• 대한치과기공학회지
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• 제14권1호
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• pp.119-132
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• 1992

This paper aims to investigate the effect of B and Si upon the mechanical properties, microstructure and corrosion resistance of Co-Cr base alloy. Ten groups of alloy ingot ingot with various contents of B and Si were remelted by high frequency electrical induction furnace and cast into tensile specimen of ADA Specification No. 14 Tensile and hardness test were carried out by Amsler and Rockwell hardness tester(R-30N), respectively. The microstructures of specimen were observed by SEM. The results obtained are summarized as follows : 1. As B content is increased, tensile strength, yield strength and Rockwell hardness number(R-30N) are also increased significantly, while the elongation is decreased significantly. 2. As Si contect os increased, no significant chang in tensile strength is noticed, yield strength is slightly decreased, but Rockwell hardness number(R-30N) is moderately in creased, Elongation marks maxium value with 1% Si content while with more than 1% Si it is decreased. 3. As B content is increased corrosion resistance is decreased and is at best with 1.5% B content. Corrosion resistance is increased with the increase of Si content and the alloys with Si over 3.0% showed corrosion resistance. 4. As B content increased, precipitates are increased in number at grain boundaries. The grain size tends to become coarse with the increase of Si content. 5. Co rich-Cr alloy is present through matrix whereas at the grain boundaries Cr base precipitates are primarily formed.

• Journal of Welding and Joining
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• 제29권5호
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• pp.99-105
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• 2011

In this study, effect of Si content on nugget diameter in electric resistance spot welded dual-phase(DP) steel was investigated. The cold rolled DP steels with different Si content (0.5, 1.0, 1.5, 2.0 wt.%) were used and thickness of those sheet was 1.2mm. With increasing Si content, nugget diameter was increased at the same welding current. This is attributed to increase of heat input result from high resistivity. Also, nugget diameter was increased with an increase in Si content for the same heat input. For this reason, the melting point of DP steel is lowered with an increase in the Si content. And solid DP steel can easily be transformed to a liquid phase because the low melting point. Finally, a prediction formula for the nugget diameter(N.D.) could be obtained in terms of heat input(Q) and melting point(M.P) as follows: N.D.(mm) = 0.11Q(J) - 0.0031 M.P.($^{\circ}C$) + 0.32.

• 소성∙가공
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• 제13권6호
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• pp.522-527
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• 2004

Permalloys were successfully fabricated by melt drag casting in the present study, and their microstructure and consequent magnetic properties have been investigated as a function of Si content. In order to understand the relationship between magnetic properties and Si content, microstructure and texture were observed and phase analysis were performed by TEM. The effective permeability went through a maximum value at $2\%$ Si and then decreased with increasing Si content. Increasing Si content enlarged grain size, which resulted in improvement of permeability. However, over-added Si caused the formation of $Ni_3Fe$ order phase so that $5\%$ Si added permalloys had the smallest permeability.

• Journal of Welding and Joining
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• 제17권3호
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• pp.36-43
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• 1999

The effect of Si content in welding wires on spattering characteristics and droplet transfer phenomena was studied. In MAG welding using 80% Ar-20% $CO_2$ shielding gas, spattering characteristics and droplet transfer phenomena were varied with Si content of wire. With increasing Si content, the spattering ratio and the ratio of large size spatter $(d\geq1.0mm)$ were increased. The increase of Si content in molten metal made surface tension increase due to reduction of oxygen content, which resulted from deoxidizing action of silicon. The increase of surface tension resulted in unstable transfer phenomena and arc instability in both short circuit and spray region. With changing Si content of wire, spattering characteristics and droplet transfer phenomena was directly influenced by the variation of surface tension, compared with the effect of arc stability.

• 한국표면공학회지
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• 제47권4호
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• pp.174-180
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• 2014

In this study, TiAlSiN coatings have been successfully synthesized on stainless steel and tungsten carbide substrate by a hybrid coating method employing a cathodic arc and a magnetron sputtering source. TiAl and Si target were vaporized with the cathodic arc source and the magnetron sputtering source, respectively. Process gas was the mixture of nitrogen and argon gas. With the increase of Si content, the crystallinity and the grain size of TiAlSiN film was decreased. At the Si content of more than 8 at.%, grain size of TiAlSiN was saturated at around 2 nm. The hardness value of the TiAlSiN film increased with incorporation of Si, and had the maximum value of ~ 3,233 Hv at the Si content of 9.2 at.%. The oxidation resistance of TiAlSiN film was enhanced with the increase of Si content.

• 한국세라믹학회지
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• 제30권2호
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• pp.85-92
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• 1993

Oxynitride glasses in Na-Ca-Si-O-N system were prepared by melting at 135$0^{\circ}C$ for 2 hours in N2 gas. The effects of Si/Na mole ratio and the various Si3N4 contents were investigated. Stable oxynitride glasses can be obtained up to 9wt.% Si3N4 content in case the Si/Na mole ratio was 2.12 and 1.62, but $\beta$-Si3N4 was precipitated at 9wt.% Si3N4 content in case the Si/Na mole rtio was 1.12. Density (p), chemical durability, hardness (Hv), and fracture toughness (KIC) increased with increasing Si3N4 content. In cae the Si/Na mole ratio was 1.12, the increment of properties was remarkable but hardness and fracture toughness did not increase no longer owing to precipitation of $\beta$-Si3N4.

• 한국표면공학회지
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• 제36권2호
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• pp.122-127
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• 2003

Ti - Si - N hard films were deposited on SKD11 steel substrates by a hybrid deposition system, where TiN was deposited by AIP method while Si was incorporated by sputtering one. The microstructure of Ti-Si-N films was revealed to be a composite of TiN crystallites and amorphous Si3N4 by instrumental analyses. The highest hardness value of about 45 Gpa was obtained at the Si content of around 7.7 at.%. With increase of Si content, the size of TiN crystallites was reduced and their distribution was changed from aligned to randomly orientated states. Surface roughness of Ti-Si-N film also decreased with increase of Si content.

• 한국전기전자재료학회논문지
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• 제21권1호
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• pp.44-48
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• 2008

Hole mobility characteristics of two representative biaxially strained SiGe/Si structures with high Ge contents are studied, They are single channel ($Si/Si_{1-x}Ge_x/Si$ substrate) and dual channel ($Si/Si_{1-y}Ge_y/Si_{1-x}Ge_x/Si$ substrate), where the former consists of a relaxed SiGe buffer layer with 60 % Ge content and a tensile-strained Si layer on top, and for the latter, a compressively strained SiGe layer is inserted between two layers, Owing to the hole mobility performance between a relaxed SiGe film and a compressive-strained SiGe film in the single channel and the dual channel, the hole mobility behaviors of two structures with respect to the Si cap layer thickness shows the opposite trend, Hole mobility increases with thicker Si cap layer for single channel structure, whereas it decreases with thicker Si cap layer for dual channel. This hole mobility characteristics could be easily explained by a simple capacitance model.

• 한국진공학회지
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• 제10권3호
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• pp.321-327
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• 2001

Radio frequency magnetron sputtering방법으로 타켈의 Ti/si 조성과 $N_2$ 유량을 변화시켜 증착한 다양한 조성비의 Ti-Si-N 박막의 비저항 변화와 확산방지능력을 조사하였다. 높은 Si 함량을 포함한 Ti-Si-N박막내의 Si은 주로 비정질의 $Si_3N_4$ 형태로 존재하였으며 $N_2$의 양이 증가함에 따라 비저항도 증가하였다. 반면, 낮은 Si 함량을 포함한 Ti-Si-N박막은 낮은 $N_2$ 유량에서도 결정질의 TiN이 형성되었고 낮은 비저항을 나타내었다. 또한, 박막내의 N의 양이 증가함에 따라, 높은 박막의 밀도와 압축응력을 갖는 Ti-Si-N이 형성되었으며, 이는 박막 내의 N의 함량이 확산방지능력에 영향을 미치는 가장 중요한 요소 중 하나로 판단된다. 결과적으로, 29~49 at.%, Ti, 6~20 at.% Si, 45~55 at.% N 범위의 조성을 갖는 Ti-Si-N박막이 우수한 확산 억제 능력을 보유하면서 또한 낮은 비저항 특성을 나타내는데 적합한 조성 범위로 나타났다.

• 한국표면공학회지
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• 제36권2호
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• pp.116-121
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• 2003

Ti-Si-N coating layers were deposited onto WC-Co substrates by a hybrid system of arc ion plating (AIP) and sputtering techniques. The tribological behaviors of Ti-Si-N coating layers with various Si contents were investigated by the dry sliding wear experiments, which were conducted at three different sliding speeds, 0.1, 0.3, 0.5 m/s, against the steel and alumina balls. In the case of steel ball, the average friction coefficient slightly decreased with increasing the sliding speed regardless of Si content due to adhesive wear behavior between coating layer and steel ball. At constant sliding speed, the average friction coefficient decreased with increase of Si content. On the contrary, in the case of alumina ball, the average friction coefficient increased with increasing the sliding speed regardless of Si content, indicating that the abrasive wear behavior was more dominant when the coating layers slide against alumina ball. Through these experimental results, it was found that the tribological behaviors of Ti-Si-N coating layers were effected by factors such as Si content, sliding speed, and kinds of counterpart materials rather than the hardness of coating layer.