Vacuum

Thermomechanical properties of TiAlCeSiN

Data and raw materials of Figures, Tables, Highlights, and Graphical Abstract.

The experimental apparatus, conditions and procedures are described in the paper. “rundown data” is measured speed data during deceleration in different pressure.

Fig. 2. Comparison between Al0.24Ga0.76N band-gap energy and energy spectra of photons emitted from 280- and 310-nm LEDs. The energy spectrum of photons emitted from a blacklight lamp is also drawn in the same figure [22]. Fig. 3. Comparison between F/Ga, N/Ga, and Al/Ga ratios of the as-grown AlGaN surface and the AlGaN surface irradiated for 5 min with CF4 plasma only. Fig. 4. (a) F/Ga, (b) N/Ga, and (c) Al/Ga ratios of AlGaN surfaces irradiated simultaneously with CF4 plasma and UV at wavelengths of 280 and 310 nm, as a function of UV intensity. The results at an UV intensity of 0 mW/cm2 correspond to those caused by CF4 plasma-only irradiation. Fig. 5. F 1s regions in XPS spectra of AlGaN surfaces irradiated simultaneously with CF4 and UV at wavelengths of (a) 280 and (b) 310 nm. The results at an UV intensity of 0 mW/cm2 correspond to those caused by CF4 plasma-only irradiation. Fig. 6. Comparison between CFx fractions of the surfaces irradiated simultaneously with CF4 and UV at wavelengths of 280 and 310 nm, as a function of UV intensity. The result at an UV intensity of 0 mW/cm2 correspond to those caused by CF4 plasma-only irradiation. Fig. 7. (a) An AFM image and (b) a height profile along a straight green line of AlGaN surface irradiated simultaneously with CF4 plasma and 280 nm-UV at 3 mW/cm2.

Fig. 2. MB dye photodecomposition, ln(C/C0), of (a) TiO2 thin films treated with the heat-assisted plasma and the plasma only, and (b) TiO2 thin films annealed at a variety of gas pressures, as a function of UV irradiation time. Fig. 3. XRD patterns of TiO2 thin films treated with the heat-assisted plasma and the plasma only at a gas pressure of 100 kPa. Fig. 4. Optical absorption coefficients of TiO2 thin films treated with the heat-assisted plasma and the plasma only at a gas pressure of 100 kPa. Energy spectrum of photons emitted from a blacklight lamp used is also drawn in the same figure. Fig. 5. (a) O/Ti ratios for oxygen species adsorbed onto the surfaces of TiO2 thin films treated with the heat-assisted plasma and the plasma only at a gas pressure of 100 kPa. (b) O/Ti ratios for the O–Ti bond of the plasma-treated surfaces. Fig. 6. XRD patterns of TiO2 thin films annealed at a variety of gas pressures. Fig. 7. O/Ti ratios for oxygen species adsorbed onto the surface of TiO2 thin films annealed at a variety of gas pressures. Fig. 8. Comparison between MB dye photodecomposition rates, MB dye adsorption rates, and net MB dye photodecomposition rates of TiO2 thin film treated with the heat-assisted plasma and TiO2 nanoparticle powder, ST-01.

In this work, we obtained high flexural strength C/C composites, and they had lower density comparing with pure C/C composites. And the high flexural strength kept in different C/C composits. However, the flexural strength of all C/C-Al2O3 composites decreased when they experienced heat treatment higher than 1500℃. And when the temperature was higher than 2100℃, the flexural strength of all C/C-Al2O3 composites was lower than pure C/C composites. The reason was that their structure changed when temperature was higher than 1500℃. In order to exlpain and repeat the high flexural strength of C/C-Al2O3 composites, 2D needle-punched carbon felts with a density of 0.4 g/cm3 were heat-treated under 2450 ℃ for 2 h and then used as starting materials. Pure CH/C composites and three different CH/C-Al2O3 composites were prepared from the 2D needle-punched carbon felts, and the content of Al2O3 in carbon felts is 4.5 wt% (CH/C-5AlO), 10.7 wt% (CH/C-10AlO) and 14.9 wt% (CH/C-15AlO) before densification. And the subsequent procedures and processes were the same as fabricating C/C- Al2O3 composites.And the flexural strength of pure CH/C composites (79.6 MPa / 84.9 MPa) was only half of that of pure C/C composites (171.01 MPa / 161.64 MPa) which the 2D needle-punched carbon felts were not heat-treated. When Al2O3 was introduced into CH/C composites, their flexural strength increased significantly and were 150.1 MPa / 142.5 MPa for CH/C-5AlO, 191.9 MPa / 197.5 MPa CH/C-10AlO and 228.8 MPa / 201.7 MPa for CH/C-15AlO. Because the teat treatment had important influence on the flexural strength of C/C- Al2O3 composites, thermal conductivity and coefficient of thermal expansion were carried out at different temperature to study the effect of temperature on the thermo-physical properties of C/C- Al2O3 composites.The thermal diffusivity and conductivity of C/C-10AlO composites changed with the temperature in the same way between different directions. But mutations happened at about 1500 ℃, the reason was that Al2O3 reacted with C above 1500 ℃ and the microstructure changed in some way. This phenomenon also happened in the coefficient of thermal expansion of C/C-10AlO composites. The CTE of C/C-10AlO composites also kept steady before 1500 ℃, but it increased when the temperature is higher than 1500 ℃. And the CTE kept increasing with increasing temperature. The thermo-physical test indicated that the change all happened at about 1500 ℃, so it supposed that the structure and phases of C/C-Al2O3 composites changed after 1500 ℃, and then causing the decrease of their flexural strength.

ToF-ERDA data from witness samples and reference samples; Surface profiler raw data for fig. 3

Related Article: Jinhao Zhang, Wenjia Hao, Yulan Song, Tao Huang, Rufang Peng, Bo Jin|2022|Vacuum|206|111503|doi:10.1016/j.vacuum.2022.111503