聚碳硅烷对低碳铝碳材料结构与性能的影响
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摘要
为了提高低碳铝碳耐火材料的高温性能,以板状刚玉、电熔白刚玉、α-Al_2O_3微粉、鳞片石墨为主要原料,环保沥青、液态热塑性酚醛树脂、固态树脂粉、固态聚碳硅烷和正己烷为外加剂,研究了聚碳硅烷外加量(加入质量分数分别为0、0. 3%和0. 6%)和热处理温度(950、1 100、1 250、1 400和1 550℃)对低碳铝碳材料显微结构、强度及抗热震性的影响。结果表明:经950℃热处理后,聚碳硅烷热解破坏酚醛树脂热解碳结构; 1 100～1 250℃时,聚碳硅烷生成网状结构,弥补材料强度;当聚碳硅烷外加量为0. 6%(w),于1 550℃热处理后,聚碳硅烷高温裂解生成含Si纤维,材料强度提高。但含Si纤维的生成,会引起材料热膨胀失配,从而导致试样热震后的强度保持率下降。
In order to improve the high temperature properties of low-carbon Al_2O_3-refractories,tabular corundum,white fused corundum,α-Al_2O_3 micropowder,and flake graphite were used as raw materials,and environment-friendly pitch,thermal plastic phenolic resin liquid,solid resin powder,solid polycarbosilane( PCS) and n-hexane as additives. Effects of PCS extra-additions( 0,0. 3% and 0. 6%,by mass) and heattreatment temperatures( 950,1 100,1 250,1 400 and 1 550 ℃) on microstructure,strength and thermal shock resistance of low-carbon Al_2O_3-C refractories were studied. The results show that: PCS pyrolyzes and destroys the pyrolytic carbon structure of phenolic resin at 950 ℃. The reticulate structure forms by PCS pyrolysis from 1 100 ℃ to 1 250 ℃,thus the material strength increases. When the extra-addition of PCS is 0. 6% and the heat-treatment temperature is 1 550 ℃,Si-containing whiskers form,which enhance the strength greatly. But the formed Si-containing whiskers will result in the mismatch of thermal expansion of the material,thus the retention ratio of the strength after thermal shock declines.
In order to improve the high temperature properties of low-carbon Al_2O_3-refractories,tabular corundum,white fused corundum,α-Al_2O_3 micropowder,and flake graphite were used as raw materials,and environment-friendly pitch,thermal plastic phenolic resin liquid,solid resin powder,solid polycarbosilane( PCS) and n-hexane as additives. Effects of PCS extra-additions( 0,0. 3% and 0. 6%,by mass) and heattreatment temperatures( 950,1 100,1 250,1 400 and 1 550 ℃) on microstructure,strength and thermal shock resistance of low-carbon Al_2O_3-C refractories were studied. The results show that: PCS pyrolyzes and destroys the pyrolytic carbon structure of phenolic resin at 950 ℃. The reticulate structure forms by PCS pyrolysis from 1 100 ℃ to 1 250 ℃,thus the material strength increases. When the extra-addition of PCS is 0. 6% and the heat-treatment temperature is 1 550 ℃,Si-containing whiskers form,which enhance the strength greatly. But the formed Si-containing whiskers will result in the mismatch of thermal expansion of the material,thus the retention ratio of the strength after thermal shock declines.
引文
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[8]廖宁,李亚伟,桑绍柏,等.纳米炭黑和鳞片石墨对低碳铝碳材料性能的影响[J].耐火材料,2015,49(1):6-12.
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[11]宋麦丽,傅利坤.SiC先驱体---聚碳硅烷的应用研究进展[J].中国材料进展,2013,32(4):243-248.
[12]吴义伯,张国建,刘春佳,等.聚碳硅烷制备连续Si C纤维的不熔化处理工艺研究进展[J].材料导报,2006,20(7):80-83,87.
[13]HASEGAWA Y,OKAMURA K.Synthesis of continuous silicon carbide fiber part3:Pyrolysis process of polycarbosilane and structure of the products[J].J Mater Sci,1983,18(12):3633-3648.
[14]赵玉梅.聚碳硅烷结构研究[D].长沙:国防科学技术大学,2005.
[15]所俊.SiC陶瓷及其复合材料的先驱体高温连接及陶瓷金属梯度材料的制备与连接研究[D].长沙:国防科学技术大学,2005.
[2]李红霞,刘国齐,杨彬,等.连铸用功能耐火材料的发展[J].耐火材料,2001,35(1):45-49.
[3]徐海芳,王爱东,吴振刚.连铸用耐火材料对洁净钢的影响及其发展[J].连铸,2007(2):42-45.
[4]刘广华,姚金甫,田守信,等.Al2O3-C耐火材料抗氧化性研究进展[J].耐火材料,2011,45(2):137-140.
[5]李红霞,杨彬,刘国齐,等.钢液对连铸用含碳耐火材料的侵蚀作用研究[J].耐火材料,2007,41(3):161-167.
[6]邵铁钢.镁碳质耐火材料的使用寿命分析[J].科技风,2010(1):244.
[7]马世春,韩俊华.低碳Al2O3-C耐火材料研究的新进展[J].耐火材料,2017,51(3):235-240.
[8]廖宁,李亚伟,桑绍柏,等.纳米炭黑和鳞片石墨对低碳铝碳材料性能的影响[J].耐火材料,2015,49(1):6-12.
[9]雷晓谋.酚醛树脂原位催化裂解碳纳米管的生成及其应用研究[D].武汉:武汉科技大学,2008.
[10]杨文刚,杨凤玲,李红霞,等.沥青种类和硝酸镍对铝碳材料性能与结构的影响[J].耐火材料,2016,50(5):325-328.
[11]宋麦丽,傅利坤.SiC先驱体---聚碳硅烷的应用研究进展[J].中国材料进展,2013,32(4):243-248.
[12]吴义伯,张国建,刘春佳,等.聚碳硅烷制备连续Si C纤维的不熔化处理工艺研究进展[J].材料导报,2006,20(7):80-83,87.
[13]HASEGAWA Y,OKAMURA K.Synthesis of continuous silicon carbide fiber part3:Pyrolysis process of polycarbosilane and structure of the products[J].J Mater Sci,1983,18(12):3633-3648.
[14]赵玉梅.聚碳硅烷结构研究[D].长沙:国防科学技术大学,2005.
[15]所俊.SiC陶瓷及其复合材料的先驱体高温连接及陶瓷金属梯度材料的制备与连接研究[D].长沙:国防科学技术大学,2005.