| Project/Area Number |
08650805
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (C)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Structural/Functional materials
|
|---|
| Research Institution | Tohoku University |
|---|
Principal Investigator |
YOSHIKAWA Noboru Graduate School of Tohoku Unoversity, Reaserch associate, 大学院・工学研究科, 助手 (70166924)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
KIKUCHI Atsushi Graduate School of Tohoku Unoversity, Professor, 大学院・工学研究科, 教授 (00005307)
|
|---|
| Project Period (FY) |
1996 – 1998
|
| Project Status |
Completed (Fiscal Year 1998)
|
| Budget Amount *help |
¥2,200,000 (Direct Cost: ¥2,200,000)
Fiscal Year 1998: ¥200,000 (Direct Cost: ¥200,000)
Fiscal Year 1997: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1996: ¥1,500,000 (Direct Cost: ¥1,500,000)
|
|---|
| Keywords | MoSi_2 / ZrO_2 / transformation toughening / chemical vapor infiltration / metal organic precursor / microstructure / MOSi_2 / 硅素モリブデン / ジルコニア / ポストアニール / 正方晶相 / 浸透距離 / CVI法 / ZrO_2添加 / MoSi_2焼結体 / 有機金属原料 / 浸透組織 / 結晶化 / 複合体層 / 析出・浸透速度 |
|---|
| Research Abstract |
This study was intended to fabricate high strength ZrO_2/MoSi_2 composites, which took advantage of transformation toughening. Chemical-Vapour-Infiltration(CVI) method was adopted for incorporation of ZrO_2 into partially sintered MoSi_2. In order to obtain fundamental knowledge for fabrication process and the microstructure of the composites, ZrO_2 were deposited with no additive oxides. Microstructures of post-annealed ZrO_2 were observed and the optimum annealing conditions for realizing transformation toughening were discussed. The following results were obtained.
1) Fine MoSi_2 grains were well-covered with CVI-ZrO_2 by using Metal-Organic(MO) precursor.
2) The infiltrated ZrO_2 were all amorphous, therefore post-annealing treatment was required. The post annealed ZrO_2 at 1073K for 3.6ks in air consisted of equi-axed grains of several 10nm in diameter. Existence of monoclinic ZrO_2 was observed and this microstructure suggests the limitation of annealing conditions.
3) Hardness increase was realized by increase of ZrO_2 into MoSi_2 and maximum hardness of 20GPa was obtained in the composites. High toughness was recognized by Vickers indentation and occurrence of transformation toughening was realized.
|
