黄杨木制备SiC木质陶瓷的性能与表征

Properties and Characterization of SiC Woodceramics Fabricated from Boxwood

SiC木质陶瓷是近年来应用前景广阔的新型陶瓷材料,以绿色可再生的木材为原材料,通过反应烧结工艺制备出的陶瓷具有优良的高温力学性能。为探究影响生物质陶瓷性能的因素,将黄杨木在800℃氮气保护下热解形成生物质炭坯,然后在1650℃和1900℃两种高温下进行熔融渗硅制备SiC木质陶瓷。利用X射线衍射仪(XRD)和扫描电子显微镜(SEM)研究SiC木质陶瓷的物相组成和微观结构,采用阿基米德排水法和三点弯曲法测定陶瓷的开孔率、密度和弯曲强度,再使用维氏硬度计测定SiC木质陶瓷的显微硬度。研究结果表明:在1650℃下通过熔融渗硅可以得到微观结构均匀的SiC木质陶瓷,在1650℃比在1900℃下熔融渗硅制备陶瓷的力学性能更优异,陶瓷的密度更大,为2.27 g/cm^(3),此时弯曲强度为192.45 MPa;游离Si会提高SiC木质陶瓷的密度,增强陶瓷的弯曲强度。

SiC woodceramics is a new type of ceramic material with broad application prospects in recent years.Using green and renewable wood as the original material,the ceramics fabricated by the reaction sintering process has excellent high-temperature mechanical properties.In order to explore the factors that affect the properties of biomass ceramic materials,boxwood was pyrolyzed under the protection of nitrogen at 800℃to form a biomass carbon template,and then SiC woodceramics were fabricated by liquid silicon infiltration at 1650℃and 1900℃.In order to determine the prepared materials and their properties,the phase composition and microstructure were studied with X-ray diffraction(XRD)and scanning electron microscopy(SEM),the porosity and density were measured by Archimedes drainage method,the bending strength of ceramics was measured by three-point bending method,and the microhardness was determined by Vickers hardness tester.The results show that SiC woodceramics with uniform microstructure are fabricated by liquid silicon infiltration at 1650℃.The mechanical properties and density(2.27 g/cm^(3))of ceramics fabricated by liquid silicon infiltration at 1650℃are better than those fabricated at 1900℃,and the bending strength is 192.45 MPa.The free Si increases the density of SiC woodceramics as well as enhances the bending strength and microhardness.