本文選題：稻殼 + 多孔陶瓷��； 參考：《安徽理工大學》2017年碩士論文

【摘要】：稻殼作為農業(yè)廢棄物,主要元素為C、O、H和Si,且雜質含量低,并含有高活性的無定形SiO_2。預處理后,為低溫常壓下碳熱還原氮化法制備高性能硅質多孔陶瓷提供硅源、碳源及成孔劑。研究了燒結溫度、燒結助劑種類及摻量、稻殼摻量等對硅質多孔陶瓷(包括多孔β-Si_3N_4陶瓷、多孔α-Si_3N_4陶瓷、多孔碳化硅陶瓷及多孔氧氮化硅陶瓷)性能的影響。主要研究內容如下:以C/SiO_2為0.7的碳化稻殼和α-Si_3N_4為原料,MgO-CeO_2為燒結助劑,研究了 CeO_2摻量和燒結溫度對制備多孔β-Si_3N_4陶瓷性能的影響。當CeO_2的摻量為4-5%、1500-1550℃下可制備出多孔β-Si_3N_4陶瓷,其顯氣孔率為45.78-42.81%,抗彎強度為49.44-82.09 MPa;當CeO_2摻量為5%、1550℃的多孔β-Si_3N_4陶瓷中,長柱狀β-Si_3N_4發(fā)育良好。以C/SiO_2為0.7的碳化稻殼和α-Si_3N_4為原料,研究燒結助劑種類及摻量、稻殼摻量對稻殼制備多孔α-Si_3N_4陶瓷性能的影響。當La_2O_3.摻量為2-4%、1400℃-1450℃時,試樣中主晶相為α-Si_3N_4,α-Si_3N_4相發(fā)育良好。當La_2O_3摻量為4%,燒結溫度為1450℃時,所得多孔α-Si_3N_4陶瓷的綜合性能最佳,抗彎強度達最大值(60.45 MPa),顯氣孔率為26.84%,介電常數(shù)為4.65。改變稻殼摻量可以明顯提高多孔陶瓷的顯氣孔率;介電常數(shù)隨著顯氣孔率的增加而急劇下降。以C/SiO_2為0.6的碳化稻殼和SiC為原料,研究燒結溫度和燒結助劑種類及摻量對稻殼制備多孔碳化硅陶瓷性能的影響。當燒成溫度為1550℃時,Al_2O_3摻量為6%時,成功制備出多孔碳化硅陶瓷,陶瓷斷面孔洞較多,晶粒為六方狀的α-SiC,當燒成溫度為1550℃時,Al_2O_3摻量為4-6%時,多孔碳化硅陶瓷的宏觀性能也最佳,顯氣孔率為27.88-30.35%,抗彎強度為40.67-42.49 MPa。以C/SiO_2為0.4的碳化稻殼為主要原料,添加少量燒結助劑,研究燒結溫度和稻殼摻量對稻殼制備多孔氧氮化硅陶瓷性能的影響。在1400℃-1450℃保溫2h燒成了以氧氮化硅為主相的多孔陶瓷。摻70-80%的碳化稻殼在1450-1500℃下燒成的多孔陶瓷的綜合性能較好,其抗彎強度為31.84-53.76 MPa,顯氣孔率為42.76%-27.83%。摻70%碳化稻殼1500℃燒成試樣中,Si_2N_2O晶粒呈板狀,氣孔分布均勻;該多孔陶瓷的抗氧化性優(yōu)異,在1100℃的空氣氣氛中煅燒1h,氧化增重量僅為2.57%。
[Abstract]:Rice husk is a kind of agricultural waste with low impurity content and high activity amorphous SiO-2, the main elements of which are Con O O H and Si. After pretreatment, silicon source, carbon source and pore-forming agent were provided for the preparation of high performance silicon porous ceramics by carbothermal reduction nitriding under low temperature and atmospheric pressure. The effects of sintering temperature, type and amount of sintering aids and rice husk on the properties of porous silicon ceramics (including porous 尾 -Si _ 3N _ 4 ceramics, porous 偽 -Si _ 3N _ 4 ceramics, porous sic _ 3N _ 4 ceramics, porous silicon carbide ceramics and porous silicon oxynitride ceramics) were studied. The main contents of the study are as follows: the effects of CEO _ 2 content and sintering temperature on the properties of porous 尾 -Si _ 3N _ 4 ceramics were studied by using the carbonized rice husks with C / SiO _ 2 as 0.7 and 偽 -Si3N _ 4 as raw materials and MgO-CeO _ 2 as sintering auxiliaries. Porous 尾 -Si _ 3N _ 4 ceramics can be prepared when the content of CeO2 is 4-5 ~ 1500-1550 鈩，

本文編號：2037659