• Title/Summary/Keyword: Aluminum carbide

Search Result 75, Processing Time 0.03 seconds

Graphitization of Petroleum Cokes by Aluminum Catalyst (Aluminum 촉매에 의한 석유 Cokes의 흑연화)

  • 염희남;김경자;정윤중
    • Journal of the Korean Ceramic Society
    • /
    • v.32 no.6
    • /
    • pp.677-684
    • /
    • 1995
  • The effect of catalytic graphitization of petroleum cokes by the addition of aluminum were investigated. The degree of graphitization carbon body only fired at 230$0^{\circ}C$ was 0.5. But when the aluminum additive was added, the degree of graphitization was increased to 0.93. And Ts-effect was appeared as the catalytic effect. This effect was occurred by the formation-decomposition of aluminum carbide through the reaction of aluminum and cokes.

  • PDF

Damping Capacity of Mg-Al Casting Alloy Refined by Aluminum Carbide Particles (알루미늄 카바이드 입자로 미세화된 Mg-Al 주조합금의 진동감쇠능)

  • Jun, Joong-Hwan
    • Journal of the Korean Society for Heat Treatment
    • /
    • v.20 no.6
    • /
    • pp.293-298
    • /
    • 2007
  • Influences of aluminum carbide ($Al_4C_3$) addition on microstructure and damping capacity of Mg-3%Al casting alloy have been investigated based on experimental results of optical micrography, scanning electron microscopy with energy-dispersive spectrometry analysis and damping capacity measurement at RT. The addition of $Al_4C_3$ particles results in an efficient grain refinement. The damping capacity shows an increasing tendency with an increase in $Al_4C_3$ content. The damping value associated with $Al_4C_3$ particles is linearly dependent on the volume fraction of $Al_4C_3$ particles to the 2/3 power, $f_{2/3}$, which corresponds to the total surface area of the particles.

Friction Welding of Dissimilar Press Punch Materials and Its Evaluation by AE (이종재(SKNM50-SCM440) 금형펀치의 마찰용접과 AE품질평가)

  • 오세규;박일동;전태언;이원석;이향동
    • Proceedings of the KWS Conference
    • /
    • 1995.10a
    • /
    • pp.165-169
    • /
    • 1995
  • This paper deals with determining the proper friction welding condition and analyzing mechanical in of friction welded joints of sintered carbide tool materials (SKNM50 for the blade part of press punch) to alloy steel (SCM440 for the shank part of press punch), the alloy steel to aluminum(A6061 for the interlayer material between the blade part and the shank) and sintered carbide tool materials to aluminum. And also acoustic emission test will be carried out during fiction welding to evaluate the weld quality.

  • PDF

Exposure Assessment of Airborne Dust in Manufacturing Industries Using Silicon Carbide in Korea (우리나라 실리콘카바이드 취급사업장의 공기 중 분진 노출평가)

  • Lee, Jun Jung;Phee, Young Gyu
    • Journal of Korean Society of Occupational and Environmental Hygiene
    • /
    • v.21 no.3
    • /
    • pp.177-183
    • /
    • 2011
  • Occupational exposure to silicon carbide dust of manufacturing industries has seldom been evaluated in Korea. Accordingly, we evaluated various silicon carbide dust concentrations in the breathing zone of workers between May 2010 and July 2010. To compare silicon carbide dust concentrations, three dust samplers including the Institute of Occupational Medicine (IOM) sampler, 37mm cassette sampler, and Aluminum cyclone sampler were used. A total of 5 manufacturing industries producing abrasive and refractory materials using silicon carbide were investigated. The geometric mean concentrations were 2.04, 0.97, and $0.48mg/m^3$ in inhalable, total and respirable silicon carbide dust, respectively. The geometric mean concentrations of silicon carbide in abrasive material manufacturing industries were slightly higher than that of refractory manufacturing industries, and finishing operations were higher than that of other operations. It was found that the results of exposure assessment in airborne dust at manufacturing industries using silicon carbide in Korea showed exceeding rate to American Conference of Governmental Industrial Hygienists Threshold Limit Value ($3mg/m^3$) was 10% in respirable dust samples. Therefore, with the consideration of the close relationship between smaller dust size and the occurrence of occupational respiratory diseases, it is suggested to promulgate the new occupational exposure limit for respirable silicon carbide dust.

A STUDY ON THE SURFACE ROUGHNESS AND REFLECTIVITY AFTER POLISHING OF THE MICROFILL, HYBRID COMPOSITE RESINS (Microfill, Hybrid 복합레진 연마 후 표면조도와 광반사율에 관한 연구)

  • Moon, Anne-Jay;Kwon, Hyuk-Choon
    • Restorative Dentistry and Endodontics
    • /
    • v.19 no.2
    • /
    • pp.513-533
    • /
    • 1994
  • The smooth surface after polishing of composite resin contributes to the patient's comfort, and appearance and longevity of the restoration. This study was performed for the quantitative analysis of the effects of the various finishing and polishing instruments on the surface roughness and reflectivity of the microfill, and hybrid composite resins. Cylindrical specimens 2mm thick and 10mm in diameter of Silux Plus, Durafill VS ; Z100, Prisma TPH, Brilliant, and Herculite XR composite resin were polymerized under the matrix strip. 18 specimens for each composite resin materials were divided into 6 groups ; 5 experimental groups were abraded with # 600 sand paper to remove resin-rich layer, except control. Thereafter, using diamond bur(Mani Dia-Burs), carbide bur(E. T. carbide set 4159), rubber point(Composite polishing kit), aluminum-oxide disk(Sof-Lex disk), polishing paste(Enhance system) ; each specimen was polished to its best achievable surface according to manufacturer's directions. Final polished surfaces were evaluated for the surface roughness with profilometer(${\alpha}$-step 200, Tencor instruments, USA) and for the reflectivity with image analyser(Omniment Image Analyser, Buehler, USA). The results were as follows. 1. Polishing paste or aluminum-oxide disk finish in the microfill, and hybrid composite resins was as smooth as matrix strip finish on the surface roughness test. 2. Polishing paste or aluminum-oxide disk finish in the microfill ; polishing paste finish in the hybrid composite resins was as reflective as matrix strip finish on the refectivity test. 3. For the polishing paste, there were no significant differences between the composite resin materials on the surface roughness and refectivity tests. 4. For the aluminum-oxide disk, the best result was obtained with the microfill composite resin on the surface roughness and reflectivity test. 5. Diamond bur, carbide bur, and rubber point were inappropriate for the final polishing instruments.

  • PDF

The Effect of TMT on Mechanical Properties of Steel & Aluminum Alloy (철강(鐵鋼) 및 알루미늄재료(材料)의 기계적(機械的) 성능(性能)에 미치는 TMT(thermomechanical treatment)의 영향)

  • So, Myoung-Gi
    • Journal of Industrial Technology
    • /
    • v.1
    • /
    • pp.53-60
    • /
    • 1981
  • A study has been performed on the effect of TMT(thermomechanical treatment) on the mechanical properties of steel and aluminum alloys. Improvement of the mechanical properties on steel by HTMT is due to refinement of prior austenite grain size, martensite lath size and the distribution of fine carbide precipitates and on aluminum alloy by ITMT is due to grain size refinement, homogeneous distribution of small second phase particles and retardation of the recrystallization.

  • PDF

Effect of Aluminum Addition on Porosity and Flexural Strength of Porous Self-Bonded Silicon Carbide Ceramics (알루미늄 첨가가 다공질 Self-Bonded SiC 세라믹스의 기공률과 꺾임강도에 미치는 영향)

  • Lim, Kwang-Young;Kim, Young-Wook;Woo, Sang-Kuk;Han, In-Sub
    • Journal of the Korean Ceramic Society
    • /
    • v.46 no.5
    • /
    • pp.520-524
    • /
    • 2009
  • Porous self-bonded silicon carbide (SBSC) ceramics were fabricated at temperatures ranging from 1750 to $1850^{\circ}C$ using SiC, Si, C as starting materials and Al as an optional sintering additive. The effect of Al addition on the porosity and strength of the porous SBSC ceramics were investigated as functions of sintering temperature and Si:C ratio. The porosity increased with decreasing the Si:C ratio and increasing the sintering temperature. It was possible to fabricate SBSC ceramics with porosities ranging from 37% to 44% by adjusting the Si:C ratio and the sintering temperature. Addition of Al additive promoted densification and necking between SiC grains, resulting in improved strength. Typical flexural strengths of SBSC ceramics with and without Al addition were 44 MPa and 34MPa, respectively.

Surface Roughness Characteristics of Cemented Carbide Ground by Laminated Diamond Wheel (적층 다이아몬드 숫돌로 연삭된 초경합금의 표면거칠기 특성)

  • Kim, Kang
    • Journal of the Korean Society for Precision Engineering
    • /
    • v.20 no.8
    • /
    • pp.47-53
    • /
    • 2003
  • It was already proven experimentally that the laminated grinding wheel is superior to the general grinding wheel in the productivity of grinding. However, it can't be guaranteed when the workpiece material is cemented carbide. Because of its extreme hardness, the grinding wheels made up of super-abrasives are used for grinding it. So, to investigate the performance in extremely hard materials grinding using super-abrasive grinding wheels, the surface roughness characteristics of cemented carbide ground by the laminated diamond wheels are studied experimentally. Through this study, it is found that the similar surface roughness characteristics, those were found in the studies on the laminated aluminum oxide wheels, are still available.

Effect of Additive Composition on Mechanical Properties of Silicon Carbide Sintered with Aluminum Nitride and Erbium Oxide

  • Lee, Sung-Hee;Kim, Young-Wook
    • Journal of the Korean Ceramic Society
    • /
    • v.42 no.1
    • /
    • pp.16-21
    • /
    • 2005
  • The effect of additive composition, using AlN and $Er_{2}O_{3}$ as sintering additives, on the mechanical properties of liquid-phase-sintered, and subsequently annealed SiC ceramics was investigated. The microstructures developed were quantitatively analyzed by image analysis. The average thickness of SiC grains increased with increasing the $Er_{2}O_{3}/(AlN + Er_{2}O_{3})$ ratio in the additives whereas the aspect ratio decreased with increasing the ratio. The mechanical properties versus $Er_{2}O_{3}/(AlN + Er_{2}O_{3})$ ratio curve had a maximum; i.e., there was a small composition range at which optimum mechanical properties were realized. The best results were obtained when the ratio ranged from 0.4 to 0.6. The flexural strength and fracture toughness of the SiC ceramics were $550\~650\;MPa$ and $5.5\~6.5$ MPa${\cdot}m^{1/2}$, respectively.

Influence of Liquid-Phase Amount on the Microstructure and Phase Transformation of Liquid-phase Sintered Silicon Carbide (액상량이 탄화규소 소결체의 미세구조 및 상변태에 미치는 영향)

  • 이종국;강현희;박종곤;이은구
    • Journal of the Korean Ceramic Society
    • /
    • v.35 no.4
    • /
    • pp.413-419
    • /
    • 1998
  • ${\beta}$-silicon carbides with yttrium aluminum garnet of 2,5,10 mol% were prepared by a liquid--phase sint-ering and the microstructural evolution and phase transformation were investigated during sintering as functions of liquid-phase amount and sintering time. The rate of grain growth decreases with the addition of the amount of yttrium aluminum garnet (YAG) in the SiC starting powder however the apparent density and the aspect ratio of grains in sintered body increase. The phase transformation from ${\beta}$-SiC to ${\alpha}$-SiC were dependent on the liquid-phase amount and sintering time.

  • PDF