Effect of sintering parameters on the porosity of TiNi powder intermetallic compound

Due to the increase in the average age of the country's population, there is a growing need for joint replacement, restoration of the musculoskeletal system and in the field of dentistry. The main treatment for these diseases involves the use of implants to replace or strengthen the affected bone tissue. Metal materials are the most in demand due to the combination of high mechanical properties and corrosion resistance. The effectiveness of using implants depends on several factors – biochemical, biomechanical, and histological compatibility. Biomechanical compatibility is determined by the correspondence of the elastic modules of the bone tissue and the implanted structure. Titanium nickelide, TiNi, which has the lowest Young's modulus, stands out among the new metal alloys for implantation. The creation of porous materials can further bring the values of the elastic constants of the implant material and bone tissue closer and, in addition, ensure good integration of the implant with bone structures. It is proposed to use powder metallurgy methods to create porous titanium nickelide. TiNi powder obtained by calcium hydride reduction is sintered according to different temperature and time regimes - temperatures ranged from 900 to 1290$^\circ$ C, duration - from 10 to 360 min. 24 sintering modes were implemented and samples with different porosities were obtained. Statistical processing of the obtained results showed that the sintering duration factor has no effect in the studied time range. The dependence of porosity on the sintering temperature is described by an exponential equation. It is shown that the porosity varies slightly up to temperatures of 1200$^\circ$ C, and at higher sintering temperatures it sharply decreases to minimum values. The results of the study showed that obtaining TiNi samples with different porosities will require precise compliance with the sintering temperature regime. In this case, the time factor does not play a significant role in the change in porosity.