JP2005156413A - Apparatus for evaluating characteristics of material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce measuring errors caused by the thermal expansion of a sample stand, in an evaluation apparatus for the characteristics of a material for evaluating the predetermined characteristics of the material by heating the sample. <P>SOLUTION: The evaluation apparatus for the characteristics of the material is so constituted as to press a penetrator (3) to the surface of the sample (S) to form a cavity to evaluate the characteristics of the material, on the basis of the cavity and equipped with a sample stand (2), on which the sample is mounted, a heating part (e.g., a heater 6) for heating the sample stand, a temperature sensor (7) for detecting the temperature of the vicinity of the sample on the sample stand and a temperature control means (e.g., CPU 13) for controlling the heating part, to control the temperature of the sample stand. The sample stand is constituted of ceramics. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a material property evaluation apparatus that forms a recess by pressing an indenter against a sample surface and evaluates a predetermined material property of a sample based on the recess.

  2. Description of the Related Art Conventionally, there has been known a material property evaluation apparatus that applies a load to a sample surface with an indenter to form a recess and evaluates a predetermined material property of the sample based on the recess. In recent years, a material property evaluation apparatus that measures a physical property value such as hardness while the sample is heated is also known, and the temperature dependency of the material property of the sample can be examined (for example, Patent Document 1). Such a material property evaluation apparatus is used in a micro hardness test for examining the temperature dependence of hardness of a thin film or the like.

  The material property evaluation apparatus described in Patent Literature 1 includes, for example, a sample table on which a sample is placed, a pressing mechanism that presses an indenter against the sample on the sample table, and a load detector that detects an indentation load of the indenter. A displacement detector for detecting the displacement amount of the indenter, a heating mechanism for heating the sample and the indenter on the sample table, a sample table heater for heating the sample, and the like are provided.

In the material property evaluation test, the sample is placed on the sample table, the indenter and the sample are heated by the heating mechanism, and at the same time, the sample table is entirely heated by heat conduction by the sample table heater. Next, when the sample reaches a set temperature, the indenter is pressed against the sample with a predetermined pressing pressure by the pressing mechanism, thereby forming a recess in the sample. The load detector detects the indentation load of the indenter, and the displacement detector detects the indentation displacement of the indenter, and measures physical property values such as hardness of the sample from the relationship between these values.
Japanese Patent Application Laid-Open No. 5-264428

  However, when the indenter is pushed into the sample, there is a problem that the sample stage may expand due to heating, resulting in a measurement error.

  Therefore, an object of the present invention is to reduce the measurement error caused by the thermal expansion of the sample stage during the operation of the indenter in the material property evaluation apparatus that heats the sample stage and evaluates the predetermined material characteristic of the sample, and thus more accurate. It is to provide a material characteristic evaluation apparatus capable of performing high material characteristic evaluation.

In order to solve the above-mentioned problem, as shown in FIG.
A material property evaluation apparatus for forming a recess by pressing an indenter (3) on the surface of a sample (S) and evaluating a predetermined material property of the sample based on the recess,
A sample stage (2) on which the sample is placed;
A heating unit (for example, heater 6) for heating the sample stage;
A temperature sensor (7) for detecting the temperature in the vicinity of the sample on the sample stage;
Temperature control means (for example, CPU 13) for controlling the temperature of the sample stage by controlling the heating unit based on the temperature detected by the temperature sensor;
With
The sample stage is made of ceramics.
Here, the predetermined material characteristics refer to, for example, material characteristics such as sample hardness, elastic modulus, adhesion force surface properties, and wear resistance characteristics.

Invention of Claim 2 is the material characteristic evaluation apparatus of Claim 1, Comprising:
Indentation depth measuring means (for example, displacement meter 9) for measuring the indentation depth when the indenter is formed is provided.

Invention of Claim 3 is the material characteristic evaluation apparatus of Claim 1 or 2, Comprising:
The material of the ceramic is boron nitride.

  According to the first aspect of the present invention, since the sample stage of the material property evaluation apparatus is made of ceramics, since the thermal expansion coefficient is small, the thermal expansion of the sample stage can be reduced. Therefore, the measurement error resulting from the thermal expansion of the sample stage during heating can be reduced, and the accuracy of the material property evaluation can be improved.

  According to the invention described in claim 2, it is of course possible to obtain the same effect as that of the invention described in claim 1. In particular, the indentation depth when the indentor is formed is measured by the indentation depth measuring means. Can do. Therefore, since the indentation depth can be calculated using this indentation depth as a parameter for evaluating material characteristics, it is possible to evaluate the material characteristics of a thin film or the like in which the indentation cannot be directly observed. In addition, among the material properties of the sample other than the hardness, the elastic properties, adhesion surface properties, wear resistance properties, and the like can be evaluated based on the indentation depth of the indenter.

  According to the third aspect of the invention, it is of course possible to obtain the same effect as that of the first or second aspect of the invention. In particular, since the ceramic material is boron nitride, the thermal expansion coefficient and the thermal expansion length. Therefore, the thermal expansion of the sample stage caused by heating during the operation of the indenter can be greatly suppressed. Therefore, the accuracy of material property evaluation can be significantly improved.

Hereinafter, a material property evaluation apparatus according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic diagram of a configuration of a material property evaluation apparatus according to the present invention, and FIG. 2 is a block diagram of a temperature control system of the material property evaluation apparatus of FIG.

  As shown in FIG. 1, the material property evaluation apparatus 1 includes a sample stage 2 on which a sample S is placed, an indenter 3 that forms a recess in the sample S, an indenter shaft 4 that includes an indenter 3 at the tip, and an indenter shaft. 4, a load loading mechanism 5 for applying a predetermined test force, a displacement meter 9 as an indentation depth measuring means for measuring an indentation depth when the indenter 3 is formed into a depression, and a temperature for controlling the temperature of the sample stage 2 The control part 10 and the hardness calculation part 20 etc. which calculate the hardness of the sample S are provided.

The sample stage 2 is made of ceramics, and includes a heater 6 as a heating unit for heating the sample stage 2, a temperature sensor 7 for detecting the temperature in the vicinity of the sample S, and the like. The ceramic material is preferably boron nitride. This is because boron nitride has a small coefficient of thermal expansion, for example, 0.8 × 10 ⁻⁶ . Further, the thermal expansion length when the temperature is changed by 1 ° C. is as small as about 1/100 of that of aluminum. Furthermore, it is suitable as a ceramic material constituting the sample table 2 in that it has high thermal conductivity and excellent corrosion resistance.

The load loading mechanism 5 includes a drive coil (not shown) disposed in the magnetic field, a power source (not shown) for supplying a drive current to the drive coil, and the like. The load load mechanism 5 has a configuration in which a predetermined test force is set based on an operation of the operation unit 8 and then a predetermined test force is generated by supplying a drive current to the drive coil. It has become.
Further, the load loading mechanism unit 5 outputs the test force as a test force signal to the hardness calculation unit 20. This is because the test force is used as a parameter for calculating the hardness. The test force signal here refers to, for example, a voltage signal when supplying a drive current to the drive coil.

  As shown in FIG. 2, the temperature control unit 10 includes an amplifier 11 that amplifies the temperature signal output from the temperature sensor 7, an A / D converter 12 that A / D converts the amplified temperature signal, and various calculations. It comprises a CPU 13 that performs processing, a RAM 14 that includes a work area and a storage area for various processes, a ROM 15 that stores various programs and data related to temperature control, and the like. A heater 6, a temperature sensor 7, an operation unit 8, and the like are connected to the temperature control unit 10.

The CPU 13 expands a program designated from various programs stored in the ROM 15 in the work area of the RAM 14 and executes various processes according to the designated program.
Specifically, the CPU 13 functions as a temperature control unit that controls the temperature of the sample stage 2 by controlling the heater 6 based on the temperature detected by the temperature sensor 7. For example, a detected temperature of the temperature sensor 7 is input, and a drive circuit (not shown) in the heater 6 is supplied with a voltage from a power source (not shown) at a predetermined cycle based on the relationship between the detected temperature and a preset temperature set in advance. ) And PID control of the heater 6 on / off.

  The displacement meter 9 measures the indentation depth of the indenter 3 with respect to the sample S when a predetermined test force set in the load loading mechanism unit 5 is loaded by operating the operation unit 8. The displacement meter 9 uses, for example, a capacitance type displacement meter that detects the indentation depth of the indenter 3 based on the capacitance difference.

  As shown in FIG. 2, the hardness calculation unit 20 is connected to the load load mechanism unit 5 and the displacement meter 9. The hardness calculation unit 20 includes an amplifier 21 a that amplifies the test force signal output from the load load mechanism unit 5, an A / D converter 22 a that A / D converts the amplified test force signal, and a displacement meter 9. An amplifier 21b that amplifies the displacement signal output from the A, a A / D converter 22b that A / D converts the amplified displacement signal, a CPU 23 that performs various arithmetic processes, and a work area and a storage area for various processes The RAM 24 includes a ROM 25 that stores various programs, data, and the like related to the calculation of the size of the indentation formed and the hardness of the sample S.

The CPU 23 develops a program designated from various programs stored in the ROM 25 in the work area of the RAM 24 and executes various processes according to the designated program.
Specifically, the CPU 23 calculates the size of the indentation based on the displacement signal (indentation depth) of the indenter 3 output from the displacement meter 9, and then calculates the size of the indentation and the load load mechanism unit 5. The material characteristics such as hardness of the sample S are evaluated on the basis of the test force signal output from.

As shown in FIG. 1, the temperature sensor 7 is installed in the vicinity of the sample S. Since the temperature sensor 7 detects the temperature in the vicinity of the sample S, the detected temperature is regarded as the actual sample temperature. .
The operation unit 8 includes, for example, a keyboard and a mouse, and is used to input or select numerical data such as a set temperature of the heater 6 and a command related to material property evaluation.

  Next, temperature control in the hardness test as the material property evaluation of the material property evaluation apparatus 1 having the above configuration will be described. As a premise for entering this temperature control, as shown in FIG. 1, it is assumed that the sample S is placed on the sample stage 2 of the material property evaluation apparatus 1 and the set temperature is set. For example, when the set temperature is set to 300 ° C., the hardness when the sample S is 300 ° C. is measured.

  In the temperature control, first, the CPU 13 controls the heater 6 based on the temperature detected by the temperature sensor 7 to control the temperature of the sample stage 2. Specifically, the temperature near the sample S on the sample stage 2 is detected by the temperature sensor 7, and the detected temperature is input to the temperature control unit 10 as a temperature signal. This temperature signal is amplified by the amplifier 11 in the temperature control unit 10 and then A / D converted by the A / D converter 12. The amplified temperature signal is input to the CPU 13. Next, based on the relationship between the temperature signal and the set temperature, the CPU 13 outputs a heater application voltage with a predetermined period from the power source, and performs on-off control of the heater 6 by PID.

  Next, when the operation unit 8 of the material property evaluation apparatus 1 is operated with the temperature controlled to the set temperature, the load load mechanism unit 5 applies a predetermined drive current to the drive coil (not shown) based on the operation input. To generate driving force. With this driving force, the indenter shaft 4 is pressed in the axial direction and moved to form a recess on the surface of the sample S, and the hardness of the sample S is measured based on the recess.

More specifically, for example, a test force signal output from the load / load mechanism unit 5 at the time of formation of the recess is amplified by the amplifier 21a of the hardness calculation unit 20, and then A / D converted by the A / D converter 22a. The indentation depth of the indenter 3 when the depression is formed is measured by the displacement meter 9 and the displacement signal output from the displacement meter 9 is amplified by the amplifier 21 b of the hardness calculation unit 20. Thereafter, it is A / D converted by the A / D converter 22 b and input to the CPU 23.
Then, the CPU 23 calculates the size of the recess formed in the sample S by the indenter 3 based on the input displacement signal, and then, based on the calculated size of the recess and the input test force signal, Calculate the hardness.

  According to the material property evaluation apparatus 1 according to the present invention described above, since the sample stage 2 is made of ceramics having a small thermal expansion coefficient, the thermal expansion of the sample stage 2 can be suppressed. Accordingly, it is possible to reduce the measurement error due to the thermal expansion of the sample stage 2 during the operation of the indenter and perform a more accurate hardness test.

Although the temperature control is performed by the CPU 13, a configuration including a control circuit or the like may be used.
Moreover, in the said embodiment, although the hardness calculation part 20 is provided and the hardness test of the sample S is performed as material characteristic evaluation, it is not limited to this. For example, the elastic modulus of the sample S may be measured by storing a program for calculating the elastic modulus of the sample S in the ROM 25 and measuring the indentation depth during the indentation of the indenter 3 with respect to the sample S over time. Is possible. In addition, physical property values such as adhesion property surface physical properties and wear resistance properties of the sample S can also be evaluated.

It is a schematic diagram of the structure of the material characteristic evaluation apparatus which concerns on this invention. It is a block diagram of the temperature control system of the material characteristic evaluation apparatus of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Material characteristic evaluation apparatus 2 Sample stand 3 Indenter 6 Heater (heating part)
7 Temperature sensor 9 Displacement meter (Indentation depth measuring means)
13 CPU (temperature control means)

Claims (3)

A material property evaluation apparatus for forming a recess by pressing an indenter on a sample surface and evaluating a predetermined material property of the sample based on the recess,
A sample stage on which the sample is placed;
A heating unit for heating the sample stage;
A temperature sensor for detecting the temperature in the vicinity of the sample on the sample stage;
Temperature control means for controlling the temperature of the sample stage by controlling the heating unit based on the temperature detected by the temperature sensor;
With
2. The material property evaluation apparatus according to claim 1, wherein the sample stage is made of ceramics.   2. The material property evaluation apparatus according to claim 1, further comprising an indentation depth measuring means for measuring an indentation depth when the indenter is formed.   3. The material property evaluation apparatus according to claim 1, wherein the ceramic material is boron nitride.

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