| Project/Area Number |
05650629
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
Inorganic materials/Physical properties
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| Research Institution | Tokyo Institute of Technology |
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Principal Investigator |
SHINOZAKI Kazuo Tokyo Institute of Technology Fuculty of Engineering, Associate Professor, 工学部, 助教授 (00196388)
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| Co-Investigator(Kenkyū-buntansha) |
SAKURAI Osamu Tokyo Institute of Technology Fuculty of Engineering, Technician, 工学部, 教務職員 (20108195)
FUNAKUBO Hiroshi Tokyo Institute of Technology Fuculty of Engineering, Research Associate, 工学部, 助手 (90219080)
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| Project Period (FY) |
1993 – 1994
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| Project Status |
Completed (Fiscal Year 1994)
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| Budget Amount *help |
¥2,500,000 (Direct Cost: ¥2,500,000)
Fiscal Year 1994: ¥400,000 (Direct Cost: ¥400,000)
Fiscal Year 1993: ¥2,100,000 (Direct Cost: ¥2,100,000)
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| Keywords | Aluminum Nitride / AlN / Grain Boundary Phases / Y_2O_3-Al_2O_3 / Liquid Phase Formation / Liquid Phase Sintering / High Temperature DTA |
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| Research Abstract |
The liquid phase formation in the system AlN-Y_2O_3-Al_2O_3 and the sintering mechanism in Y_2O_3 doped AlN system were investigated using self-made high-temperature DTA and quenching method. We prove the AlN itself reacts with grain boundary phases to form liquid phase at high temperature using the high-temperature DTA.
High-temperature DTA applicable upto 2000ﾟC for non-oxygen atmosphere was made using the DTA unit that composed BN cell and Re20%W/Re40%W thermocouple. The DTA cell was constructed for reducing the leak current and carbon vapor. The D.C.power source was used for reducing the noise.
Y_4Al_2O_9-AlN,Y_3Al_5O_<12>-AlN,and the eutectic composition between Y_3Al_5O_<12> and Al_2O_3 and AlN systems were used for detecting the liquid phase formation temperature by means of the DTA.Phase chemistry for the samples after DTA measurement revealed no compounds between AlN and Y_2O_3-Al_2O_3 system. The liquid phase formation temperature decreased significantly (80 to 230ﾟC) by the addition of AlN to Y_2O_3-Al_2O_3 composition. The lowest temperature of the liquid phase formation in this experiment was 1690ﾟC.
Lattice parameter of Y_4A_<12>O_9 changed slightly in the sample Y_4Al_2O_9-AlN system quenched at above liquid phase formation temperature. EPMA shows, however, no direct observation of nitrogen dissolution to Y_4Al_2O_9. This means the phase diagram of the system Y_2O_3-Al_2O_3-AlN is eutectic type. Partial phase diagram of the system Y_3Al_5O_<12>-AlN was proposed using DTA and quenchying results.
The liquid phase sintering of the Y_2O_3 added AlN system proceeds through the large amount of liqauid phase made of Y_2O_3 additive, impurity oxygen and AlN itself. During cooling liquid phase decomposes into Y-Al-O and AlN,oxygen remains in the Y-Al-O phases and decomposed AlN is purified. This produces the high thermal conductive AlN.
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