JPH01296125A - Sound speed measurement for ceramics molded product under high temperature - Google Patents

Abstract

PURPOSE:To enable quick measurement of sound velocity for various samples, by bonding a pressed end face of an ultrasonic guide bar on a contact medium and a sample on the contact medium separately with an organic adhesive. CONSTITUTION:An ultrasonic wave guide bar 1 is formed into a round bar from quartz glass as material and a pressed end face 1a ground mirror-finished at one end thereof perpendicular to the axis of the bar. A sample stabilizing body 2 is provided as opposed to the pressed end face 1a of the guide bar 1 to grasp a sample 13 in an area facing it. The stabilizing body 2 is formed into a cylinder using a ceramics as material. The guide bar 1 is advanced or retracted with a forward/backward mechanism 4 into and from a high temperature furnace 3. A contact medium 5 is made in a foil as comprising a malleable metal or an alloy thereof and bonded on the pressed end face 1a of the guide bar 1 and the sample 13 with an organic adhesive. This makes the contact closer in an interface thereby enabling an immediate measurement without a preheat treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for measuring the sound velocity (sound propagation velocity) in a ceramic molded article.

[Prior Art] Ceramic molded products such as engine blocks and refractory bricks are used in high-temperature environments.

Moreover, when using it, mechanical vibrations, traffic vibrations, earthquakes, etc.
Subject to other dynamic loads. Therefore, as a guideline for the strength of these ceramic molded products, regarding the usage temperature and each environmental temperature until the temperature rises to the usage temperature,
It was necessary to measure the dynamic elastic modulus of each. The same thing can be said when roof tiles, tiles, etc. are used under harsh conditions, and when there are problems during their manufacture.

By the way, the dynamic elastic modulus can be derived from the relationship between the density of the ceramic molded product and the sound velocity value. To do this, it is necessary to measure the sound velocity value in ceramic molded products in a high-temperature environment, but conventionally, there is no equipment that can easily measure the sound velocity in a high-temperature environment. Ta.

Therefore, the present inventors have developed a new sound velocity measurement device for ceramic molded products that enables the measurement of the sound velocity of ceramic molded products in a high-temperature environment, and that allows the measurement to be performed easily and repeatedly. 62-66500 (hereinafter referred to as the prior application device).

The gist of the device of the prior application is a heat-resistant ultrasonic waveguide rod having one end formed with a pressing end surface for a sample of a ceramic molded product and an ultrasonic transmitting/receiving device attached to the other end, and the ultrasonic waveguide. A sample stabilizer supported by a support provided with a universal joint and provided opposite to the pressing end surface of the rod, and a sample clamping area formed between the pressing end surface of the ultrasonic waveguide rod and the sample stabilizer. A high-temperature furnace for heating, a movement mechanism for advancing and retracting either or both of the ultrasonic waveguide or the sample stabilizer, and a malleable metal or alloy thereof to be coated on the pressed end surface of the ultrasonic waveguide. It consists of a foil-like couplant material.

In the device of the prior application, the ultrasonic waves emitted from the ultrasonic transmitter/receiver propagate through the ultrasonic waveguide rod and reach the sample of the ceramic molded article. The reflected waves from the front and back surfaces of the sample propagate through the ultrasonic waveguide again and return to the ultrasonic transmitter/receiver, but the returned waves become multiple pulsed sound waves due to the thickness of the sample. ing. Therefore, by measuring the time difference between each pulsed sound wave, the desired sound velocity value can be obtained. Since the sample can be placed in a desired high-temperature environment by heating in a high-temperature furnace, sound velocity values under each high-temperature environment can be obtained. Note that the sample stabilizer that holds the sample in cooperation with the ultrasonic waveguide rod is provided with a universal joint at its support portion. The universal joint portion is for increasing the adhesion of the sample to the pressing end surface of the ultrasonic waveguide rod.

By the way, what is required for a device that measures the speed of sound is that both the pressing end surface of the ultrasonic waveguide and the sample are in close contact with each other.
The aim is to prevent absorption attenuation and diffusion of ultrasonic waves between the two, but this must be ensured even at high temperatures. In addition, this type of measuring device also needs to be able to easily exchange samples. In order to solve both of these requirements, the device of the prior application:
A foil-shaped couplant was applied to the pressed end surface of the ultrasonic waveguide rod. The couplant is made of a malleable metal or an alloy thereof and forms a close contact along the rough surface of the sample.

The couplant never fuses with the ultrasound waveguide and sample even after being heated to high temperatures, so it can be easily removed, making repeated sound velocity measurements extremely simple.

[Problems to be Solved by the Invention] In the above-mentioned pre-order device, a couplant such as aluminum foil is interposed between the pressing end surface of the ultrasonic waveguide rod and the sample, but it does not come into contact with the pressing end surface and the sample. In order to make close contact with the medium, it was necessary to perform a preliminary heat treatment to maintain the temperature at approximately 500° C.×1 hr with the couplant sandwiched between the samples prior to measurement. This preliminary heat treatment required about 4 hours or more in total, including the time for raising and lowering the temperature, resulting in a long measurement time.

In addition, with the device of the prior application, it was not possible to measure porous samples and inhomogeneous objects (such as tiles) with a porosity of 30% or more because the attenuation of ultrasonic waves at the interface between the pressed end surface and the sample and within the sample was large. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a method that can more quickly measure the speed of sound for various samples using the device of the prior application.

[Means for Solving the Problems] The method of the present invention is a method of measuring the speed of sound in a sample using the device of the prior application, in which the pressing end surface of the ultrasonic waveguide and the couplant, and the couplant and the sample are each It is attached using an organic adhesive.

In the present invention, it is preferable that the adhesive has low viscosity and spreadability, and can be spread thinly and uniformly on the contact interface. Specific examples include cyanoacrylate adhesives, acrylic adhesives, and polyester adhesives.

As the couplant, aluminum foil, platinum foil, etc. are particularly suitable, as in the device of the prior application, but copper foil, etc. are also suitable. The thickness of the couplant foil is preferably 30 μm or less, particularly 1 to 20 μm.

[Operation] By interposing the adhesive between the pressed end surface of the ultrasonic waveguide and the couplant, as well as between the couplant and the sample, the contact at these interfaces becomes close, allowing immediate measurement without preheating. It can be performed.

Note that when the sample is exposed to high temperatures during measurement, the organic adhesive will carbonize, but the resulting carbon particles will remain and distribute uniformly at the contact interface, allowing the pressed end surface to bond with the couplant and the couplant. Close contact with the sample is maintained, allowing accurate sound velocity measurements even at high temperatures.

Moreover, since the adhesive is carbonized in this way, the couplant is easily peeled off from the pressed end surface and the sample after the measurement is completed.

[Examples] The present invention will be described below based on drawings showing examples thereof.

First, the configuration of the measuring device will be explained. FIG. 1 is a partially cutaway side view of the measuring device. This measuring device mainly includes an ultrasonic waveguide rod 1, a sample stabilizer 2, a high temperature furnace 3, an advancing/retracting mechanism 4, and a couplant 5 (see FIG. 2). This measuring device is mounted on a pedestal 10,
Each of the above-mentioned constituent bodies is arranged integrally.

The ultrasonic waveguide rod 1 is made of quartz glass and is formed into a round rod shape. Quartz glass has extremely high propagation of ultrasonic waves and excellent heat resistance. At one end of the ultrasonic waveguide rod 1, a pressed end surface 1a that is perpendicular to the axis of the rod and polished to a mirror finish is formed. A female screw 1b is carved on the outer peripheral surface of the ultrasonic waveguide rod 1 over its entire length.

The female thread 1b is a measure for removing delayed waves (refracted waves) of longitudinal waves. 6 is installed. Although not shown in the drawings, an echo removal device, an oscilloscope, etc. are connected to the ultrasonic transmitting/receiving device 6, and the whole constitutes an ultrasonic measurement system based on the pulse echo method.

The sample stabilizer 2 is attached to the pressed end surface 1 of the ultrasonic waveguide rod 1.
The sample 13 is held in the opposing area. The sample stabilizer 2
is formed into a cylindrical shape made of ceramics (
(The cylinder hole is indicated by a dashed line). In addition, the sample stabilizer 2 includes:
The support portion 7 is provided with a universal joint portion 8. The universal joint portion 8 has a cylindrical opening edge of the sample stabilizer 2, a true sphere 8a made of alumina, and a cylindrical hole opening edge of a cylindrical member 8b having a shape similar to that of the sample stabilizer 2, which are connected to each other. It is made by joining. Therefore, by pressing the ultrasonic waveguide rod 1 against the sample stabilizer 2 through the sample 13, the pressing end surface 1a of the ultrasonic waveguide rod 1 and the sample 13 come into contact, and the sample 13 and the sample stabilizer 2 are brought into contact with each other. come into close contact with each other. The stand 9 that holds the support 7 horizontally is movable in the direction along the axis of the ultrasonic waveguide 1, so that the holding position of the sample 13 can be adjusted back and forth. .

The high-temperature furnace 3 is an electric furnace, and its head is inserted into the furnace so that about half of the ultrasonic waveguide rod 1 and about half of the support 7 for the sample stabilizer 2 are positioned. The temperature inside the furnace is such that the temperature distribution is highest in the sample clamping region between the pressing end surface 1a of the ultrasonic waveguide rod 1 and the sample stabilizer 2. A desired high-temperature environment can be obtained within the furnace temperature within a range of up to 100°C.

The advancing/retracting mechanism 4 advances and retreats the ultrasonic waveguide rod 1 in the inner and outer directions of the high temperature furnace 3, and in this embodiment, the
An air cylinder whose pressing force can be varied within a range of 1.3 MPa is used. If you use an air cylinder, sample 13
Since it can absorb minute thermal expansion when heated, it has the advantage of being able to measure sound velocity values with less error. In addition, in this embodiment, a floating connector 11
This allows the installation posture of the ultrasonic waveguide rod 1 to be slightly adjusted.

As shown in FIG. 2, the couplant 5 is adhered to the pressing end surface 1a of the ultrasonic waveguide rod 1 and to the sample 13 using an organic adhesive. The couplant 5 is a foil made of a malleable metal or an alloy thereof. In the measurement values described below, aluminum foil having a thickness of 15 μm was used.

The melting point of the couplant 5 made of this material is 600° C. or higher, and there is no fear that the couplant will melt and bond with the ultrasonic waveguide rod 1 and the sample 13 even when heated in the high-temperature furnace 3.

In addition, since the organic adhesive is carbonized with heating, after cooling, the pressed end surface 1a of the ultrasonic waveguide rod 1 and the sample 1
The couplant can be easily removed from 3.

By inserting the sound velocity value measured by such a device into the following equation, the dynamic elastic modulus (E) of the ceramic molded product in a high-temperature environment can be determined.

E=2ρ・Vs2(1+ν) However, ρ: Density of the sample ν: Poisson's ratio s: Transverse wave sound velocity value shi= Longitudinal wave sound velocity value In addition, by inserting each of the above sound velocity values into the following equation, the ceramic molded product Bulk modulus under each environmental temperature (
B) and rigidity (G) can also be determined.

B=ρ(VL2−−Vs　2) G = ρ Vs 2 Next, a measurement example will be explained.

Measurement Example 1 A commercially available aluminum foil (thickness: 15 μm) was used as a couplant. This couplant (size 3x
3 cm) was adhered to the pressing end surface of the ultrasonic waveguide rod using a commercially available cyanoacrylate adhesive. The pressing end surface of the ultrasonic waveguide rod was a circular surface with a diameter of 27 mm, and about 5 mg of adhesive was used.

Next, this couplant and the sample were bonded together using about 5 mg of the above adhesive. The sample was made of alumina (A) with a porosity of 3%.
1g203) m solid, diameter 2am, height 1cm
It has a cylindrical shape with a size of , and the adhesion area with the couplant is about 3 crn'.

Set this sample in the measuring device as shown in Figure 1.2,
The sound velocity was measured while raising the temperature at 3°C/min. The frequency of the ultrasonic wave is 5MHz, the measurement temperature is room temperature,
The temperatures were 100°C, 300°C, 400°C and 500°C.

The results are shown in Table 1, and Young's modulus E calculated from the measured values is shown in FIG.

Measurement Example 2.3.4 Samples with porosity of 13% (Measurement Example 2) and 25% (
Measurement was carried out in the same manner as in Measurement Example 1 except that 3) and 38% (4) were used. The results are shown in Table 1 and Figure 3.

Measurement Example 5.6 Samples with porosity of 8% (Measurement Example 5) and porosity of 21
Measurement was carried out in the same manner as in Measurement Example 1 except that a ceramic tile piece measuring 3×3×0.6 cm was used. The results are shown in Table 1 and Figure 4.

Comparative Example 1.2.3 The same procedure as Measurement Example 1.2.3 was carried out except that the contact surface between the couplant, the pressed end surface, and the sample was treated by preliminary heat treatment at 500° C. for 1 hr without using an adhesive. The speed of sound was measured. The results are shown in Table 1.

From Table 1 and Figure 3.4, it is clear that according to the method of the present invention, the sample with a high porosity (porosity of 38
%) and heterogeneous bodies (tiles).

Table 1: Note that the advancing/retracting mechanism 4 shown in the device of FIG. 1 is not limited to using an air cylinder, but may also use a cylinder or the like whose driving source is oil pressure, water pressure, or voltage. Furthermore, the high-temperature furnace 3 is not limited to an electric furnace, and can be changed to various other heating devices. The ultrasonic measurement system mainly consisting of the ultrasonic transceiver 6 is configured to perform a pulse echo method, which includes the pulse super position method and the pulse echo overlap method. , phase comparison method, singalanland method, etc., and the apparatus of the present invention may be implemented using any of these methods. In this way, the configuration and shape of the device of the present invention can be changed as appropriate depending on the embodiment.

[Effects of the Invention] As described above, according to the method of the present invention, it is possible to extremely quickly measure the speed of sound in a high temperature environment for various samples. In particular, the method of the present invention has the excellent effect of accurately determining the sound velocity even in porous and heterogeneous materials.

[Brief explanation of the drawing]

Fig. 1 is a partially cutaway side view of the device of the present invention;
The figure is an enlarged side view showing how the sample is held, and FIGS. 3 and 4 are graphs showing measurement values obtained by the apparatus of the present invention. 1... Ultrasonic waveguide rod, 1a... Pressing end surface, 2...
...Sample stabilizer, 3.High-temperature furnace, 4.Advancing/retracting mechanism, 5.Couplant, 6.Ultrasonic transmitting/receiving device, 7.Support, 8.Universal joint part ,
13 river samples. Patent applicant Inax Co., Ltd. Ultrasonic Industry Co., Ltd. Agent Patent attorney Tsuyoshi Shigeno Figure 3 Temperature (°C)

Claims (1)

[Claims] (1) A heat-resistant ultrasonic waveguide rod having one end formed with a pressing end surface for a sample of a ceramic molded product and an ultrasonic transmitting/receiving device attached to the other end; a sample stabilizer supported by a support provided with a universal joint; a high-temperature furnace for heating a sample holding area formed between the pressing end surface of the ultrasonic waveguide rod and the sample stabilizer; Using a device having a reciprocating mechanism for advancing or retracting either the ultrasonic waveguide or the sample stabilizer, or both, a foil couplant made of a malleable metal or an alloy thereof is placed between the pressed end face and the sample. sandwiching a sample between the pressing end face of the ultrasonic waveguide rod and the sample stabilizing rod, emitting ultrasonic waves from the ultrasonic transmitter/receiver toward the sample, and receiving reflected waves from the sample; A method of measuring the speed of sound in a sample from the time difference between a radiation method and a reflected wave, the method comprising bonding the pressed end surface of the ultrasonic waveguide to the couplant and the couplant and the sample using an organic adhesive, respectively. A method for measuring the sound velocity of ceramic molded products under high temperature.