TFT-LCD廢玻璃混合轉爐石爐渣熱處理資材化製成絕緣玻璃陶瓷之研究

Abstract

本研究之目的係以TFT-LCD廢玻璃與一貫作業煉鋼爐渣轉爐石經高溫熱處理製成具優良介電特性、機械性質及低熱膨脹係數之絕緣玻璃陶瓷材料。基於廢玻璃與轉爐石之組成具有形成符合良好絕緣特性MgO-Al2O3-SiO2(MAS)系玻璃陶瓷之可行性，本研究選定TFT-LCD廢玻璃與轉爐石比為6：4及7：3配比進行熱處理，並添加10-20 % MgO(w/w)、15-20 % Al2O3(w/w)、10 % TiO2(w/w)等調質劑進行調質，以符合MAS系玻璃陶瓷組成，並探討添加調質劑後對晶相與熱處理溫度之影響。另針對TFT-LCD廢玻璃與轉爐石比為7：3添加不同比例調質劑包含MgO、Al2O3及TiO2¬等之配比進行性質分析，研析溫度對熱性質與機械強度之影響，評估以TFT-LCD廢玻璃與轉爐石作為絕緣玻璃陶瓷之潛力與可行性。 實驗結果顯示廢玻璃與轉爐石比為7：3添加20 % MgO、15-20 % Al2O3之配比經熱處理析出玻璃陶瓷系統之結晶相，包括CaO-Al2O3-SiO2 (CAS)系玻璃陶瓷中矽灰石與鈣長石結晶相、MAS系玻璃陶瓷中鎂橄欖石與白矽石結晶，顯示添加純物質於廢棄物配比中，具有形成優良特性如機械特性、熱性質與介電特性之玻璃陶瓷潛力。添加成核劑TiO2能促使結晶於較低溫度析出外，亦無TiO2結晶相產生而達到相分離及幫助晶相成長之作用，但會使屬MAS系玻璃陶瓷晶相之鎂橄欖石強度減弱，而降低玻璃陶瓷熱性質及機械性質等。 本研究選定TFT-LCD廢玻璃與轉爐石比為7：3之配比，添加不同比例之MgO及Al2O3，進行熱分析及機械分析。共添加15-20 % MgO(w/w)及20 % Al2O3(w/w)，於室溫至200℃具有較低之熱膨脹係數(CTE)，且與矽晶片之CTE相近，應用於電子陶瓷構裝上能與矽晶片有高接合度；於980℃時，抗壓強度具最大值732 Mpa；抗折強度最大值為257.6 Mpa。實務上考量機械特性對後續玻璃陶瓷製程之良率影響，建議熱處理溫度範圍介於860至900 ℃，可獲致低熱膨脹係數及高抗壓強度與抗折強度之玻璃陶瓷。綜合本研究之試驗結果，TFT-LCD廢玻璃與轉爐石經MgO及Al2O3調質後，經熱處理程序有形成具絕緣特性玻璃陶瓷之潛力。

The objective of this study was to use thin film liquid crystal display (TFT-LCD) waste glasses from optoelectronic industry and basic oxygen furnace (BOF) slags from integrated steel plant as reused materials to produce insulated glass ceramic materials that have superior dielectic and mechanical properties with low coefficient of thermal expansion . This study selected the ratio of TFT-LCD waste glass to BOF slag as 6：4 and 7：3 by weight based on quenched vitreous slag composition which has the feasibility to initiate good insulating properties of MgO-Al2O3-SiO2 (MAS) glass ceramic system. The vertification of MAS glass-ceramic system was conducted by addition of 10-20 % MgO (w/w)、15-20 % Al2O3 (w/w) and 10 % TiO2 (w/w) , and analysed the effect of addition of modifier on crystal phases and thermal treatment temperature. In addition,regarding property analysis corresponding to the ratio of TFT-LCD waste glass to BOF slag as 7：3 (w/w) with various proportions of modifier, the effect of temperature on thermal properties and mechanical properties as well as the assessment of potentiality of material reultilized from mixing TFT-LCD waste glass and BOF slag which formed the insulating glass-ceramics were investigated . The results showed that the ratios were precipitated crystalline via heat treatment when TFT-LCD waste glass and BOF slag in the ratio of 7：3 with addition of 20 % MgO and 15-20 % Al2O3 (w/w) , which contained anorthite and wollastonite in the CaO-Al2O3-SiO2 (CAS) , forsterite and cristobalite in the MgO-Al2O3-SiO2 (MAS) system. The above crystalline phases in glass-ceramic systems are consequently suitable for thermal shock resistant and insulation. Besides the production of crystalline phases in lower temperature, it also contributed to phase separation and crystal growth due to addition of TiO2. But TiO2 addition resulted in the decrease of phase relative intensity of forsterite in MgO-Al2O3-SiO2 (MAS) system,it also indirected affected the specimens on thermal and mechanical properties. The optimal operational conditions to reutilize wastes as insulating glass ceramics could be found as follows. (1)TFT-LCD waste glass and BOF slag in the ratio of 7：3 with MgO addition of 15-20 % and Al2O3 addition of 20 %. (2)The resulted low coefficient of thermal expansion similar to microchip’s which could be applied to electronic ceramic package.(3)One-step sintering and heat treatment at 980 ℃ for 0.5h could be employed to obtain glass-ceramics with flexural strength up to about 257.6 MPa and compressive strength up to about 732 MPa. Mechanical properties will influence the yield on glass-ceramic process in pratical operation, and the sintered materials could meet the required properties in the range between 860 ℃and 900 ℃.