| Summary: | 碩士 === 國立臺灣大學 === 材料科學與工程學研究所 === 92 === Abstract
The low CTE alloys, such as Fe-36%Ni and Fe-29%Ni-17%Co, was usually made by melting and casting. These parts need secondary machining and lead to higher cost. Since the MIM (Metal Injection Molding) process is very well developed, it is very likely that the produce the low CTE alloys with complex shapes.
MIM''ed Kovar made from prealloyed powders and mixed elemental powders in this study. The mixed elemental powder could attain higher density (95~96%). Both of prealloyed powders and mixed elemental powder produce uniform alloy distributions. The carbon pollution can be kept low and does not affect the CTE. The CTEs of Kovar are 4.8 mm/m℃ (for mixed powders) and 4.74 mm/m℃ (for prealloyed powders). The CTE of Invar is 1.49 mm/m℃ (for the mixed powders). They are all close to those by melting and casting.
To find out the adequate range for the alloy composition, were changed and it was found that the {Fe(54%)-Ni(28~33%)-Co(13~17%)}.
To have good metal to glass sealing, it need to pre-oxidize the alloy. After sealing at 1115 for 15 mins, a shear strength of 160 MPa was obtained. The sealing does not fail the temperature cycling until 300 cycles are reached.
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