鎳基自熔合金水砂沖蝕特性之研究

A Study of Slurry Erosion Characteristics of Ni-based Self-fluxing Alloy

本研究應用高速火焰熔射製成鎳基自熔合金，隨後進行水砂沖蝕試驗，並選擇SUS304不銹鋼作為比較材，以探討鎳基自熔合金之抗水砂沖蝕特性。實驗結果顯示，鎳基自熔合金之抗水砂沖蝕性優於SUS304不銹鋼，尤其在低角度沖擊。兩種合金靶材之重量損失皆隨著沖擊時間與沖擊速率之增加而幾乎呈線性遞增。鎳基自熔合金為一高硬度之脆性材料，於高沖擊角度下，具有較大之沖蝕速率，而SUS304不銹鋼為延性材料，其沖蝕速率於30度沖擊角時呈現最大值。鎳基自熔合金經水砂沖蝕後之顯微組織，於低角度（15及30度）沖擊後之表面形態與SUS304不銹鋼之延性靶材差異不大，即表面形成沖擊砂粒剷犁靶材之條紋狀流線痕跡；而經高角度（60及90度）沖擊後，鎳基自熔合金則呈現其本質，主要以脆性剝落破壞形態為主。

The test specimens of Ni-based self-fluxing alloy were prepared using the high-speed flame-spraying technique. Their slurry erosion characteristics using the water/sand impingement tests have been systematically studied. SUS304 stainless steel was selected as the comparison material. Experimental results showed that the Ni-based self-fluxing alloy generally exhibits a better slurry erosion resistance than the SUS304 stainless steel, especially at lower impingement angles. The cumulative weight losses for both alloys increase almost linearly with increasing erosion time and impingement speed. The Ni-based self-fluxing alloy erodes more severely at higher impingement angles due to its hard but brittle behavior. On the contrary, the SUS304 stainless steel processes a ductile behavior and the maximum of erosion rate occurs at impingement angle around 30°. Both alloys show similar surface morphologies composed of furrows after impingement at lower angles (15°, 30°). However, the Ni-based self-fluxing alloy has an impinged surface mainly from brittle exfoliation at high impingement angles of 60° and 90°.