• 제목/요약/키워드: $Si_3N_4$ tool

검색결과 62건 처리시간 0.021초

Cutting Performance of Si$_3$N$_4$ Based SiC Ceramic Cutting Tools

  • Kwon, Won-Tae;Kim, Young-Wook
    • Journal of Mechanical Science and Technology
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    • 제18권3호
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    • pp.388-394
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    • 2004
  • Composites of Si$_3$N$_4$-SiC containing up to 30 wt% of dispersed SiC particles were fabricated via hot-pressing with an oxynitride glass. To determine the effect of sintering time and SiC content on the mechanical properties and the cutting performance, the composites with fixed 8hr-sintering time and 20 wt% SiC content were fabricated and tested. Fracture toughness of the composites increased with increasing sintering time, while the hardness increased as the SiC content increased up to 20 wt%. The hardness of the composites was relatively independent of the grain size and the sintered density. For machining heat-treated AISI4140, the insert with 20 wt% SiC sintered for 8hr showed the longest tool life while the insert with 20 wt% SiC sintered for 12hr showed the longest tool life for machining gray cast iron. An effort was made to relate the mechanical properties, such as hardness, fracture toughness and wear resistance coefficient with the tool life. However, no apparent relationship was found between them. It may be stated that tool life is affected by not only the mechanical properties but also other properties such as surface roughness, density, grian size and the number of the inherent defects in the inserts.

절삭 공구용 세라믹의 소결조직에 따른 파괴인성과 경도의 평가 (Effect of Microstructure on Evaluation of Fracture Toughness and Hardness of Cutting Tool Ceramics)

  • 안동길;윤명진
    • 한국생산제조학회지
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    • 제9권6호
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    • pp.170-177
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    • 2000
  • Dense $Al_2$O$_3$-30%TiC and Si$_3$N$_4$ ceramic tool materials with various grain size were produced by sintering-HIP treatment and by gas-pressure sintering. The fracture toughness was measured by indentation fracture and indentation strength method for both ceramics with various grain size. The effect of the grain size on the fracture toughness was evaluated, and the correlation between fracture toughness and mechanical properties such as hardness, Young\`s modulus and flexural strength of these ceramic were also investigated. The highest fracture toughness of around 6.7 MPa.m(sup)1/2 was obtained in Si$_3$N$_4$ ceramics with grain size of 1.58${\mu}{\textrm}{m}$. With a larger grain size of $Al_2$O$_3$-30%TiC and Si$_3$N$_4$ ceramics, the fracture toughness was generally increased. The increased fracture toughness of these ceramic also improved the flexural strength although the hardness decreased considerably. Similar results were obtained in grain size and mechanical properties on both $Al_2$O$_3$-30%TiC and Si$_3$N$_4$ ceramic tool materials.

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하이브리드 코팅에 의한 고경도 소재용 Ti-Al-Si-N코팅 엔드밀의 절삭성능평가 (Cutting Performance of Ti-Al-Si-N Coated Endmill for High-Hardened materials by Hybrid Coating System)

  • 김경중;강명창;이득우;김정석;김광호
    • 한국공작기계학회:학술대회논문집
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    • 한국공작기계학회 2003년도 추계학술대회
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    • pp.89-94
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    • 2003
  • Hard coatings are known to improve the performance of cutting tools in aggressive machining applications, such as high speed machining. New superhard Ti-Al-Si-W films, characterized by a nanocomposite nano-sized (Ti,Al,Si)N crystallites embedded in amorphous $Si_3 N_4$ matrix, could be successfully synthesized on WC-Co substrates by a hybrid coating system of arc ion plating(AIP) and sputtering method. The hardness of Ti-Al-Si-N film increased with incorporation of Si, and had the maximum value ~50 GPa at the Si content of 9 at.%, respectively. And the X-ray diffraction patterns of Ti-Al-Si-N films with various Si content is investigated. In this study, Ti-Al-Si-N coatings were applied to end-mill tools made of WC-Co material by a hybrid coating system. Cutting tests fir the high-hardened material (STD11,$H_R$)C62 and their performances in high speed cutting conditions were studied. Also, the tool wear and tool lift of Ti-Al-Si-N with various si(6, 9, 19) contents were measured.

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HfN/Si$_3$N$_4$와 NbN/$Si_3N_4$다층박막의 기계적 특성 (Mechanical Properties of HfN/Si$_3$N$_4$and NbN/$Si_3N_4$Multilayer Coatings)

  • 정진중;황선근;이종무
    • 한국재료학회지
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    • 제11권3호
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    • pp.236-242
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    • 2001
  • 고속도 공구강 기판에 반응성 스퍼터링법으로 증착된 HfN/Si$_3$N$_4$와 NbN/Si$_3$N$_4$다층박막의 기계적인 성질들을 막 증착 조건에 따라 평가하였다. HfN/Si$_3$N$_4$와 NbN/Si$_3$N$_4$ 다층박막의 강도는 $N_2$/Ar비가 0.4일 때가지 증가하다가 유량비가 증가함에 따라 더 이상 증가하지 않았다. 두 다층박막의 강도는 낮은 온도에서의 열처리에 의해서는 거의 변화가 업지만 80$0^{\circ}C$ 정도의 고온에서는 열처리에 의한 산화로 인하여 감소하였다. 낮은 온도에서의 열처리는 밀착성을 향상시키는 반면 고온에서의 열처리는 강도의 감소 이외에 밀착성이 감소하므로 바람직하지 못하다.

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Coated $Si_3N_4$-TiC Ceramic 공구의 마모 특성 (Wear Characteristics of Coated $Si_3N_4$-TiC Ceramic Tool)

  • 김동원;권오관;이준근;천성순
    • Tribology and Lubricants
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    • 제4권2호
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    • pp.44-51
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    • 1988
  • Titanium carbide(TiC), Titanium nitride(TiN), and Titanium carbonnitride(Ti(C,N)) films were deposited on $Si_3N_4$-TiC composite cutting tools by chemical vapor deposition(CVD) using $TiCl_4-CH_4-H_2$, $TiCl_4-N_2-H_2$, and $TiCl_4-CH_4-N_2-H_2$ gas mixtures, respectively. The experimental results indicate that TiC coatings compared with TiN coatings on $Si_3N_4$ -TiC ceramic have an improved microstructural property, good thermal shock resistance, and good interfacial bonding. However TiN coatings compared with TiC coatings have a low friction coefficient with steel and good chemical stability. It is found by cutting test that coated insert compared with $Si_3N_4$-TiC ceramic have a superior flank and crater wear resistance. And multilayer coating compared with monolayer coating shows a improved wear resistance.

SiO$_2$/Si$_3$N$_4$ 이중 박막의 C-V 특성 (Capacitance-Voltage Characteristics in the Double Layers of SiO$_2$/Si$_3$N$_4$)

  • Hong, Nung-Pyo;Hong, Jin-Woong
    • 대한전기학회논문지:전기물성ㆍ응용부문C
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    • 제52권10호
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    • pp.464-468
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    • 2003
  • The double layers of $SiO_2$/$Si_3$$N_4$ have superior charge storage stability than a single layer of $SiO_2$. Many researchers are very interested in the charge storage mechanism of $SiO_2$/$Si_3$$N_4$ [1,2]. In this paper, the electrical characteristics of thermal oxide and atmospheric pressure chemical vapor deposition (APCVD) of $Si_4$$N_4$ have been investigated and explained using high frequency capacitance-voltage measurements. Additionally, this paper will describe capacitance-voltage characteristics for double layers of $SiO_2$/$Si_4$$N_4$ by "Athena", a semiconductor device simulation tool created by Silvaco, Inc.vaco, Inc.

SiC계 세라믹 절삭공구의 절삭특성 평가 Part 1: SiC계 절삭공구의 미세구조와 기계적 특성 (Cutting Characteristics of SiC-based Ceramic Cutting Tools Part 1: Microstructure and Mechanical Properties of SiC-based Ceramic Cutting Tools)

  • 박준석;김경재;심완희;권원태;김영욱
    • 한국정밀공학회지
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    • 제18권9호
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    • pp.82-88
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    • 2001
  • In order to fulfil the requirements of the various performance profiles of ceramic cutting tools, six different SiC-based ceramics have been fabricated by hot-pressing (SiC--${Si}_3 {N}_4$composites) or by hot-pressing and subsequent annealing (monolithic SiC and SiC-TiC composites). Correlation between the annealing time and the corresponding microstructure and the mechanical properties of resulting ceramics have been investigated. The grain size of both ${Si}_3 {N}_4$and SiC in SiC-${Si}_3 {N}_4$composites increased with the annealing time. Monolithic SiC has the highest hardness, SiC-TiC composite the highest toughness, and the SiC-${Si}_3 {N}_4$composite the highest strength among the ceramics investigated. The hardness of SiC-${Si}_3 {N}_4$composites was relatively independent of the grain size, but dependent on the sintered density. The cutting performance of the newly developed SiC-based ceramic cutting tools will be described in Part 2 of this paper.

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$Si_3N_4$-TiC ceamic 공구에 화학증착된 TiC, TiN 및 Ti(C, N)에 관한 연구 (A study on the chemically vapor deposited TiC, TiN, and Ti(C, N) on $Si_3N_4$-TiC ceramic tools)

  • 김동원;김시범;이준근;천성순
    • 한국윤활학회:학술대회논문집
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    • 한국윤활학회 1988년도 제7회 학술강연회초록집
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    • pp.39-42
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    • 1988
  • 요업체 절삭공구(ceramic tool)는 공구강이나 초경제품에 비해 고속 절삭 작업이 가능하며 생산성을 높일 수 있기 때문에 최근 주목을 받고 있다. 본 실험에서 모재(substrate)로 사용된 $Si_3N_4$-TiC ceramic은 요업체 공구중에서 파괴인성이 우수하며, 주철이나 초합금을 절삭할 때 우수한 성능을 나타낸다. 그러나 요업체 절삭공구중에서 경도가 낮은 편에 속하며, Fe,Mn,O와 $Si_3N_4$가 화학적 반응을 일으켜서, steel을 절삭할 때 상면 마모(crater wear)가 심하게 발생하기 때문에 우수한 성능을 나타내지 못하고 있는 실정이다. 따라서 이러한 단점을 보완하기 위해 공구의 표면에 보호피막(protective coating)을 입히는 것은 필수적이다. 본 연구에서는 반응변수들이 TiC 및 TiN 증착층의 증착속도, 미세구조, 화학적 조성 및 증착층과 substrate 사이의 interface를 조사하여 각 증착층의 최적증착조건을 규명하고자 한다.

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Characteristics of Si3N4 Laser Assisted Machining according to the Laser Power and Feed Rate

  • Kim, Jong-Do;Lee, Su-Jin;Suh, Jeong
    • Journal of Advanced Marine Engineering and Technology
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    • 제34권7호
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    • pp.963-970
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    • 2010
  • This study makes an estimate of the laser-assisted machining (LAM) of an economically viable process for manufacturing precision silicon nitride ceramic parts using a high-power diode laser (HPDL). The surface is locally heated by an intense laser source prior to material removal, and the resulting softening and damage of the workpiece surface simplify the machining of the ceramics. The most important advantage of LAM is its ability to produce much better workpiece surface quality compared to conventional machining. Also important are its larger material removal rates and longer tool life. The cutting force and surface temperature were measured on-line using a pyrometer and a dynamometer, respectively. Tool wear, chips and the surface of the workpiece were measured using optical microscopy, and the surface and fractured cross-section of $Si_3N_4$ were measured by SEM. During the LAM process, the cutting force and tool wear were reduced and oxidation of the machined surface was increased according to the increase in the laser power. Moreover, the more the feed rate increased, the more the cutting force and tool wear increased.

Effect of Cutting Tool Materials on Surface Roughness and Cutting Forces in Machining of $Al-Si_3N_4$ Composite Produced by Powder Metallurgy

  • Ozcatalbas, Yusuf;Bahceci, Ersin;Turker, Mehmet
    • 한국분말야금학회:학술대회논문집
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    • 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part2
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    • pp.1052-1053
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    • 2006
  • Aluminum-based composites reinforced with various amounts of $\alpha-Si_3N_4$ were produced by powder metallurgy (P/M). The machinability properties of $MMC_s$ were determined by means of cutting forces and surface roughness. Machining tests were carried out by using PCD and K10 tools. Increasing of $Si_3N_4$ volume fraction in the matrix resulted in a decrease of the surface roughness and turning forces. PCD cutting tools showed better cutting performance than K10 tools.

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