Impact strength of the amorphous SiNxCy ceramic films by P-CVD method

Using a charge coupled plasma CVD apparatus, SiNxCy films (Si3N4-SiC, SiNx and SiCy system) are deposited from SiH4-90%Ar, NH3, C2H4 and H2 gases on a crown glass substrate. The impact absorption energy (E) or impact strength (IS) of the coated substrate was investigated. The influence of composition from Si3N4 to SiC films was tested, for example. In the case of a film thickness of 5μm, the impact absorption energy (E ) changed from 68.1mJ (IS : 2.84kJ/m2) on the Si3N4 side to 78.1mJ (IS :3.25 kJ/m2) on the SiC side. But these energies were less than 50% of that of the substrate itself (E:159.2mJ, IS: 6.63 kJ/m2). Hard film coatings reduce impact strength.departmental bulletin pape

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Fundamental study of YAG laser processing of various ceramics

In this study, YAG laser beams with energies of about 3.8 J/shot for cutting and 6.05 J/shot for welding were applied to various ceramics such as oxides, nitrides, carbides, borides and their composites. The possibility of laser processing for ceramics and the ceramics suitable for cutting and welding were investigated with one shot irradiation. As a result, the ceramics considered to be suitable for laser processing (cutting and welding) are PLS(pressureless sintering)-TiO2, HP(hot-press)-TiB2-B4C system, HP-TiN-B4C system and PLS-Si3N4. Otherwise, HP and PLS-TiB2-ZrB2 systems are considered unsuitable ceramics.departmental bulletin pape

Manufacture and property of each Ni, Ti, NiTi metal/graphene composite by ultrasonic-assisted hot-pressing method

The composites containing 0% or 15 vol% of graphene (GnP) for each matrix metal of Ni, Ti and NiTi were prepared by hot pressing method with or without assistance of ultra-sonic waves, and the mechanical and electrical properties were compared. The relative density of Ni and Ti-based metals with 0% GnP content was 96% or higher. When 15 vol% GnP was included, it decreased to about 84-94%. The relative density of the NiTi with 0% GnP content increased from 90.6% to 98.2% by applying ultrasonics. However, when GnP was included, it decreased to 91.1-92.4%. The mechanical properties showed proportional to the relative density. The electrical conductivities of pure Ni, Ti, and NiTi metals were 9.09, 1.78 and 1.19 MS/m, respectively. The electrical conductivity of composite with 15vol% of GnP decreased, particularly for Ni-based and Ti-based materials, which decreased to 22-53%.departmental bulletin pape

Adhesive strength of the amorphous SiNxCy ceramic films by P-CVD method

Using a plasma CVD apparatus, SiNxCy films (Si3N4-SiC, SiNx, SiCy) are prepared from SiH4-90%Ar, NH3, C2H4 and H2 gases on a crown glass substrate. Adhesive strength is evaluated using critical peel load (Lc) and critical peel shear stress (σcs) as measured with the scratch test. The effects of the compositional change from Si3N4 to SiC films are investigated. When the film thickness is 1 μm, the composition dependence is large, and Lc varies greatly from 19.5N to 44.3N, and σcs values are 1.0 to 1.53GPa. On the other hand, when film thickness is 5 μm, Lc values are 17.0 to 29.5N, and σcs values are 0.9 to 1.23GPa. In addition, the film thickness and surface roughness of substrate have a large effects on the adhesive strength.departmental bulletin pape

Categories of Similes Used as Predicates

This paper categorizes predicative similes (predicate-type similes) based on actual examples. Previous research often assumes that the typical form of a simile is "A ha B no y?da," which uses the terminal form of the auxiliary verb "y?da." However, in practice, complex predicate forms such as "y? ni mieru" (appears like) connecting to formal verbs, or "y? na mono da" (is like something) connecting to formal nouns, are also used. In actual usage, adverbial modifying similes (e.g., "A ha B no y? ni C") are more common, and predicative similes are relatively rare. Nevertheless, predicative similes are easier to consider as model cases. Therefore, defining the range of forms that predicative similes can take is valuable as preliminary preparation for theoretical considerations of how similes are formed and what expressive value they hold.departmental bulletin pape

Manufacture and mechanical properties of sintered composite of VGCF-contained TiB2, SiC, Si3N4 ceramics by hot pressing method

TiB2, SiC and Si3N4 composite ceramics containing 0 or 3.23mass%VGCF (vapor grown carbon nano-fiber) were prepared by hot-press sintering method. The distribution of VGCF and mechanical and electrical properties were compared. By addition of VGCF, the relative density improved from 93.3 to 99.8% for TiB2, from 96.9 to 98.3% for SiC, and from 96.5 to 99.4% for Si3N4. In the TiB2 system, VGCF were not found in the SEM structure. In the SiC system, a large number of VGCFs were observed at the grain boundaries of SiC, and the VGCFs were uniformly dispersed. Mechanical properties such as three-point bending strength and fracture toughness were improved by approximately 1.6 times. The electrical conductivity was improved about 350 times in the case of SiC by the addition of VGCF.departmental bulletin pape

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