凝胶注模多孔NiTi合金的固化工艺及动力学研究

Research on curing process and kinetics of gel casting of porous NiTi alloy

摘要:

以氢化脱氢钛粉和雾化镍粉为原始粉末，甲基丙烯酸羟乙酯（HEMA）-1,6-己二醇二丙烯酸酯（HDDA）为凝胶体系，采用凝胶注模法制备多孔NiTi合金。研究了引发剂、催化剂、固化温度及固相体积分数对固化过程的影响。结果表明：随着引发剂及催化剂加入量的增加，固化时间降低，最佳的催化剂N,N-二甲基苯胺(DMA）用量为1.5 wt.%，引发剂过氧化苯甲酸叔丁酯(TBPB）用量为2 wt.%；固化反应随着固化温度及固相体积分数的增加而加快；根据DSC测试结果，计算得到HEMA-HDDA-TBPB-DMA凝胶体系的固化反应表观活化能为61.52 kJ/mol，反应级数为0.91。在最佳固化工艺条件下，利用50 vol.%镍钛浆料制备了孔隙率为32.68%、抗压强度为331 MPa，且具有三维连通双级孔隙结构的多孔NiTi合金。

Abstract:

Porous NiTi alloy was prepared by the gel injection method using titanium powder and atomized nickel powder as the original powder and hydroxyethyl methacrylate (HEMA)-1,6-hexanediol diacrylate (HDDA) as the gel system. The effects of initiator, catalyst, curing temperature and solid volume fraction on the curing process were investigated. The results showed that the curing time decreased with the increase of initiator and catalyst addition, and the best amount of catalyst N,N-dimethylaniline (DMA) was 1.5 wt.%, and the amount of initiator tert-butyl peroxybenzoate (TBPB) was 2 wt.%; The curing reaction was accelerated with the increase of curing temperature and solid phase volume fraction; Based on the DSC test results, the apparent activation energy of the curing reaction of the HEMA-HDDA-TBPB-DMA gel system was obtained as 61.52 kJ/mol, and the reaction order was 0.91. Porous NiTi alloy with porosity of 32.68%, compressive strength of 331 MPa and three-dimensional connected two-stage pore structure was prepared using 50 vol.% Ni Ti slurry under the optimal curing process conditions.