牙科用鎳鉻合金與陶瓷結合界面微結構

Abstract

本實驗以牙科臨床用Ni-Cr合金及IPS-Classic V瓷粉為研究.由於Ni-Cr合 金/琺瑯間的鍵結強度受機械鍵結及化學鍵結影響甚鉅,而機械鍵結主要決 定於表面型態,化學鍵結則決定於氧化層的厚度.故本研究將以噴砂及拋光 兩步驟改變表面型態,而以氧化時間及氧化氣氛來改變氧化層厚度,並輔以 機械彎曲來量化琺瑯與合金之附著性.並利用TEM及SEM等分析儀器來了解 界面微結構與化學成份.研究結果顯示:(1)經TEM及SEM分析,燒瓷過程中琺 瑯之化學成份將擴散至合金界面處,並形成一反應層,且有KAlSi2O6, KAlSi3O8,NaAlSi3O8及TiOx等結晶粒子析出.(2)機械式錨點結合在Ni-Cr 合金與琺瑯間鍵結上占著重要地位.而隨著氧化時間的增加,界面氧化物濃 度將趨於飽和,且有提高琺瑯附著性的趨勢.(3)經機械彎曲測試知,Ni-Cr 合金/琺瑯系統的破裂屬於Cohesive形式.(4)本實驗之試片經機械彎曲策 得最佳製程條件為:合金經噴砂處理且在空氣中預氧化12分鐘,其琺瑯附著 性最佳.

The materials studied in this research were clinic-used dental Ni-Cr alloy andIPS-Classic V porcelains.It is known that two mechanisms,mechanical interlockand chemical reactions,control the bonding strength of alloys and porcelains.The contribution of the mechanical interlock is determined by the surface topography of the alloys,while the chemical reactions are influenced mainlyby the thickness of oxides layers.Both sandblasting and mechanical polishing were used to change the surface topography of the Ni-Cr alloy in the study.Also oxidation time and atmosphere were varied to produce different thickness of oxide layer.The adhesion of the Ni-Cr alloy/ porcelain was evaluaced by abending test,while the interfacial microstructure and chemistry were investigated by the state-of- the-art- transmission electron microscopy(TEM)and scanning electron microscopy(SEM).The experimental results revealed that:(1)A reaction zone,composed of crystalline KAlSi2O6,KAlSi3 O8,NaAlSi3O8 and TiOx identified by TEM and SEM,was observed near the Ni-Cr alloy/porcelain interfaces.(2)The number of anchor points at the interface plays an important role in controlling its bonding strength.It is also noted that the adhesion is improved with oxidation time and oxigen partial pressure ,presumably due to the saturation of oxides near the interface.(3)According to the failure analysis of the bending test specimens,the fracture mode between the alloy and porcelain belongs to cohesive.(4)The optimun condition of surface pretreatment for the best adhesion between the Ni-Cr alloy and porcelain is to sabdblast and then oxide the alloy for 12minutes in air before enamelling.