In order to improve oxidation/erosion resistance of the T/P 24 steel components used in advanced power plants, chrome carbide coatings were prepared by PIRAC (Powder Immersion Reaction Assisted Coating) on T/P24 at 700-1000°C. Microstructure and phase composition of the obtained surface layers were characterized employing X-ray diffraction and scanning electron microscopy with chemical analysis (SEM/EDS). Results showed that homogenous smooth chrome carbide coatings can be formed on the substrate. Phase composition of the prepared coatings are differs with PIRAC temperatures. Prepared at lower temperatures or short times treatment, Cr23C6, Cr7C3 and Cr3C2 can be detected in the coatings. While, at higher temperatures or longer treatment times, Cr23C6 is subtotal phase of the produced coating. Moreover, the lower the PIRAC temperature is, the more of Cr7C3 and Cr3C2 are. Thermodynamics calculation based on Gibbs free energy is applied to explain phase composition difference of the coatings.

In the present work, effect of field irrigation on tensile behaviors of disposable drip tape made from virgin PE is studied. Results show that after 5 months (from Novomber, 2012 to next April, 2013) field irrigation tests, there are no intrinsically changes in tensile stress-strain behaviors for the disposable drip tape made from virgin PE along the longitudinal direction. Tensile stress-strain behaviors for the disposable drip tape made from virgin PE along transverse direction is different. After field irrigation tests, the tapes are prone to sudden rupture at the seams accompanied with a relative smaller elongation and acute stress drops while those as-received show large elongation with gradual stress decrease under transverse tensile. However, rebound of the stretched tapes after field irrigation tests is distinctly smaller than those of as-received samples.

In the present work, Ti and Ti-6Al-4V were PIRAC nitrided at the relatively low temperatures of 700-850°C. To obtain thicker TiN layers, 3 stage PIRAC based coating was applied: (1) PIRAC nitriding followed by (2) PIRAC titanizing followed by (3) additional PIRAC nitriding. The microstructure and phase composition of the obtained surface layers were characterized employing X-ray diffraction and scanning electron microscopy with chemical analysis (SEM/EDS). Bending test was employed to evaluate the coatings adhesion to the substrate. Lower PIRAC nitriding temperatures yielded smoother TiN coatings with a more gradual microhardness decrease from the surface to the bulk. All PIRAC TiN based coatings have excellent adhesion to substrate – no delamination of the coating in bending tests was observed. The best combination of microhardness and adhesion was obtained using 3 stage PIRAC process.

No abstract

A fuzzy-PID temperature controller with excellent Man-machine interface was developed employing fuzzy-PID control theory combined with uC/OS-II embedded system based on S3 C2440, ARM9 kernel produced by the Samsung Company. The development is aim at improving overshoot and regulation delay in the existing temperature acquisition and control system. Reducing of regulation time and improvement of precision was achieved by using fuzzy-PID control without any accurate mathematical model. While shorten time and improve efficiency of development were achieved by transplantation of the uC/OS-II operating system.