ZrO_(2)增强聚合物先驱体SiCNO复合陶瓷的制备和力学性能

Preparation and mechanical properties of ZrO_(2)-reinforced polymer-derived SiCNO composite ceramics

聚合物先驱体陶瓷(polymer-derived ceramics,PDCs)技术具有制造简单、成分可调等优点,为制备新型陶瓷提供了有效途径。然而,由于热解过程中微小分子的逃逸形成孔洞缺陷,先驱体技术制备的无定形聚合物衍生SiCNO陶瓷(PDCs-SiCNO陶瓷)的力学性能较差。为解决上述问题,通过向陶瓷基体添加第二相(颗粒强化)来实现增强先驱体陶瓷。对聚乙烯基硅氮烷(PVSZ)和ZrO_(2)进行先球磨后热解,制备ZrO_(2)颗粒增强PDCs-SiCNO复合陶瓷(PDCs-SiCNOZrO_(2)),研究PDCs-SiCNO-ZrO_(2)复合陶瓷的结构和力学性能。结果表明:引入的ZrO_(2)填料作为增强体嵌入SiCNO陶瓷基体中,不仅能有效降低线收缩率,还能大幅提高PDCs-SiCNO-ZrO_(2)复合陶瓷的力学性能。添加10%(质量分数)ZrO_(2)的PDCs-SiCNO-ZrO_(2)复合陶瓷的弯曲强度和压缩强度分别为197.03 MPa和375.2 MPa,比PDCs-SiCNO陶瓷高出64%和267%,其硬度值最高可达20.92 GPa,断裂韧度达到2.76 MPa·m^(1/2)。适当含量ZrO_(2)的加入有助于提升PDCsSiCNO陶瓷基体的致密化程度,从而提升了PDCs-SiCNO-ZrO_(2)复合陶瓷的力学性能。

Polymer derived ceramics(PDCs)technology has the advantages of simple manufacturing and adjustable composition,providing an effective way to prepare new types of ceramics.However,due to the escape of tiny molecules during the pyrolysis process,the pore defects are formed,and amorphous polymer derived SiCNO ceramics(PDCs SiCNO ceramics)produced by precursor technique have poor mechanical properties.To solve the aforementioned problems,enhancement of the polymer-derived ceramics is achieved by adding a second phase(particles reinforcement)to the ceramic matrix.A method was proposed to obtain ZrO_(2) reinforced PDCs-SiCNO composite ceramics(PDCs-SiCNO-ZrO_(2))by ballmilling of polyvinylsilazane(PVSZ)and ZrO_(2) followed by pyrolyzing.The phase structure and mechanical properties of PDCs-SiCNO-ZrO_(2) composite ceramics were investigated,respectively.The results show that the introduced ZrO_(2) fillers are embedded in the matrix of PDCs-SiCNO ceramic as a reinforcement,which not only can effectively reduce the linear shrinkage,but also greatly enhance the mechanical properties of the PDCs-SiCNO-ZrO_(2) composite ceramics.PDCs-SiCNO-ZrO_(2) composite ceramics with a 10%(mass fraction)ZrO_(2) addition have the flexural and compressive strengths of 197.03 MPa and 375.2 MPa,which are 64%and 267%greater than those of PDCs-SiCNO ceramics.The highest hardness value can reach 20.92 GPa,and the fracture toughness can reach 2.76 MPa·m^(1/2).The addition of appropriate content of ZrO_(2) contributes to the densification of the PDCs-SiCNO ceramic matrix,which enhances the mechanical properties of the PDCs-SiCNO-ZrO_(2) composite ceramics.