硅树脂添加量对氧化铝基陶瓷型芯性能影响研究

Effect of silicone resin content on the properties of Al2O3-based ceramic cores

摘要:

本文以氧化铝粉末为基体,添加具有粘结性和一定陶瓷产率的硅树脂粉末,通过干压成型方法和无压烧结制备出氧化铝基陶瓷型芯,重点研究了硅树脂添加量对氧化铝基陶瓷型芯性能的影响。研究结果表明：硅树脂在裂解过程中会形成二氧化硅产物,会与氧化铝基体发生反应形成新相莫来石。由于硅树脂在交联和裂解过程中会释放大量气体,导致烧结体失重,且气体的逸出会抑制由烧结引起的收缩,因此,随着硅树脂添加量增加,产生的气体量增加,烧结体的失重率增加,收缩率降低。硅树脂含量的增加使得烧结体的气孔率变大和体积密度减小,烧结体的室温抗弯强度逐渐减小。硅树脂的添加虽然降低了其室温强度,但是保证了陶瓷型芯的尺寸精度。

Abstract:

Al₂O₃-based ceramic cores were prepared by dry-pressing and subsequent pressureless sintering, where the Al₂O₃ powders were used as the matrix and the silicone resin powders were used as the binder. The effect of the silicone resin content on the properties of Al₂O₃-based ceramic cores was investigated. Results showed that the new mullite phase was formed by the reaction between Al₂O₃ and silica which was formed by the decomposition of silicone resin. Weight loss of sintered Al₂O₃-based ceramic cores was mainly caused owing to the release of gases during the cross-linking and decomposition process of silicone resin. And the release of gases inhibited the shrinkage caused by the sintering drive force. Therefore, with the increase of silicone resin content, more and more gases were released. As a result, the weight loss of Al₂O₃-based ceramic cores gradually increased and the shrinkage rate gradually decreased. The increasing silicone resin content made the apparent porosity increase and the bulk-density decrease, leading to the decrease of bending strength in sintered Al₂O₃-based ceramic cores. Although the addition of silicone resin decreased the bending strength, the dimensional precision was improved markedly.