纳米Al2O3改性SiBCN陶瓷高温粘接剂的制备与性能研究

Preparation and Properties of Ceramics Composed of Nano Al2O3 and Polysiloxane-polyborosilicate-TiB2 Modified Polysilborazane as High Temperature Adhesive for SiC Based Ceramics

为了进一步提高PSO-PBSZ-TiB2改性PSNB胶粘剂(标记为PPPT)的热稳定性和粘接强度,通过添加纳米Al2O3制备出了新的复合胶粘剂(标记为PPPTA),研究了其与SiC陶瓷片的粘接性能。采用SEM和XRD等测试方法,分析了改性粘接剂的微观结构和物相组成,研究了裂解温度和纳米Al2O3对SiBCN陶瓷的微观结构和粘接强度的影响,揭示了纳米Al2O3对SiBCN陶瓷的强韧化机理。结果表明,在120℃空气中固化2 h,然后在1000℃空气中裂解2 h后,PPPT和PPPTA室温粘接强度最高分别达到11.23和15.91 MPa,在800℃空气中的高温剪切强度分别达到10.4和12.1 MPa。分析表明,添加纳米Al2O3可同时有效抑制粘接层的体积收缩和玻璃相在高温时的挥发,从而显著提高粘接强度。

In order to improve the thermal stability and adhesion strength of PSO(polysiloxane)-PB-SZ(polyborosilicate)-TiB2modified PSNB(polysilborazane)(labeled as PPPT),PSNB was modified by Al2O3-PSO-PBSZ-TiB2(denoted as PPPTA),and it was used for joining SiC ceramic discs.The microstructure and phase composition of the modified adhesive were analyzed by SEM and XRD.The effect of pyrolysis temperature and addition amount of nano-Al2O3on the microstructure and adhesion strength for the bonding pair of SiBCN ceramics were investigated.The strengthening and toughening mechanism of nano-Al2O3to the bonding SiBCN ceramics was revealed.After curing in air at 120℃for 2 h and then pyrolysis in air at 1000℃for 2 h,the room temperature adhesion strength of PPPT and PPPTA is up to11.23 and 15.91 MPa,respectively,and more importantly,the high temperature(in air at 800℃)shear strength reaches 10.4 and 12.1 MPa,respectively.The analysis shows that nano-Al2O3can effectively suppress the volume shrinkage of the adhesive layer and inhibit the volatilization of the glass phase at high temperature,thereby significantly improving the adhesion strength.