thickness of 5 μm to 10 μm is particularly preferred. If the film thickness is thin, the improvement in temperature rise characteristics during heating will be weak, and if the film thickness is thick, the actual filling rate of the amorphous alloy itself will decrease, and the constant temperature part of the heating curve (p
lateau) become unclear.

Such amorphous alloy powder is obtained by pulverizing ribbons or flakes produced by ordinary melt quenching methods (single roll method, double roll method, cavitation method, etc.), and then chemically or physically applied to the amorphous alloy powder. This method can be obtained by coating the surface of an amorphous alloy powder with a conductive metal.

[Function] Since the amorphous alloy of the present invention has a relatively low Curie temperature, the heating curve becomes flat near the heating treatment temperature, and the temperature does not rise even if it is further excited. This leveled temperature is slightly lower than the Curie temperature, and rather corresponds to a drop in inductance and a sharp drop in temperature in the case of coil excitation. Due to this property, the temperature of the amorphous alloy never rises above a certain temperature even without controlling external excitation, and stable heating treatment can be performed. In addition, the metal surface coating allows rapid heating to the treatment temperature, thereby shortening the treatment time.

Furthermore, the basic composition of the amorphous alloy of the present invention is (Fe
,,Ni,,Co)MIM2 (However, N3 is Cr and/or Mo, and M2 is P
It is one or more metalloids of 1C, Si, and B.

).

? I, Cr and/or Mo are elements added for the purpose of lowering the Curie temperature, and at the same time impart corrosion resistance. In particular, a reduction in the Curie temperature is important as a magnetic material for soft heating, and enables local heating to a malignant tumor treatment temperature and maintenance of the treatment temperature.

The Curie temperature needs to be in the range of 42-90°C.

This is because if the temperature is 42°C or lower, it cannot be heated to a temperature range effective for hyperthermia, and if it is 90°C or higher, the inductance reduction temperature exceeds 55°C, exceeding the therapeutic temperature range and causing overheating.

The preferred Curie temperature is 60-75°C. For this purpose, Ml is contained in the alloy in an amount of about 12 to 13 atomic percent.

The semimetal M2 is one or more of P, C, Si, and B and accounts for about 10 to 30 atomic % in the alloy.

The nonmagnetic metal is preferably a metal with good electrical conductivity such as Cu, Ag, or Au. This is because it increases the skin effect in an alternating magnetic field and improves the temperature rise characteristics during heating due to heat generation due to eddy current. The thickness of the film is preferably equal to or less than the thickness of the amorphous flakes, particularly 5 μm to 10 μm.
A coating thickness of m is preferred.

If the thickness is small, the improvement in temperature rise characteristics is weak, and if the thickness is large, the actual filling rate of the amorphous alloy itself decreases, and the constant temperature portion (plateaυ) of the heating curve becomes unclear.

The temperature-sensitive amorphous alloy of the present invention is preferably in powder form so that it can be molded into a desired shape as an implant material. As the particle size of the amorphous alloy powder becomes smaller, the heating curve becomes gentler, and it takes more time to heat the affected area to the desired temperature. However, the above %'I
By coating the surface of the Q-characteristic amorphous alloy powder with a nonmagnetic metal, the heating rate when an alternating magnetic field is applied can be significantly improved.

Such amorphous alloy powder is obtained by pulverizing ribbons or flakes produced by a normal melting and quenching method (single roll method, double roll method, cavitation method, etc.). It can be obtained by coating the surface of an amorphous alloy powder with a non-magnetic metal using a conventional method.

Since the amorphous alloy of the present invention has a relatively low Curie temperature, the heating curve becomes flat near the heating treatment temperature, and the temperature does not increase even if the alloy is further excited. This leveled temperature is slightly lower than the Curie temperature, and rather corresponds to the temperature at which the inductance rapidly decreases in the case of coil excitation. Due to this property, the temperature of the amorphous alloy never rises above a certain temperature even without controlling external excitation, and stable heating treatment can be performed. In addition, heating to the treatment temperature is quick and treatment time can be shortened.

The present invention will be explained in further detail by the following examples.

Actual picture LfLL FeB,:+N1bo,b Siq,,B12.4(
From a molten metal having a composition of
Amorphous flakes with a length of 63 to 1000 μm were produced by pulverization.

The Curie temperature of the obtained amorphous alloy powder is 65°C
1 The crystallization temperature was 520'C.

C, a non-magnetic metal, is added to this alloy powder using an electroless plating method.
Coated with u (copper). The thickness of the film was 5-8 μm.

This powder and a flat powder not coated with a non-magnetic metal were classified, respectively, to obtain samples with and without Cu coating in the following particle size (length) range.

Sample N.

Particle size (μm) 63-14 49-29 97-50 00-100 As shown in Fig. 1, inner diameter D 6 m + n, length L50
Each sample was filled in a +nm non-magnetic pipe 1, and a 50-turn excitation coil 2 was wound around the outer circumference of the vibrator 1.
2 at a frequency of 100KHz. C) An alternating magnetic field of KA/m was applied. FIG. 2 shows the temperature rise characteristics for each sample not coated with a non-magnetic metal, and FIG. 3 shows the temperature rise characteristics for each sample coated with a non-magnetic metal. From Figure 2,
It can be seen that as the particle size increases, the temperature increase rate becomes faster and the temperature control characteristics become more stable, reflecting the decrease in the demagnetizing field coefficient. The controlled temperature here is 63 to 68°C, which is almost the same as the Curie temperature. It can be seen from FIG. 3 that the time required to reach the treatment temperature is significantly shortened by coating with non-magnetic metal.

Next, FIG. 4 shows the inductance at each temperature for each grain size, and it can be seen that the inductance decrease, that is, the impedance decrease occurs by 40 to 45 degrees Celsius.

From this, it can be seen that the temperature increase control characteristic of the sample of the example is approximately the Curie temperature, and is greatly influenced by the temperature change of the inductance.

Next 1 sentence Fe7 to NNi, 5ino Blz (alloy A),
I'e8tl-X N;, Pro Ill+o (alloy B) and FC! 75-X Nix PI3 B6 A
An amorphous alloy powder having the composition (atomic %) of I23 (alloy C) was prepared in the same manner as in Example 1! ! Built. The particle size of the powder was 63-100077 m. FIG. 5 shows the results of measuring the Curie temperature Tc for samples with various Ni contents.

It can be seen from FIG. 5 that the Curie temperature Tc of the alloy decreases as the Ni content increases. Tc is 42-9
In order to be within the range of 0°C, the Ni content in each system must be 59.0°C in the case of the Fe-Ni-5i-B system (alloy Δ).
In the case of Fc-N1-P-B system (alloy B), it is 60.8 to 63.9 at%, and Fe-
For N1-P-B-Ar system (alloy C) 44.3 to 49
．． It is 4 atom%. That is, by adding 3 atomic % of i, the amount of Ni added can be reduced by 15 to 20 atomic %. This makes it possible to suppress a decrease in the saturation magnetic flux density of the amorphous alloy.

The present invention will be explained in further detail by the following examples.

Real J1 Special 1 Febb, a Cr+3. ZP13.2C6,8(
From a molten metal having a composition of
Amorphous flakes with a length of 63 to 1000 μm were produced by pulverization to produce flat powder with a length of 63 to 1000 μm. The Curie temperature of the obtained amorphous alloy powder is 44℃1
Crystallization temperature is 470℃ 1 Saturation magnetic flux density Bs is 4200G
Met. A Cu film was formed by electroless plating. The thickness of the film was 5-8 μm.

This powder and powder not coated with non-magnetic metal are classified, and C
Samples with and without U coating were obtained in the following particle size ranges.

Sample No. Particle size (μm) 1 63-149 2 149-297 3 297-500 4 500-1000 As shown in Fig. 1, each sample was filled into a non-magnetic pipe 1 with an inner diameter D6 mm and a length L50 mm. A 50-turn excitation coil 2 is wound around the outer circumference of the pipe l, and a frequency of 1 is set.
2 at 00KHz. An alternating magnetic field of OKA/m was applied. Figure 6 shows the heating characteristics of each sample not coated with a non-magnetic metal, and Figure 7 shows the temperature rise characteristics of each sample coated with a non-magnetic metal. It can be seen that as the value increases, the temperature increase rate becomes faster and the temperature control characteristics become more stable, reflecting the decrease in the demagnetizing field coefficient.

It can be seen from FIG. 7 that the time required to reach the treatment temperature is significantly shortened by coating with non-magnetic metal.

Next, FIG. 8 shows the inductance at each temperature for each particle size, and it can be seen that a sudden decrease in inductance, that is, a decrease in impedance occurs at 40 to 45 degrees Celsius.

From this, it can be seen that the temperature increase control characteristic of the sample of the example is approximately the Curie temperature, and is greatly influenced by the temperature change of the inductance.

Backyard soil An amorphous alloy powder having a composition of Fe5o-xCr, PH1C7 (atomic %) was produced in the same manner as in Example 3. The particle size of the powder was 63-11000a.

For each Cr content sample, the Curie temperature T C
Magnetic flux density BIOk at %10KOe, and 1000
Magnetic flux density B1° at e. The measurement results are shown in Figure 9.

From Fig. 9, as the Cr content increases, the Curie temperature Tc of the alloy decreases, and B1°k, 81°0
It can be seen that the value also decreases. In order for Tc to be within the range of 42-90°C, the Cr content in this system must be 11.5
~13.7 at%.

〔Effect of the invention〕

As detailed above, the temperature-sensitive amorphous alloy of the present invention has a Curie temperature as low as 42 to 90°C due to the increased amount of Ni added. Further, by adding Af, the Curie temperature can be lowered even if the amount of Ni added is suppressed, and at the same time, a decrease in the saturation magnetic flux density can be avoided.

Furthermore, by coating the surface of the temperature-sensitive amorphous alloy with a non-magnetic metal, the time required to raise the temperature to the treatment temperature can be shortened. Such an amorphous alloy of the present invention will not be heated above a predetermined temperature correlated with the Curie temperature even if the external magnetic field is increased. Therefore, the temperature of the affected area, such as cancer, can always be set at a desired level without requiring special control, and is effective in induction heating therapy such as cancer treatment.

The temperature-sensitive amorphous alloy of the present invention contains Cr and/or Mo.
It has a low Curie point of 42-90°C due to the addition of .

Furthermore, by coating the surface with a non-magnetic metal, the heating rate can be increased and the heat generation efficiency can be increased. Such an amorphous alloy of the present invention will not be heated above a predetermined temperature correlated with the Curie temperature even if the external magnetic field is increased. Therefore, the temperature of the affected area, such as cancer, can always be set at a desired level without requiring special control, and is effective in induction heating therapy such as cancer treatment.

In summary, the present invention improves the temperature rise characteristics during heating due to the surface coating due to heat generation by eddy current in an alternating magnetic field, and significantly shortens the time required to reach the treatment temperature.

Furthermore, the noble metal coating can also prevent the outflow of metal ions that are considered harmful to living organisms.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an apparatus for measuring the temperature rise characteristics and magnetic properties of the temperature-sensitive amorphous alloy powder of the present invention, and Figs. FIG. 3 is a graph showing the relationship between the particle size and temperature rise characteristics of the temperature-sensitive amorphous alloy powder, and FIGS. 3 and 7 are graphs showing the particle size and temperature rise characteristics of the temperature-sensitive amorphous alloy powder of the present invention. FIG. 4 is a graph showing the relationship between each temperature and inductance of the temperature-sensitive amorphous alloy powder of the present invention, and FIG. 5 is a graph showing the relationship between the Ni content and Curie of the temperature-sensitive amorphous alloy powder of the present invention. FIG. 8 is a graph showing the relationship between each temperature and inductance, and FIG. 9 is a graph showing the relationship between Cr content and Curie temperature. In the figure: 1-Non-magnetic vibrator, 2-Exciting coil, agent: Hideaki Kuwahara, patent attorney.Figure C: Contained amount (at%) (Voluntary) Procedural amendment form 1991 August 2A,

Claims (3)

[Claims] (1) Contains one or more transition metals of Fe, Ni, and Co and one or more metalloids of P, C, Si, and B, and has a Curie temperature of 42°C to 90°C 1. A temperature-sensitive amorphous alloy for thermotherapy, characterized in that the surface of the alloy is coated with a non-magnetic metal. (2) The temperature-sensitive amorphous alloy for thermotherapy according to claim 1, characterized in that a small amount of Al is added thereto. (3) The temperature-sensitive amorphous alloy for thermotherapy according to claim 1, which contains Cr and/or Mo.