초록

- 열합성법에 의한 화합물합성
o연소합성법에 의한 합성
o반응소결법에 의한 합성
- 나노결정 화합물의 물성평가
o 기계화학적반응에 의한 나노결정 생성
o 나노결정 화합물의 열적 특성
- 광물 및 금속산화물을 이용한 복합분말의 합성
o 기계화학적 방법에 의한 합성
o 열환원법에 의한 금속화합물의 합성

Abstract ▼

Synthesis of TiC
TiC was synthesized using the SHS method. Two types of raw materials were used in the experiment. The first was the stoichiometric mixture of titanium and graphite(18 w/o) powders, and the second was a mixture of $TiO_{2}$, grahite and Mg powders. The powders were mixe

Synthesis of TiC
TiC was synthesized using the SHS method. Two types of raw materials were used in the experiment. The first was the stoichiometric mixture of titanium and graphite(18 w/o) powders, and the second was a mixture of $TiO_{2}$, grahite and Mg powders. The powders were mixed and pressed to form cylindrical shape, which were then ignited with a incandescent tungsten filament in vacuum environment. Preliminary heating was not necessary to start the 505 reactions.
In the former case, the reaction progressed very fast at about 1650℃ . The XRD pattern of the synthesized TiC exhibited relatively low peak intensity indicating that the reaction time was not long enough for sufficient grain growth.
In the latter case, the reaction temperature was dependent on the amount of Mg added under 1600'c but was independent of the amount Mg as well as that of C above 1600℃.
Synthesis of TiAI and its Grain Size Control
The effect of the green density of the pressed specimens on the SHS reaction was found to be pronounced. The reaction temperature was essentially constant around 1230℃ from 58.8% to 66.7% of relative green density, but it increased drastically to 1430℃ as the density increased from 72.2% to 86.6%.
The synthesis product consisted of the TiAl(Llo type) matrix and a small amount of precipitated $Ti_{3}$ Al in it. This product was milled for 100hrs in argon and hydrogen atmospheres, respectively. $Ti(Al)H_{2}$ precipitation was observed at 2 atm.. of hydrogen pressure.
When the milled powder was heated, crystallization process took place in the following order: amorphous phase → TiAl(metastable hcp phase) → Llo type TiAl(stable intermetallic compound). An endothermic dehydriding reaction accompanies the process.
The TEM analysis of the milled product under 2 atm hydrogen pressure showed some amorphous phase and the crystallized $Ti(Al)H_{2}$ phase. The hydrides were uniformly distributed around 10-20nm particle size. When heat-treated, these hydrides are dissociated to form TiAl, but the dehydriding reaction tends to suppress the growth of the TiAl phase, thereby limiting its grain size under 20nm.

목차 Contents

• 표지 ...1
• 제출문 ...2
• 요약문 ...3
• SUMMARY ...7
• 목차 ...9
• 제 1 장 서 론...11
• 제 1 절 연구개발의 현황과 목적...11
• 1. 금속화합물의 합성 기술 개발...11
• 2. 본 연구의 목적...11
• 제 2 장 국내외 기술개발 현황...13
• 제 1 절 금속화합물 분말 합성법...13
• 1. 기존의 합성법...13
• 제 2 절 자전고온 합성법(SHS법)에 의한 금속화합물 합성...14
• 1. 개요...14
• 2. 이론적 고찰...15
• 가. 단열반응 온도...15
• 나. 반응속도...16
• 3. SHS반응에 영향을 미치는 주요 변수들...18
• 가. 화학 양론비 (Stoichiometric Ratio)...18
• 나. 분말의 입도(Particle Size)...18
• 다. 압분 밀도(Compact Density)...18
• 라. 압분체의 직경 (Compact Diameter)...18
• 제 3 장 연구개발 수행내용 및 결과...20
• 제 1 절 TiC 합성...20
• 1. 개요...20
• 2. 실험 방법...21
• 가. 실험...21
• (1) 시료 및 전처리...21
• (2) 합성 실험...21
• (3) 산세 및 특성 평가...21
• 3. 실험 결과 및 고찰...23
• 가. Ti-C상태도...23
• 나. 시료의 혼합 및 압분성형...23
• 다. Ti과 C의 직접반응에 의한 TiC의 합성...24
• 라. Mg를 이용한 TiO2로부터 TiC의 합성...24
• (1) 조성의 영향...24
• (2) 합성물 중의 MgO제거...27
• (3) 합성 TiC분말의 미세조직 및 입도 분포...30
• 제 2 절 TiAl 합성 및 결정립 제어...39
• 1. 개요...39
• 2. 실험 방법...41
• 가. 실험...41
• (1) 시료 및 전처리...41
• (2) 합성 실험...41
• (3) 수소(H2)중 Milling에 의한 수소화물 형성 및 상분해...41
• (4) 특성 평가...41
• 3. 실험 결과 및 고찰...42
• 가. 시료의 혼합 및 압분성형...42
• 나. SHS법에 의한 TiAl화합물의 합성...42
• (1) 압분 밀도(Green Density)의 영향...42
• 다. HDDR법 에 의한 결정립 미세화...44
• (1) Milling에 의한 수소화 처리 및 비정질화...46
• (2) 비정질상의 결정화...46
• 가) Ar가스 분위기중 Milling한 시료의 탈수소 및 결정화...46
• 나) H2가스 분위기 중 Milling한 시료의 탈수소 및 결정화...49
• (3) 입도 및 미세조직...50
• 제 3 절 결론...60
• 1. TiC 합성...60
• 2. TiAl 합성 및 결정립 제어...60
• 제 4 장 연구개발목표 달성도 및 대외기여도...61
• 제 5 장 연구개발결과의 활용계획...62
• 제 6 장 참고문헌...63