碳化硅陶瓷的无压液相烧结及性能研究
发布时间：2018-11-26 12:08
【摘要】：作为性能优异的高温结构材料,碳化硅陶瓷已广泛地应用于石油化工、航空航天、机械密封、电子封装等领域,因此,开展碳化硅陶瓷的力学及热学性能的研究具有十分重要的意义。无压液相烧结由于工艺简单、烧结温度低、制品的力学性能优异,已成为一种很有发展前途的烧结技术。而烧结助剂的合理选择是该技术中的重要研究内容。本论文以α-SiC与β-SiC为主要原料,分别引入La_2O_3-Y_2O_3、AlN-Y_2O_3-MgO和AlN-Y_2O_3-La_2O_3-MgO三种助烧剂,采用无压液相烧结工艺制备了6个体系的30个碳化硅陶瓷样品,并对其物相、表面形貌、密度、力学及热学性能进行了测量与分析。1)SiC-La_2O_3-Y_2O_3系列陶瓷的研究结果表明:随着烧结助剂含量的增加,不同配比α-SiC-La_2O_3-Y_2O_3陶瓷的密度、相对密度、硬度、热导率呈现完全相同的变化趋势,热膨胀系数则呈现单边上升趋势;而不同配比β-SiC-La_2O_3-Y_2O_3陶瓷的的密度、相对密度及硬度呈现先增加后减小的变化规律,热膨胀系数则呈现先减小后增加的变化趋势;在所有10个样品中,烧结助剂为9wt.%的α-SiC-La_2O_3-Y_2O_3陶瓷的各项性能均最优,它的密度、相对密度、硬度分别为3.1169g/cm3、93.13%、1021.000kgf/mm2,热导率为112.495W/(m·K),热膨胀系数为0.3181×10-6/K。2)SiC-AlN-Y_2O_3-Mg O陶瓷的研究结果表明:烧结助剂含量的变化,对SiC-AlN-Y_2O_3-MgO陶瓷的密度、硬度、热导率、热膨胀系数都产生了明显的影响,相同配比的β-SiC-AlN-Y_2O_3-MgO和α-SiC-AlN-Y_2O_3-MgO陶瓷的密度和硬度相比,后者总是优于前者,而热导率和热膨胀系数的变化比较复杂;在相应的10个样品中,烧结助剂含量为19.5wt.%α-SiC-AlN-Y_2O_3-MgO陶瓷的密度、相对密度及硬度最大,分别为3.3481g/cm3,98.8%;助剂含量为22wt.%α-SiC-AlN-Y_2O_3-MgO陶瓷硬度最大,为1929.933kgf/mm2;助剂含量为17%的β-SiC-AlN-Y_2O_3-MgO热膨胀系数最小为1.51×10-6/K;22wt.%的β-SiC-AlN-Y_2O_3-MgO陶瓷热导率最大,为103.367W/(m·K)。3)SiC-AlN-Y_2O_3-La_2O_3-Mg O陶瓷的研究结果表明:烧结助剂含量为17%的α-SiC-AlN-Y_2O_3-La_2O_3-MgO和β-SiC-AlN-Y_2O_3-La_2O_3-MgO陶瓷的密度、相对密度、硬度均为最大,密度分别为3.1764g/cm3,3.0555g/cm3,相对密度分别为92.16%,86.76%,硬度分别为1753.800kgf/mm2,2323.433kgf/mm2;助剂含量为12wt.%时α-SiC-AlN-Y_2O_3-La_2O_3-MgO与β-SiC-AlN-Y_2O_3-La_2O_3-MgO两组陶瓷体系的热膨胀系数有最小值,分别为1.4554×10-6/K、0.2220×10-6/K;助剂含量为14.5wt.%时α-SiC-AlN-Y_2O_3-La_2O_3-Mg O陶瓷体的导热率最大,在50℃下,其热导率为69.479W/(m·K),助剂含量为22.0wt.%时β-SiC-AlN-Y_2O_3-La_2O_3-MgO陶瓷的导热率最大,在50℃时,其导热率可达63.396W/(m·K)。
[Abstract]:As a high temperature structure material with excellent performance, silicon carbide ceramics have been widely used in petrochemical, aerospace, mechanical sealing, electronic packaging and other fields. It is of great significance to study the mechanical and thermal properties of sic ceramics. Due to its simple process, low sintering temperature and excellent mechanical properties, pressureless liquid sintering has become a promising sintering technology. The reasonable selection of sintering additives is an important research content in this technology. In this paper, 伪-SiC and 尾-SiC were used as main raw materials, and La_2O_3-Y_2O_3,AlN-Y_2O_3-MgO and AlN-Y_2O_3-La_2O_3-MgO were introduced respectively. 30 silicon carbide ceramic samples were prepared by pressureless liquid phase sintering process, and their phase, surface morphology and density were analyzed. The mechanical and thermal properties were measured and analyzed. 1) the research results of SiC-La_2O_3-Y_2O_3 series ceramics show that: with the increase of the content of sintering auxiliaries, The density, relative density, hardness and thermal conductivity of 伪-SiC-La_2O_3-Y_2O_3 ceramics with different ratios showed the same change trend, while the thermal expansion coefficient showed a unilateral upward trend. The density, relative density and hardness of 尾-SiC-La_2O_3-Y_2O_3 ceramics with different ratios increased first and then decreased, while the coefficient of thermal expansion decreased first and then increased. Among all the 10 samples, the 伪-SiC-La_2O_3-Y_2O_3 ceramics with 9 wt.% sintering aids have the best properties. Its density, relative density and hardness are 3.1169 g / cm ~ (3 93) ~ (13) and 1021.000 kg / m ~ (2) / m ~ (-2), respectively. The study on the thermal conductivity of 0.3181 脳 10-6/K.2 SiC-AlN-Y_2O_3-Mg O ceramics with 112.495W/ (m K), thermal expansion coefficient shows that the content of sintering aids varies. The density, hardness, thermal conductivity and thermal expansion coefficient of SiC-AlN-Y_2O_3-MgO ceramics are obviously affected. Comparing the density and hardness of 尾-SiC-AlN-Y_2O_3-MgO and 伪-SiC-AlN-Y_2O_3-MgO ceramics with the same ratio, the latter is always better than the former, while the variation of thermal conductivity and thermal expansion coefficient is more complex. The density, relative density and hardness of 伪-SiC-AlN-Y_2O_3-MgO ceramics containing 19.5 wt.% 伪-SiC-AlN-Y_2O_3-MgO were the highest, which were 3.3481g / cm ~ 398.8, respectively. The hardness of 22wt.% 伪-SiC-AlN-Y_2O_3-MgO ceramics was the highest (1929.933kg / m ~ (-2) and the thermal expansion coefficient of 尾-SiC-AlN-Y_2O_3-MgO with 17% additive content was 1.51 脳 10 ~ (-6) / kg 路m ~ (-2) 路L ~ (-1) 路min ~ (-1). 22wt.% 尾-SiC-AlN-Y_2O_3-MgO ceramics have the highest thermal conductivity. The results of study on SiC-AlN-Y_2O_3-La_2O_3-Mg O ceramics with 103.367W/ (m K). 3 show that 伪-SiC-AlN-Y_2O_3-La_2O_3-MgO with a content of 17% of sintering aids is obtained. And the density of 尾-SiC-AlN-Y_2O_3-La_2O_3-MgO ceramics, The relative density and hardness were 3.1764g / cm ~ (-3) and 3.0555g / cm ~ (-3), respectively. The relative densities were 92.16kg / cm ~ (-2) and 86.76%, respectively, and the hardness were 1753.800 kg / m ~ (-2) and 2323.433 kg / m ~ (2) respectively. The thermal expansion coefficient of 伪-SiC-AlN-Y_2O_3-La_2O_3-MgO and 尾-SiC-AlN-Y_2O_3-La_2O_3-MgO ceramic systems is minimum when the additive content is 12 wt.%, which is 1.4554 脳 10 ~ (-6) / K, respectively. 0.2220 脳 10 ~ (-6) / K; The thermal conductivity of 伪-SiC-AlN-Y_2O_3-La_2O_3-Mg O ceramics is the highest when the additive content is 14.5 wt.%, and the thermal conductivity is 69.479W/ (m K), at 50 鈩，
本文编号：2358518
[Abstract]:As a high temperature structure material with excellent performance, silicon carbide ceramics have been widely used in petrochemical, aerospace, mechanical sealing, electronic packaging and other fields. It is of great significance to study the mechanical and thermal properties of sic ceramics. Due to its simple process, low sintering temperature and excellent mechanical properties, pressureless liquid sintering has become a promising sintering technology. The reasonable selection of sintering additives is an important research content in this technology. In this paper, 伪-SiC and 尾-SiC were used as main raw materials, and La_2O_3-Y_2O_3,AlN-Y_2O_3-MgO and AlN-Y_2O_3-La_2O_3-MgO were introduced respectively. 30 silicon carbide ceramic samples were prepared by pressureless liquid phase sintering process, and their phase, surface morphology and density were analyzed. The mechanical and thermal properties were measured and analyzed. 1) the research results of SiC-La_2O_3-Y_2O_3 series ceramics show that: with the increase of the content of sintering auxiliaries, The density, relative density, hardness and thermal conductivity of 伪-SiC-La_2O_3-Y_2O_3 ceramics with different ratios showed the same change trend, while the thermal expansion coefficient showed a unilateral upward trend. The density, relative density and hardness of 尾-SiC-La_2O_3-Y_2O_3 ceramics with different ratios increased first and then decreased, while the coefficient of thermal expansion decreased first and then increased. Among all the 10 samples, the 伪-SiC-La_2O_3-Y_2O_3 ceramics with 9 wt.% sintering aids have the best properties. Its density, relative density and hardness are 3.1169 g / cm ~ (3 93) ~ (13) and 1021.000 kg / m ~ (2) / m ~ (-2), respectively. The study on the thermal conductivity of 0.3181 脳 10-6/K.2 SiC-AlN-Y_2O_3-Mg O ceramics with 112.495W/ (m K), thermal expansion coefficient shows that the content of sintering aids varies. The density, hardness, thermal conductivity and thermal expansion coefficient of SiC-AlN-Y_2O_3-MgO ceramics are obviously affected. Comparing the density and hardness of 尾-SiC-AlN-Y_2O_3-MgO and 伪-SiC-AlN-Y_2O_3-MgO ceramics with the same ratio, the latter is always better than the former, while the variation of thermal conductivity and thermal expansion coefficient is more complex. The density, relative density and hardness of 伪-SiC-AlN-Y_2O_3-MgO ceramics containing 19.5 wt.% 伪-SiC-AlN-Y_2O_3-MgO were the highest, which were 3.3481g / cm ~ 398.8, respectively. The hardness of 22wt.% 伪-SiC-AlN-Y_2O_3-MgO ceramics was the highest (1929.933kg / m ~ (-2) and the thermal expansion coefficient of 尾-SiC-AlN-Y_2O_3-MgO with 17% additive content was 1.51 脳 10 ~ (-6) / kg 路m ~ (-2) 路L ~ (-1) 路min ~ (-1). 22wt.% 尾-SiC-AlN-Y_2O_3-MgO ceramics have the highest thermal conductivity. The results of study on SiC-AlN-Y_2O_3-La_2O_3-Mg O ceramics with 103.367W/ (m K). 3 show that 伪-SiC-AlN-Y_2O_3-La_2O_3-MgO with a content of 17% of sintering aids is obtained. And the density of 尾-SiC-AlN-Y_2O_3-La_2O_3-MgO ceramics, The relative density and hardness were 3.1764g / cm ~ (-3) and 3.0555g / cm ~ (-3), respectively. The relative densities were 92.16kg / cm ~ (-2) and 86.76%, respectively, and the hardness were 1753.800 kg / m ~ (-2) and 2323.433 kg / m ~ (2) respectively. The thermal expansion coefficient of 伪-SiC-AlN-Y_2O_3-La_2O_3-MgO and 尾-SiC-AlN-Y_2O_3-La_2O_3-MgO ceramic systems is minimum when the additive content is 12 wt.%, which is 1.4554 脳 10 ~ (-6) / K, respectively. 0.2220 脳 10 ~ (-6) / K; The thermal conductivity of 伪-SiC-AlN-Y_2O_3-La_2O_3-Mg O ceramics is the highest when the additive content is 14.5 wt.%, and the thermal conductivity is 69.479W/ (m K), at 50 鈩，
本文编号：2358518
本文链接：https://www.wllwen.com/kejilunwen/huagong/2358518.html
