凝胶发泡法制备多孔NiTi合金及其性能

以TiH2粉和雾化Ni粉为原料,采用凝胶注模发泡技术制备多孔镍钛合金,研究了琼脂及羟丙基甲基纤维素(HPMC)用量对浆料流动性、生坯强度及多孔合金孔隙结构与性能的影响。结果表明,琼脂用量对浆料黏度及生坯强度均有较大影响,随着其用量增加,浆料黏度及生坯强度均增加;适量提高HPMC添加量,对浆料黏度影响不大,但对提高生坯强度有利,且能显著影响发泡效果及后继烧结体孔隙结构。在此基础上,制备了孔隙率41.3%~56.5%、杨氏模量11.6~18.3 GPa、抗压强度113.2~280.6 MPa且具有多级孔隙结构的多孔NiTi合金,其孔隙结构及力学性能与人体骨相匹配。

Preparation and Properties of Porous NiTi Alloy by Gel-Foaming

Porous NiTi alloy was prepared by a combined technology of gel-casting and foaming, with TiH2 powder and atomized Ni powder as raw materials. The effects of the dosage of agar and hydroxypropyl methyl cellulose (HPMC) on slurry fluidity, green strength, as well as pore structure and properties of porous alloy were studied. The results show that the amount of agar has a great influence on the viscosity of the slurry and the green strength. As the amount of agar increases, both the viscosity of the slurry and the green strength increase. And appropriately increasing the HPMC content brings little change in the slurry viscosity, but is beneficial to improving the green strength and can significantly affect the foaming effect and pore structure of subsequent sintered product. On this basis, a porous NiTi alloy with the multi-stage pore structure is prepared with porosity of 41.3%~56.5%, Young's modulus of 11.6~18.3 GPa and compressive strength of 113.2~280.6 MPa, which meets the requirement for pore structure and mechanical properties as the material in bone implants.