Research On Microstructure And Thermal Physical Properties Of TiB2/Si-Al Composites For Electronic Packing

In this paper, in situ spray forming reaction and hot isostatic pressing technologies were used to prepare TiB₂/Si-Al electronic packaging materials.Various methods including OM, XRD, SEM were used to analysis the relationships between the phase and the microstructure, thermal conductivity and thermal expansion coefficient of the materials. The results showed that the TiB₂ particles in Si-Al alloy made by in situ reaction distributed uniformly in the primary Si phases, and the primary Si phase had been significantly refined with uniform sizes. With the increase of TiB₂ particles, the refinement effect was more remarkable. Meanwhile the Si grain sizes were larger with the increase of Si content in the TiB₂/Si-Al composites. The density of TiB₂/Si-Al composites was effectively improved by hot isostatic pressing process.By the application of P.G.?P.G. Klemens?, H-J?Hasselman-Johnson? and MEMA?Multiple-effective-medium-approximation? model, we studied the change rule of thermal conductivity of composites with variation of TiB₂ and Si contents. It turned out that the thermal conductivity decreased with the increase of TiB₂ particles and Si contents. But a small scale change?1%²%? of TiB₂ particles has little effect on the thermal conductivity of composites. The Hasselman-Johnson model formula was also modified by the measured results.The thermal expansion coefficient of Si-Al alloys and TiB₂/Si-Al composites showed that the thermal expansion coefficient of Si-Al composites decreases with the increase of Si content and the decrease of temperature. The thermal expansion coefficient of 60Si-Al alloy under hot isostatic pressing process is lower than that of the deposition state in the more elevated temperature zone. By making use of ROM, Turner and Kerner models, the thermal expansion coefficient of the Si-Al alloys and TiB₂/Si-Al composites were investigated and results showed that the thermal expansion coefficient of Si-Al composites decreases with the increase of Si content. The simulation of Kerner model is the closest one to the measured values in three models.