Nanchang Hangkong University

About: Nanchang Hangkong University is a education organization based out in Nanchang, China. It is known for research contribution in the topics: Microstructure & Alloy. The organization has 7004 authors who have published 5270 publications receiving 62162 citations. The organization is also known as: Nanchang Aviation University.

Electropolishing of titanium alloy under hydrodynamic mode

Abstract: Titanium (Ti) alloys are widely used in aerospace industry due to the low density and high corrosion resistance. However, machining and polishing remain great challenges because of the hardness and chemical stability. With a home-made electrochemical machining workstation, cyclic voltammetry is performed at a wide potential range of [0 V, 20 V] to record the details of passivation and depassivation processes under a hydrodynamic mode. The results show that the thickness of viscous layer formed on the alloy surface plays a crucial effect on the electropolishing quality. The technical parameters, including the mechanical motion rate, polishing time and electrode gap, are optimized to achieve a surface roughness less than 1.9 nm, which shows a prospective application in the electrochemical machining of Ti and it alloys.

Formation of Amorphous Calcium Carbonate and Its Transformation Mechanism to Crystalline CaCO3 in Laminar Microfluidics

Abstract: For traditional experimental methods, the dynamic formation and transformation of amorphous calcium carbonate (ACC) are hard to be captured due to its metastability and ease of transforming rapidly to the more stable phase. The emergence of microfluidic technology provides an effective approach on that issue, thus attracting widespread researchers interest in crystallization research. In this study, based on laminar microfluidics, we demonstrate a microfluidic approach toward the study of the formation and transformation of ACC. Through the control of velocity and concentration of CaCl2 and Na2CO3, the crystallization process was observed on chip under the microscope. We show by in situ confocal Micro Raman spectroscopy and theoretical calculation based on fluid dynamics simulation that the phase transformation pathways are different under the different supersaturation level in laminar microfluidics. ACC doesn't always appear in the crystallization process, when the supersaturation above the critical supe...