JP2000219568A - Ceramic article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to easily and efficiently measure or examine the internal structure by making a tubular or stick-like article using an infrared ray transmissive ceramics which is opaque to visible light and has specific transmissivity to specific wavelengths of infrared-rays. SOLUTION: A tubular or stick-like ceramic article opaque to visible light is made of an infrared ray transmissive ceramics having a transmissivity of >=45% at the thickness of 1 mm for the infrared ray having the wavelength of 1,550 nm and made incident from air. The ceramic articles are preferably prepared by using infrared ray transmissive ceramics which satisfy the following relations: (1-R)2>=0.84 and μ<=0.7/mm, wherein R is reflectance at the wavelength of 1,550 nm, and μ is total of a reflection coefficient and absorption coefficient. The infrared ray transmissive ceramics is selected from the ceramics in a narrow sense (such as alumina, zirconia or the like) as well as the ceramics in a wide sense (such as opal glass, colored glass or the like).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tubular or rod-shaped ceramic article.

[0002]

2. Description of the Related Art Ceramic materials are widely used in various industries. In particular, precision-shaped tubular or rod-shaped ceramic parts, including precision capillaries with minute internal holes, are used for optical and electronic components, or their fixing members, guide members, alignment members, reinforcing members, coating members, and connections. Many products have been commercialized as members. In the production of such precision parts, it is important to accurately measure internal dimensions such as inner hole dimensions and to detect internal defects such as bubbles and cracks.

[0003]

In the case of a material that is transparent to visible light, the measurement of internal dimensions and the detection of defects can be easily performed by using an optical measuring device. However, since ceramic materials are generally opaque to visible light, such means cannot be used.

[0004] For this reason, various precision gauges must be used for measuring the dimensional accuracy, so that there is a problem that the inside of the gauge cannot be measured and that the measurement is troublesome. In addition, methods that use ultrasonic waves or radiation are often used for detecting internal defects, but all of these methods have problems in that the measuring device is complicated or the inspection efficiency is low.

An object of the present invention is to provide a tubular or rod-shaped ceramic article which is opaque to visible light, but can easily and efficiently measure and inspect the internal structure.

[0006]

The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, some of the ceramics are opaque to visible light but transparent to infrared light. In addition, it has been found that tubular and rod-shaped objects manufactured using such infrared-transmitting ceramics can easily measure and inspect the internal structure by using infrared light, and propose the present invention. Reached.

That is, the ceramic article of the present invention is a tubular or rod-shaped ceramic article that is opaque to visible light and has a transmittance of 45% or more, preferably 1% or more, of infrared rays having a wavelength of 1550 nm incident from the air at a thickness of 1 mm. It is characterized by being made of infrared transmitting ceramics of 60% or more.

In the present invention, "opaque to visible light" means that it is difficult to measure or inspect the internal structure using visible light.
760 nm), the average transmissivity of the straight traveling light is 1 m in thickness.
m means 50% or less.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION The ceramic article of the present invention is made of an infrared transmitting ceramic which is opaque to visible light. The infrared transmittance has a thickness of 1 at a wavelength of 1550 nm.
It is 45% or more in mm. Here, the reason for paying attention to the infrared transmittance at a wavelength of 1550 nm will be described. In order to use infrared light for measurement and inspection, light emission and light receiving parts of infrared laser are required.
1310 nm, 1550 nm, and the like. In general, the longer the wavelength, the lower the resolution of the measurement, and the lower the measurement accuracy. However, the longer the wavelength, the more advantageous it is for transmitting light through ceramics. According to the study by the present inventors, it has been found that when a light receiving / emitting component having a wavelength of 1550 nm is used, a sufficient amount of transmitted light for measurement can be easily obtained while ensuring measurement accuracy of submicron. If the transmittance of infrared light at 1550 nm is 45% or more at a thickness of 1 mm, accurate measurement and inspection can be performed using infrared light of this wavelength.

When measuring or inspecting the article of the present invention, it is not always necessary to use infrared rays of 1550 nm. In other words, depending on the required accuracy of measurement or inspection, the infrared transmission characteristics of ceramics, and the like, it may be more advantageous to use infrared light of another wavelength than infrared light of 1550 nm.

The ceramic article of the present invention has
When the reflectance at 0 nm is R and the sum of the reflection coefficient and the absorption coefficient is μ, (1−R) ² ≧ 0.84 and μ ≦
Preferably, the condition of 0.7 / mm is satisfied. The reason is shown below.

The relationship between the transmittance T and the thickness L is given by T = Aex
It is represented by the equation of p (-μL). The constant A is (1-R)
Replaced by ² . As is apparent from this equation, when the thickness L of the material is constant, the transmittance is determined by the constants A and μ. There are countless combinations of A and μ such that the transmittance T is 45% or more when the thickness L is 1 mm, but when A is less than 0.84 or when μ is greater than 0.7 / mm. When the thickness L is large, the transmittance significantly decreases. Articles made of such materials are therefore 1550
The range that can be measured and inspected with infrared light of nm is limited to those having a small wall thickness, which is not practical.

The infrared transmitting ceramics are not specifically limited to ceramics in a narrow sense (alumina, zirconia, etc.) but include ceramics in a broad sense including glass (milky glass, colored glass, etc.) and glass ceramics. Become. The infrared transmittance of these materials can be adjusted by various methods. For example, in the narrow sense of ceramics and glass ceramics, the grain size of precipitated crystals and the difference in refractive index from the matrix phase are controlled, and in opalescent glass, the particle size of heterogeneous particles caused by phase separation and the difference in the refractive index of each phase are controlled. Thus, the infrared transmittance can be adjusted.

A method for manufacturing each material will be described below.

In the case of ceramics in a narrow sense, for example, a crystal whose crystal system belongs to a tetragonal system, such as zirconia, or a crystal having a small birefringence even in a hexagonal system, such as alumina, is subjected to a hot pressing method at 1300 to 1800 ° C. What is necessary is just to shape | mold and sinter so that a bubble may be reduced as much as possible.

In the case of a glass-ceramic material, for example, SiO _{2 is} 60 to 75% by weight and Al ₂ O _{3 is} 15 to 28.
_{%, Li 2 O 1.8~5%,} K 2 O 0~10%, Ti
A glass containing 1.5 to 5% of O _{2 and} 0 to 4% of ZrO ₂ is heat-treated in the range of 900 to 1250 ° C. to crystallize,
-Quartz solid solution, β-spodumene solid solution or the like precipitated, SiO ₂ 50 to 80%, Li ₂ O 8 to 13
_{%, P 2 O 5 1~4%} , Al 2 O 3 1~11%, ZnO
Glass containing 0-7% and 0-6% K ₂ O
Crystallized at 0 to 1100 ° C. to precipitate lithium silicate, quartz, cristobalite and the like can be used. In these glass ceramics, in most cases, a crystal phase and a glass phase are mixed, but in order to reduce the refractive index difference between the crystal phase and the matrix phase, a metal element, a semiconductor element, or the like is added to the glass as an additive. By adding this, the transmittance of infrared rays can be improved. Here, it is not necessary to consider the abundance ratio between the crystal phase and the glass phase.

In the case of a glass material, for example, SiO
₂ 60-70%, Al ₂ O ₃ 3-14%, B ₂ O ₃ 1
~4%, BaO 1~3%, 0~5 % ZnO, Na 2
Phase-separated opalescent glass containing 10-22% O can be used.

In any case, in order to obtain good infrared transmission characteristics, it is preferable that the particle size of precipitated crystals and foreign particles be 3 μm or less, and that the difference in refractive index be as small as possible. In the case of glass and glass ceramics, it is also possible to adjust the infrared transmittance by controlling the content of colored ions having absorption in the infrared region.

When the ceramic article of the present invention is used for precision parts such as electronic parts, as infrared transmitting ceramics, strictly defined ceramics having precipitated crystals of zirconia, alumina, etc., β-quartz solid solution, β-spodumene solid solution It is desirable to use glass ceramics having lithium silicate or the like as precipitated crystals. These materials have excellent mechanical, thermal and chemical properties and are suitable for precision parts.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments.

Table 1 shows examples of the present invention (samples No. 1 to No. 1).
5) and Table 2 show comparative examples (sample Nos. 6 and 7).

[0022]

[Table 1]

[0023]

[Table 2]

First, an opaque ceramic material as shown in the table was prepared and processed into a cylindrical shape having a diameter of 2.5 mm and a length of 10 mm, and an inner hole having a diameter of 0.1 mm was formed by ultrasonic processing to form a capillary. A sample was prepared.

Sample No. The ceramic material used for the production of 1, 2, and 6 was Li ₂ O—Al ₂ O ₃ —SiO
_{It is a 2} type glass ceramic, and it is Li ₂ O-Al ₂ O ₃
2 hours -SiO ₂ glass, at 950 ° C., respectively, 1
It is crystallized by heat treatment at 000 ° C. for 1 hour and 1200 ° C. for 2 hours. Sample No. The ceramic material used in Example ₃ is an opalescent glass made of a Na ₂ O—Al ₂ O ₃ —SiO ₂ system glass. The raw materials are melted at 1550 ° C., and then gradually cooled to separate the glass to separate different particles. Is generated. Sample No. The ceramic materials used in 4, 5, and 7 were alumina ceramic and zirconia ceramic, and were prepared by adding a binder to the raw materials, kneading the mixture, and then sintering by hot pressing.

The infrared transmittance in the table indicates that the wavelength is 1550.
The laser light of nm was applied to the sample, and the amount of transmitted straight light was measured. The average visible light transmittance was determined by irradiating a sample with visible light of 380 to 760 nm using a spectrophotometer and measuring the amount of transmitted straight light. The constant A was obtained by measuring the refractive index of the sample and using the following equation. Here, n ₁ indicates the refractive index of air and n ₂ indicates the refractive index of the sample.

R = {(n ₁ −n ₂ ) / (n ₁ + n ₂ )} ² A = (1−R) ^{2 The} constant μ is calculated from the infrared transmittance T, the constant A, and the sample thickness L as follows. It was determined by the formula.

Μ = ln (A / T) / L The particle size of the precipitated crystals or foreign particles was measured using a scanning electron microscope.

Next, each sample was evaluated as to whether or not the inner hole measurement by infrared rays was possible. This evaluation was performed at 1550 nm
Was scanned in the diameter direction of the sample, and the transmittance distribution with respect to the position in the diameter direction of each sample was measured.
Next, based on this transmittance distribution, those in which the inner diameter portion could be clearly identified (FIG. 1) were rated as 、, and those in which identification was difficult (FIG. 2) were rated as x.

As a result, in each of the samples manufactured using the ceramic material having a high infrared transmittance, the inner hole measurement by infrared was possible. On the other hand, in each sample of the comparative example made of a material having a low infrared transmittance, the inner hole measurement was impossible.

These facts show that the ceramic article of the present invention can measure and inspect the internal structure by infrared rays at 1550 nm.

[0032]

As described above, the ceramic article of the present invention can measure the internal dimensions and inspect internal defects such as bubbles and cracks by an optical method. For this reason, it is suitable as an optical component or an electronic component that is free from defects and requires precise dimensional accuracy, or a precision component such as a fixing member, a guide member, an alignment member, a reinforcing member, a covering member, a connection member, or the like. .

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing a cross-sectional transmittance distribution of a capillary sample capable of measuring an inner hole.

FIG. 2 is an explanatory diagram showing a cross-sectional transmittance distribution of a capillary sample in which inner hole measurement is impossible.

Claims (2)

[Claims] 1. A tubular or rod-shaped ceramic article which is opaque to visible light.
The transmittance of infrared light of 550 nm at a thickness of 1 mm is 45.
% Or more of infrared transmitting ceramics. 2. When the reflectance at 1550 nm is R and the sum of the reflection coefficient and the absorption coefficient is μ, (1-R) ² ≧
2. An infrared transmitting ceramic material which satisfies the condition of 0.84 and μ ≦ 0.7 / mm.
Ceramic articles.