配位沉淀—熱分解法制備纖維狀銀粉
發(fā)布時間：2018-08-01 08:38
【摘要】： 超細粉末的用途與性能密切相關,而性能很大程度上取決于其形貌和顆粒尺寸。作為微電子工業(yè)關鍵材料的銀粉,人們對其形貌有著特殊的要求。目前國內外制備的銀粉大都為球狀,為了增加銀粉顆問的接觸面以提高導電性能,通常需將球狀銀粉細磨成片狀。纖維狀的導電材料可以形成網狀導電回路,能有效提高導電材料的導電性能。因此,作者綜合分析了目前國內外銀粉的制備方法,結合本課題組制備超細金屬或合金粉體材料的經驗,提出了采用配位沉淀-熱分解法來制備纖維狀銀粉的新工藝,并研究了新工藝過程的理論基礎。 本文首先根據同時平衡原理和質量守恒原理,推導出了常溫下Ag(Ⅰ)-C2O42--NH3-NH4+-H2O體系熱力學平衡的數學模型,計算并繪制了該體系的金屬離子濃度對數-pH圖,確定了配位沉淀法制備前驅體實驗研究的pH值范圍。在此基礎上,實驗研究了溶液體系各項物理化學條件對前驅體粒度和形貌的影響,結果表明：兩段式添加沉淀劑的反加料方式,反應溫度為60℃,Ag+濃度為0.4mol/L,溶液的pH值為3.8～4.8,加料30min,陳化30min,攪拌速率600r/min,PVP的加入量為m(PVP)/m(AgNO3)=0.1時能制備得到棒狀前驅體。 本文還根據熱分解過程的熱力學理論分析了草酸銀鹽直接熱分解得到金屬銀粉的可行性和銀粉的熱穩(wěn)定性。系統(tǒng)研究了前驅體形貌、熱分解溫度、熱分解時間和氣氛對熱分解產物的影響。結果表明：在VN2：VCO2=3：1的氣氛中,熱分解溫度為140℃,升溫0.5h,保溫2.5h時可制備得到分散性良好的纖維狀銀粉,比表面積達1.054m2/g。
[Abstract]:The use of ultrafine powders is closely related to their properties, and their properties depend to a great extent on their morphology and particle size. As a key material in microelectronics industry, silver powder has special requirements for its morphology. At present, the silver powder prepared at home and abroad is mostly spherical. In order to increase the contact surface of silver powder to improve the electrical conductivity, it is usually necessary to fine grind the silver ball powder into flake shape. The fibrous conductive material can form a network conductive circuit, which can effectively improve the conductive properties of conductive materials. Therefore, the author synthetically analyzed the preparation methods of silver powder at home and abroad, combined with the experience of our group in the preparation of ultrafine metal or alloy powder materials, and put forward a new technology of preparing fibrous silver powder by coordination precipitation-thermal decomposition method. The theoretical basis of the new process is also studied. Based on the principle of simultaneous equilibrium and mass conservation, the mathematical model of thermodynamic equilibrium of Ag (鈪，
本文編號：2157007
[Abstract]:The use of ultrafine powders is closely related to their properties, and their properties depend to a great extent on their morphology and particle size. As a key material in microelectronics industry, silver powder has special requirements for its morphology. At present, the silver powder prepared at home and abroad is mostly spherical. In order to increase the contact surface of silver powder to improve the electrical conductivity, it is usually necessary to fine grind the silver ball powder into flake shape. The fibrous conductive material can form a network conductive circuit, which can effectively improve the conductive properties of conductive materials. Therefore, the author synthetically analyzed the preparation methods of silver powder at home and abroad, combined with the experience of our group in the preparation of ultrafine metal or alloy powder materials, and put forward a new technology of preparing fibrous silver powder by coordination precipitation-thermal decomposition method. The theoretical basis of the new process is also studied. Based on the principle of simultaneous equilibrium and mass conservation, the mathematical model of thermodynamic equilibrium of Ag (鈪，
本文編號：2157007
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