摘 要
本研究主要探討添加鈮(Nb)元素對矽固溶強化肥粒體基球墨鑄鐵(Si-SSF SG Cast Iron)微觀組織、線性往復式滑動磨耗性能及腐蝕行為影響。實驗結果顯示，Si-SSF SG Cast Iron隨著添加Nb含量增加，將有助於其基地相中晶粒間的連結而強化，且容易形成含Nb碳化物晶出，也因此容易導致在晶界處產生聚集現象。硬度分析結果，添加過量Nb反而可能導致材料硬度下降。X光繞射構成相分析結果顯示，主要組成相為α-Fe相，隨著Nb含量的增加，Nb與碳原子形成碳化物，使NbC相的訊號峰變得更明顯。在拉伸試驗中，適量添加Nb可促進碳化物細化、晶粒改變及晶界強化，便可以提升材料之韌性，於添加0.8 wt. %Nb之拉伸強度、降伏強度及伸長率表現較為優異，可明顯展現出Nb對於材料行能的提升。從Si-SSF SG Cast Iron的磨耗試驗結果可得知，添加過量Nb會導致NbC聚集，將導致機械性能下降，容易產生滑槽及溝槽等磨耗機制，造成耐磨耗性能下降。腐蝕測試分析後，在鑄態有添加及未添加Nb含量的改變與傳統FCD600之腐蝕電位及腐蝕電流密度並未明顯發現差異，添加Nb在鑄態中可提升材料之電阻能力，有些許提升耐腐蝕性能作用。關鍵字：鈮元素、矽固溶強化、球墨鑄鐵、線性往復式、滑動磨耗、腐蝕
ABSTRACT
This study primarily investigates the effects of adding niobium (Nb) on the microstructure, linear reciprocating sliding wear performance, and corrosion behavior of silicon solution-strengthened ferritic spheroidal graphite cast iron (Si-SSF SG Cast Iron). The results reveal that increasing Nb content enhances the continuity between grains in the matrix, contributing to structural strengthening and facilitating the formation of Nb-containing carbides, which tend to aggregate along grain boundaries. Hardness analysis suggests that excessive Nb addition may lead to a slight reduction in hardness. X-ray diffraction confirms α-Fe as the primary phase, with Nb addition promoting NbC formation, as evidenced by a more prominent diffraction peak. Tensile test results show that an appropriate amount of Nb, particularly 0.8 wt.%, refines carbides, modifies grain structure, and reinforces grain boundaries, thereby improving toughness and resulting in superior tensile strength, yield strength, and elongation. Wear test results indicate that excessive Nb causes carbide aggregation, adversely affecting mechanical performance and leading to groove-type wear mechanisms and reduced wear resistance. Corrosion analysis indicates no significant differences in corrosion potential or current density between Nb-added and non-added as-cast alloys or with conventional FCD600. However, the presence of Nb in the as-cast condition slightly improves the material’s electrical resistance, contributing to marginally enhanced corrosion resistance.
Keywords: Niobium Element Silicon Solid Solution Strengthening,, Spheroidal Graphite Cast Iron, Linear Reciprocating, Sliding Wear , Corrosion