磨鍍薄層對表面磁化影響之研究

Effects of tribo-coatings on surface magnetization

高振耀(Chen-Yao Kao)

指導教授 ： 張育斌

共同指導教授 ： 周煥銘

崑山科技大學/工程學院/機械工程研究所/碩士(2008年)

摘要

本研究動態量測摩擦係數及表面磁場之變化以研究磨鍍薄層對摩擦磁化的影響。除了主要以純銅與鐵配對的方式做為實驗試片之外，並追加鋁、錫、鋅、紅銅、黃銅、鉑、金、銀分別對鐵摩擦之實驗，以釐清配對材料之互熔性對磨鍍薄層及表面磁場變化之影響。
由於先前之研究已發現鐵對鐵自己配對時，滑動速率只會增加表面溫昇而消磁，並不會明顯影響磨耗機制，然而，垂直負荷卻會影響磨耗機制並導致表面磁化。因此，本實驗也以垂直負荷及線速度為實驗操作參數，根據動態量測摩擦係數及表面磁場的實驗結果，並配合磨耗表面之SEM照片觀察，研究磨鍍薄層對表面磁化之影響。
結果顯示只有在嚴重磨耗時才會出現明顯的表面磁場變化，故由表面磁場產生的瞬間即可判定材料轉移的時機。隨著垂直負荷之增加，磨鍍薄層堆疊層數越多且越厚，磁化越嚴重。隨線速度之增加，磨鍍薄層之磨鍍面積增大且磨鍍薄層之表面形貌也較平整，其產生表面磁化之摩擦距離有延後的現象並且在高速時有短暫的消磁現象。整體而言，銅對鐵的消磁現象與鐵對鐵的消磁現象是不同型態的情況，但其表面磁場飽和值一致。配對材料之互熔性與合金材料之高硬度性質會影響磨鍍薄層堆疊之表面形貌，並進而影響動態摩擦係數及表面磁場之變化。因此，動態量測表面磁場變化的方法未來具有發展成為監控磨鍍薄層行為的潛力。

關鍵字

表面磁場 ； 磨鍍薄層 ； 摩擦係數

並列摘要

The variations of friction coefficient and surface magnetization were measured to investigate the effects of tribo-coatings on tribo-magnetization in this study. The experiment was conducted on pairs of pure copper rubbing with iron in dry friction condition. Moreover, another eight materials such as aluminum, tin, zinc, red copper, brass, platinum, gold and silver were also selected as the pin specimen to clarify the effect of material solubility on tribo-coating and surface magnetization.
The previous study had proved that the tribo-magnetization significantly occurred by friction and wear with increasing the normal load, however, it only showed the surface demagnetization with increasing the sliding speed due to the surface temperature rises at higher sliding speeds. Therefore, the normal load and sliding speed were also selected as the major parameters in this study. By monitoring the dynamic variations of friction coefficient and surface magnetization in conjunction with SEM observations of the wear tracks, the effects of tribo-coatings on surface magnetization were investigated.
Results show that the severe friction phenomena are the necessary conditions for the tribo-magnetization. Therefore, the experimental results showed that the continuous surface magnetization variations can be used to determine the timing of material transfer. The thickness of the tribo-coatings and the absolute values of tribo-magnetization were increasing with increasing the normal loads. With increasing the sliding speeds, The tribo-coating area increased and the tribo-coating surface was smoother. The sliding distance corresponding to the timing of surface magnetization occurring was larger under high sliding speeds. On the whole, the demagnetization phenomena of Cu/Fe were different than that of Fe/Fe. However, their saturated value of surface magnetization was similar. The solubility and the higher hardness of the compound metals not only significantly influenced the tribo-coatings but also the variations of friction coefficient and surface magnetization. Therefore, the novel method of using surface magnetization variations does show great potential for evaluating the tribo-coating behavior in the future.

並列關鍵字

surface magnetization ； tribo-coatings ； friction coefficient

參考文獻

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