The oxidation behavior of Hastelloy C-2000 alloy was investigated in air at 800 °C and 1000 °C for 100 h, respectively. Oxidation kinetics and oxide scales morphologies were examined by mass gain measurement...The oxidation behavior of Hastelloy C-2000 alloy was investigated in air at 800 °C and 1000 °C for 100 h, respectively. Oxidation kinetics and oxide scales morphologies were examined by mass gain measurement, scanning electron microscopy（SEM）, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS）. The oxidation behavior of the alloy approximately follows a parabolic rate law. Moreover, annealing twins defect structure in matrix deteriorates the oxidation resistance of alloy due to the improvement of diffusion rates for alloying elements and oxygen atoms. At 800 °C, the microstructure is primarily composed of Ni O and Cr1.3Fe0.7O6 and the initial annealing twins structure is visible and Mo-rich phases are emerged to approach boundary of oxide scales. At 1000 °C, however, the morphology microstructure of oxide scales consists of oxide particle with fine Cr oxides and large Ni oxides by inlaying each other, whilst Mo-rich phases hardly appear closing to the interface of oxide scales.展开更多
C-2000前置放大器采用了Accuphase特有的AAVA(Accuphase Analog Vari—gain Amplifier，金嗓子模拟可变增益放大器)音量控制设计，其音量控制的步级数可达216级，即65536级之多，可以实现非常精确的调节。此外，AAVA还能有效提高整机的...C-2000前置放大器采用了Accuphase特有的AAVA(Accuphase Analog Vari—gain Amplifier，金嗓子模拟可变增益放大器)音量控制设计，其音量控制的步级数可达216级，即65536级之多，可以实现非常精确的调节。此外，AAVA还能有效提高整机的信噪比并保持不变的频响特性。展开更多
基金Project(2013AA031004)supported by the National High-tech Research and Development Program of China
文摘The oxidation behavior of Hastelloy C-2000 alloy was investigated in air at 800 °C and 1000 °C for 100 h, respectively. Oxidation kinetics and oxide scales morphologies were examined by mass gain measurement, scanning electron microscopy（SEM）, X-ray diffraction（XRD） and X-ray photoelectron spectroscopy（XPS）. The oxidation behavior of the alloy approximately follows a parabolic rate law. Moreover, annealing twins defect structure in matrix deteriorates the oxidation resistance of alloy due to the improvement of diffusion rates for alloying elements and oxygen atoms. At 800 °C, the microstructure is primarily composed of Ni O and Cr1.3Fe0.7O6 and the initial annealing twins structure is visible and Mo-rich phases are emerged to approach boundary of oxide scales. At 1000 °C, however, the morphology microstructure of oxide scales consists of oxide particle with fine Cr oxides and large Ni oxides by inlaying each other, whilst Mo-rich phases hardly appear closing to the interface of oxide scales.
文摘C-2000前置放大器采用了Accuphase特有的AAVA(Accuphase Analog Vari—gain Amplifier，金嗓子模拟可变增益放大器)音量控制设计，其音量控制的步级数可达216级，即65536级之多，可以实现非常精确的调节。此外，AAVA还能有效提高整机的信噪比并保持不变的频响特性。
