Résumé
Today, literature is weak regarding thermal coefficients of NiTi, i.e. heat capacity(Cp) and thermal conductivity(k), for Austenitic and Martensitic phases for temperature from -50℃ to +200℃. No literature is reported concerning the R-phase. Results diverge about the value for Cp, from CpA=CpM to CpA=0,75 CpM. Difference is bigger for the k values, varying from kM=0.5 kA to kM=1.5 kA. No study of potential k anisotropy is referenced. All studies used thermocouples. Temperature changes are done by laser heating, Joule effect or natural cooling. In every thermal problem, difficulties are the estimation of radiance and convection terms. In our works, we use thin specimens, and the surface temperature is measured with Infra red camera. Experiments consist on the analysis of the thermal field during natural cooling from an homogeneous temperature T1 to a temperature T2. Cooling can be homogeneous in 0D or heterogeneous in 1D or 2D. A reference′ sample with known thermal properties is put on the side of the studied sample to evaluate convection and radiance terms. Analysis of the time-space temperature evolution allows the determination of physical properties in every point of the sample. In that study we used two samples. They are respectively Austenitic and Martensitic at room temperature. Thus, we determined thermal properties of every phase.