High-temperature Corrosion of AlCrTiSiN Film in Ar-1%SO 2 Gas
AlCrSiN film with a composition of 29.1Al-17.1Cr-2.1Si-51.7N in at. % was deposited on a steel substrate by cathodic arc ion plating at a thickness of 1.8 μm. It consisted of nanocrystalline hcp-AlN and fcc-CrN, where a small amount of Si was dissolved. Corrosion tests were carried out at 800 ◦C for 5–200 h in Ar-1%SO2 gas. The major corrosion reaction was oxidation owing to the high oxygen affinity of Al and Cr in the film. The formed oxide scale consisted primarily of (Al,Cr)2O3, within which Fe, Si, and S were dissolved. Even after corrosion for 200 h, the thickness of the scale was about 0.7–1.2 μm, indicating that the film had good corrosion resistance in the SO2-containing atmosphere.
Characteristics of (Cr 1−x , Al x ) N films prepared by pulsed laser deposition
Chromium aluminum nitride ((Cr 1−x , Al x ) N) films have been successfully prepared by pulsed laser deposition (PLD). The (Cr 1−x , Al x ) N film, which is hard and resistant against wear and oxidation, is one of the most promising pseudobinary nitrides for applications in the protective coatings. The film was synthesized by depositing chromium and aluminum metal vapors in nitrogen. Experiments were carried out by changing the surface area ratio of the target (Al/(Cr+Al)) from 0 to 100%. The hardness of the (Cr 1−x , Al x ) N films showed the maximum value (HV∼3000) at x = 0.75. Phase transition from B1 (NaCl) structure to B4 (wurtzite) structure occurred above x = 0.75, being in a reasonable agreement with the theoretical prediction. As a result of oxidation test, the CrN film oxidized at near 600°C, whereas the (Cr 0.5 , Al 0.5 ) N film was not detected the existence of oxide in the annealing temperature range R.T. to 900°C.
In search of optimum chest radiography techniques.
A nation-wide study of chest radiography in Sweden had previously revealed a large variation in the physical and technical factors involved, in particular the radiation dose. In this study the image quality could not be assessed unambiguously. The aim of the present study was to try to establish a correlation between visual grading of radiographs and physical and technical factors in order to find the optimum chest X-ray system. The physical and technical performance of 24 chest units was evaluated. Radiographs were taken of an anthropomorphic chest phantom supplied with test structures simulating various pathologies. Image quality was assessed by visual grading analysis of the radiographs. The physical and technical parameters of the units rated best were used to exemplify good radiographic practice. The results were in agreement with the recommendations issued by the Commission of the European Communities (CEC). It was also shown that low radiation dose is compatible with high-quality radiographic imaging of the chest.