JPH0317248A - Manufacturing method of magnetostrictive actuator - Google Patents

Abstract

PURPOSE:To obtain the magnetostriction working body having high static magnetostriction by working a Pd-Co alloy having specified compsn. into a wire shape or a thin sheet shape by hot working and cold working and thereafter executing heat treatment under specified conditions. CONSTITUTION:An ingot of a Pd-Co alloy constituted of, by weight, 40 to 92% Pd and 60 to 8% Co is hot forged in the temp. range of 900 to 1400 deg.C and is successively cold rolled to work into a wire shape or a thin sheet shape, which is heated in the temp. range of 900 deg.C to the m.p. of the alloy for about 1min in the air, in an inert gas atmosphere or in vacuum and is thereafter slowly cooled to a room temp. at an arbitrary cooling rate. The magnetostriction working body having -40 to 170X10<-6> static magnetostriction and therefore suitable to structural body elements such as magnetostriction sensor elements and magnetostriction vibrator elements for ultrasonic generation can be obtd.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is an element for a magnetostrictive sensor used in a load cell, a force meter for measuring pressure, tension, etc., and an element for a magnetostrictive vibrator for generating ultrasonic waves. Alternatively, the present invention relates to a method for manufacturing a magnetostrictive actuator having large magnetostriction, which is useful as an element of a structure that utilizes magnetostriction, such as a magnetostrictive bimetal.

(Prior art) In recent years, in the field of force measurement using metal magnetostrictive materials, with the rapid progress in automation, miniaturization, and labor saving of various processes and devices, improvements in sensor reliability and high precision have been made. There was a demand for miniaturization and miniaturization.

As a magnetostrictive material that can meet these diverse needs, firstly, it has large magnetostriction and can provide a large signal output, and secondly, it has good cold workability and can be formed into the desired shape. Thirdly, it is necessary that the amount of strain be expressed in a low magnetic field.

(Problem to be solved by the invention) Conventionally, the magnetostrictive material used for force measurement is Ni.
, Fe-Ni alloy, Fe-Si alloy or Fe-Af
Metals and alloys such as f alloys are used depending on the purpose.

The saturation magnetostriction value of these magnetostrictive materials is 1l/1ξ−3 of Ni.
The value is about 5×10-” (1=length) or smaller, and some alloys have poor cold workability.

In the present invention, it has been discovered that with a specific composition of a palladium-cobalt alloy, a large magnetostriction characteristic that far exceeds the magnetostriction value of conventional magnetostrictive materials can be developed by simple heat treatment or processing. The purpose is to be easy to cold work and have a magnetostatic strain of -40.
The object of the present invention is to provide a new material which has a value of ˜-1.70 XIO-'' and is fully suitable for use as a magnetostrictive actuator.

(Means for Solving the Problems) The present invention consists of an alloy consisting of 40 to 92% palladium and 60 to 8% cobalt by weight and containing a small amount of impurities at a temperature of 900°C to 1400°C. After hot working and then cold working into a desired shape such as a wire rod or thin plate material, it is heated in air, in an inert gas, or in a vacuum at a temperature of 900°C or more and the melting point or less for 1 minute or more, and then optionally The magnetostatic strain is -40 to -1.
70 XIO-'.

(for production) Next, a method for producing the alloy of the present invention will be explained.

First, palladium and Kobal I having the above composition range are melted in a conventional melting furnace in air, an inert gas, or a vacuum, and then sufficiently stirred to produce a compositionally uniform molten alloy. Next, this is poured into a mold to make an ingot, which is then subjected to hot working such as forging, rolling, or swaging at a temperature of 900°C to 1400°C, and then cold worked at room temperature or above room temperature. Process and shape the material to suit the purpose. This certain shape is 90
The product is heated and maintained at a temperature of 0°C or higher and lower than the melting point, for example 1000°C, for 1 minute or more, usually for about 1 hour, and then slowly cooled to form a product. Next, examples of the present invention will be described.

Example Palladium and cobalt were prepared in a Tammann furnace (electric resistance furnace)
The molten metal was melted in an alumina crucible with an inner diameter of about 10 mm while passing argon gas through it, and the molten metal was thoroughly stirred, then sucked into a quartz tube with an inner diameter of about 3 mm and cooled. Next, it was swaged at room temperature to a diameter of 2 mm.
A sample with a length of about 10 cm was cut from this round offering. Then, after heating it at 1000°C for 1 hour,
The sample was cooled at a rate of 00°C/hour and used as a measurement sample. The longitudinal magnetostriction of the sample in the longitudinal direction was measured using an optical lever type device having two rotors. On the other hand, an ingot made by pouring the molten alloy into an iron mold was hot forged and cold rolled into a thin plate of approximately 0.2 mm. From this thin plate, the inner diameter is 3
An annular sample with a diameter of 3 mm and an outer diameter of 45 mm was punched out and subjected to the same heat treatment as the round bar sample to obtain a sample for measuring dynamic magnetostriction characteristics. The dynamic magnetostriction characteristics were measured using an ordinary Maxwell bridge system.

Table 1 shows the longitudinal magnetostriction values of the present invention example at an applied magnetic field Hex=1.2 koe and the saturation magnetostriction values of the three conventional alloys.

Table 1 Figure 1 shows the weight percentage of palladium and cobalt among the measurement results: 57% = 43%, 77% = 23%, 80%.
:20%. 82%: 18% and 90%: lO%
The relationship between the longitudinal magnetostriction value and the applied magnetic field Hex is shown for alloys having each composition and for nickel as a comparative example. These results show that the longitudinal magnetostriction of the magnetostrictive actuator of the present invention is larger than that of nickel in all compositions, and in particular, the value of the magnetostrictive actuator with 82% palladium and 8% cobalt I is higher than that of nickel in a magnetic field of 11000 e. It can be seen that it exhibits a large value of -167 XIO-', which is about five times as large.

Figure 2 shows various magnetostrictive actuators in the composition range of the present invention, 100 0e, 200 0e, and 12000e.
The longitudinal magnetostriction value when an applied magnetic field is applied is shown.

That is, cobalt in any applied magnetic field! 5～
It is maximum at 20%.

FIG. 3 shows the relationship between the maximum value (λ/H ex) max of the ratio of the longitudinal magnetostriction of the magnetostrictive body of the present invention to the applied magnetic field and the concentration. Here, (λ/Hex) maX is -1.1 to -1.5 for alloys containing tto ~20% cobalt.
xlO-@oe-', which is comparable to or greater than that of nickel. Especially for alloys with cobalt content of 1896 -1.53X 10-'O
e-', which is approximately 1.5 times larger than nickel. Note that in a magnetostrictive vibrator, the value of the electromechanical coupling coefficient k, which is a figure of merit, is also important, and the results of measuring this for an alloy of 82% palladium and 18% cobalt are shown in FIG. As shown in the figure, k of the magnetostrictive actuator of the present invention is small when the DC deflection magnetic field is about 350e or less when compared with nickel, or becomes larger than k of nickel when the DC bias magnetic field exceeds about 350e.

As explained above in detail, the magnetostrictive actuator of the present invention can also be used as an element for a magnetostrictive vibrator. In addition, the magnetostrictive actuator of the present invention not only exhibits a very large saturation magnetostriction value, but also consists of a single solid solution of face-centered cubic crystals, so cold or hot working is extremely easy, and it can be formed into any shape. It is possible to obtain a precept form. This is also a great advantage when manufacturing thin plates such as magnetostrictive vibrators and magnetostrictive bimetals.

Finally, the reason why palladium is limited to 40 to 92% in the present invention is that when palladium is below 40% and above 92%, the absolute value of the saturation value of magnetostriction is
This is because the value is smaller than the value greater than or equal to "-".

[Brief explanation of drawings]

Fig. 1 is a characteristic curve diagram showing the relationship between longitudinal magnetostriction and applied magnetic field of a magnetostrictive actuator based on palladium-cobalt, and Fig. 2 is a characteristic curve diagram showing the relationship between longitudinal magnetostriction and applied magnetic field of a magnetostrictive actuator based on palladium-cobalt. Figure 3 is a characteristic curve diagram showing the relationship between longitudinal magnetostriction and alloy concentration. Figure 3 is a characteristic curve diagram showing the relationship between (λ/Hex) max and alloy concentration of a palladium-cobalt magnetostrictive actuator. It is a characteristic curve diagram showing the relationship between the electromechanical coupling coefficient and the DC bias magnetic field of a magnetostrictive actuator made of 82% palladium and 18% cobalt. Fig. 1 0 200 400 600 500 /θω EPNrA jJj }-1eX (Oe) /7oo 1400 Fig. 2 Ko/ζru Fi4*(”.) Engraving of drawing (no change in content) 1!! >iviRi”fr 40 Hanawa (Oe) Figure 3 Kobaru}-Sapphire (%) Procedural amendment (method) July 2, 2017

Claims (1)

[Claims] 1. An alloy consisting of 40-92% palladium and 60-8% cobalt by weight and containing a small amount of impurities is
After hot working at a temperature of 0°C or higher and 1400°C or lower, and then cold working to form a desired shape such as a wire or thin plate, it is heated in air, in an inert gas, or in a vacuum for 90 minutes.
Heating for 1 minute or more at a temperature of 00℃ or higher and lower than the melting point, then slowly cooling at an arbitrary speed until the magnetostriction is -40 to -170
A method for producing a magnetostrictive actuating body, characterized in that a magnetostrictive actuating body is obtained.