• 作者： 洪敏雄; 李瑞榮
• 作者服務機構： 國立成功大學冶金及材料工程系
• 中文摘要： 本文的主要內容為研究硼和碳添加劑對於碳化矽 (Sic) 燒結的影響，以及此兩種添加劑在Sic 燒結過程中所擔任的角色，並探討在此情況下，sic的燒結機構。 將添加劑以不同的添加量加入 β-sic 和 α-Sic中，經過混合、造粒、壓型、預燒後，於2,000°C下燒結一小時，比較添加劑和添加量對於燒結緻密化的效果。由實驗結果得知，只加硼無法使 Sic 緻密。添加 Sic 0.3～1.0 wt%硼，再配合0.5～2.0 wt% 之碳，可得較佳的效果。於2,000°C下燒結一小時，β-Sic最高可達88.7%理論密度(T.D.)，而 α-Sic則可得89.7% T.D。 添加 1 wt% 硼和1 wt% 碳於 β-sic 和 α-Sic中，分別於1，700°C 和 1,800°C燒結，測其收縮率，獲得( L/L) 之關係，據此推論，此等添加劑的作用為在 Sic 的表面上形成第二相，sic即經由此第二相傳送而緻密。 文中並做金相、掃描式電子顯微鏡、電子顯微探針、X光繞射分析燒結體及其相變態。
• 英文摘要： The principal objectives of this paper havebeen studying the effects of the boron (B) andcarbon (C) additives on the sintering of siliconcarbide (SiC) and the mechanisms in the sin-tering of SiC with these additives. Different forms and amounts of additiveswere added in β-SiC and α-SiC powder res-pectively. After mixing, granulating, compres-sion, and presintering, the samples were sinteredfor 1 hr. at 1,900°C and 2,000°C respectively.Comparing the densities and shrinkage of sam-ples with different kinds and amounts of addi-tives, it was found when B was added solely,the densities of sintered SiC samples were nothigh enough (70-75% T.D.) to have expectedmechanical properties. It was concluded that0.3-1 wt% B and 0.5-2 wt% C should be addedsimultaneously to have proper density．Afterthe samples were sintered for 1 hr. at 2,000°C,the densities were (1) β-SiC added with B andC was 88.7% T. D. (2) α-SiC added with Band C was 89.7% T. D.. β-SiC and α-SiC added with 1 wt% Band 1 wt% C were sintered at 1,700°C and1,800°C to study the mechanisms of SiC sintering.Measuring the shrinkage ( L/L) for differentsintering periods (t), the relation between themwas found to be L/L t . It was proposedthat these additives acted as a second phaseand coated on the surface of SiC grains, thenSiC species transfered through this second phaseand densified during the heating. The microstructures and the β-α transform-ation were also analyzed with SEM, X-raydiffractometer and optical microscope.
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