[(Co50Cr15Mo14C15B6)97.5Er2.5]93Fe7非晶合金在600～700℃空氣氧化之研究

Air-Oxidation Behavior of a [(Co50Cr15Mo14C15B6)97.5Er2.5]93Fe7 Bulk Metallic Glass at 600 ~ 700 ℃

本研究探討[（Co50Cr15Mo14C15B6）97.5Er2.5]93Fe7非晶合金（簡稱Co7-BMG）在600 ~ 700℃空氣的氧化行為。研究結果顯示，Co7-BMG的氧化動力學遵守拋物線律，其氧化反應速率常數（ks）隨溫度上升而增加，整體而言，非晶的氧化速率比純鈷慢約3.8個數量級，顯示Co-7BMG非晶有較佳的抗氧化性質。Co7-BMG氧化後生成CoO、Co3O4、CoMoO4及Cr2O3的氧化物為以及Co3B結晶相，其中生成Co3B相可知非晶基材經氧化後已有結晶反應，此外，比較純鈷氧化後生成CoO及Co3O4，推測生成CoMoO4與Cr2O3是非晶氧化速率降低的原因。

Air-oxidation behavior of a [(Co50Cr15Mo14C15B6)97.5Er2.5]93Fe7 bulk metallic glass (Co7- BMG)was studied over the temperature range of 600 ~ 700 ℃. The results showed that the oxidation kinetics of Co-BMG followed the parabolic-rate law, and the oxidation rate constants (ks) increased with increasing temperature. It was found that the oxidation rates of the amorphous alloy were slower than those of pure cobalt by at least 3.8 orders of magnitude, indicating a better oxidation resistance of the Co7-BMG. The scales formed on the Co7-BMG consisted of CoO, Co3O4, CoMoO4, Cr2O3 and uncorroded Co3B. The formation of Co3B indicated that the crystallization of the amorphous substrate occurred during oxidation. It was very likely that the formation of CoMoO4 and Cr2O3 was responsible for the significant reductions in oxidation rate for the Co7-BMG, as compared to the greater oxidation rates of pure Co.