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Development of Measurement Techniques of Mechanical Properties in Microscopic Area

Hardness and Strength of Diamond Like Carbon Films
An ultramicro indentation hardness tester was installed in the specimen chamber of the scanning electron microscope which enabled in-situ observation of indentation process and immediate measurement of size of indentations after unloading. Diamond films prepared by chemical vapor plasma deposition process showed tendency to increase in ultra microhardness in decreasing methane gas concentration. Diamond films processed under condition of 0.1 % methane gas concentration possessed extreme high hardness value of 9400 in unit of Vickers hardness, which was comparable to the bulk natural diamonds. We are also planning a strength measurement of diamond films.
Hardness and Young's modulus of the diamond thin film as function of methane concentration
Elastic Moduli and Sound Velocity of Diamond Like Carbon Films
Young's modulus of diamond films were measured by resonance method in elevated temperatures. Young's modulus of diamond films increased with decreasing in methane concentration similarly as the case of ultramicro hardness. Especially, the Young's modulus of diamond films processed under condition of 0.1 % methane concentration became the value comparable to the bulk natural diamonds (1000GPa). And measurements of temperature dependence of Young's modulus and velocity of surface elastic wave were carried out.
Young's modulus of the diamond thin film as a function of temperature
Measurement Technique of Strength of Fibers and Whisker crystals
Ultramicro Hardness of Ceramic Monofibers
Ultramicro indentation hardness of silicon carbide (SiC) monofibers were measured. The average hardness of SiC fibers was 2095 with a standard deviation of 500.
Bending Strength and Elastic Modulus of whisker crystals
The direct measurements of bending strength of single whiskers were carried out under in-situ measurement in the scanning electron microscope. Microfabrication technique of silicon single crystals and micromanipulation technique in the optical microscope popularly used in the field of cell biology were applied in this study. A loading device for the microbending test was developed by modifying a ultramicro indentation hardness tester in the scanning electron microscope. Size effects in the strength of several kinds of whiskers were investigated. It was demonstrated that whisker crystals showed extremely high strength.
Bending strength of whisker crystals as function of diameter

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