Papers by Author: Li Ping Zhao

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Authors: Zhu Mei Li, Li Ping Zhao
Abstract: Catastrophe analysis on financial statements of the 76 low-carbon listcompanies in 2001-2009 is used. By designing analysis indicators of financial management capacity and operating growth capacity, comprehensive performance of low-carbon business is evaluated using dimensionless analysis and mapminmax method. it finds: Overall business performanceof low-carbon businesses tends to rise, especially the financial management capacity significantly improved, but there is no continuing business development capacity, but significant decline. Responds to this, some measures are proposed: upgrad low-carbon technologies strategically,occupy low-carbon technologies high ground etc.
Authors: Jing Jing Liu, Zong De Liu, Li Ping Zhao
Abstract: With aim to investigate the effect of the content of Ni on erosion behavior of the TiC-xNi coating at elevated temperatures, The TiC-xNi (x=0, 5, 10, 15 , 20wt.%) composite coatings were in-situ synthesized on nickel-based alloy substrate by the self-developed electro-thermal explosion ultra-high speed spraying (EEUSS) device with the cored wire. Erosion properties of the coatings were assessed by the erosion tester under 90° incidence angle and 650°C. X-ray diffraction (XRD) and microhardness tester were used to investigate the coating phases and microhardness. The coatings consisted of TiC phase and Ni binder phase, as well as the residual C. The microhardness of TiC-xNi coating with the Ni content from 5 wt.% to 20wt.% decreased with the increase of the content of Ni. Elevated temperature erosion test indicate that the spiculate quartz particles impact the surface of the coating which lead to the loss of material. The erosion resistance of the TiC-xNi coatings increased first and decreased afterwards with the increase of the content of Ni. The relative erosion resistance of coating with 10 wt.% Ni addition is excellent which is about 2 times than that of TiC-20Ni coating under 650°C and 90° incidence angle.
Authors: Bin Li, Zong De Liu, Li Ping Zhao, Yi Min Ma
Abstract: Molybdenum coatings are commonly used in the industry for protection against wear. With an aim to investigate the erosion properties of this coating, molybdenum coating was sprayed onto both AISI 1045 and nickel-based superalloy (GH3039) substrate by electro-thermal explosion ultra-high speed spraying process. Phase composition, microstructure and microhardness of the coatings were analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and microhardness tester, respectively. Erosion tests of the coating at different particle impingement angel and material sample temperature were performed on a GW/CS-MS type tester. The high erosion resistance of the coating can mainly be attributed to high hardness, low porosity and metallurgical bonding between the coating and the substrate.
Authors: Bin Li, Zong De Liu, Yong Chen, Li Ping Zhao
Abstract: With an aim to investigate erosion properties, TiC/Fe composites fabricated by self -propagating high-temperature synthesis and pseudo heat isostatic pressing (SHS/PHIP) technique were studied experimentally. Phase composition, microstructure, composition and microhardness of the products are analyzed by X-ray diffraction (XRD), scanning electron microscopy (SEM) and microhardness tester, respectively. The elevated temperature erosion tests of the TiC/Fe composites were tested with the help of a GW/CS-MS type tester using SiO2 quartz and Al2O3 corundum as the abrasive. The influences of the different parameters such as impact angle, environment temperature, abrasive, on the erosion property of the TiC/Fe composites were studied. The morphology of the worn surface was analyzed with SEM to determine the erosion mechanisms.
Authors: Ming Yi Wang, Zong De Liu, Li Ping Zhao
Abstract: This paper reports an investigation of the effect of Nb additions on the microstructure of TiC–Ni cermets, which is prepared by plasma cladding technique. The composition of the cermets cladding layer was observed by scanning electron microscope (SEM) in combination with energy dispersive spectrometer (EDS), and X-ray diffraction (XRD) analysis was carried out for phase identification. The microstructure has a trend to become finer with the increase of Nb additions, however, when the Nb addition goes to 15 wt%, the ceramic particles become much bigger and cause large amounts of cracks. Then the component variation of different parts of the ceramic particle was analyzed using the EDS, and explained the reason of the variation and why the rim structure wasn't formed.
Authors: Bin Li, Zong De Liu, Li Ping Zhao, Yan Rong Bao
Abstract: The key problem about the application of TiC/Fe composite ceramics in high temperature is the oxidation resistance. With an aim to investigate oxidation properties, the high density TiC/Fe ceramics was produced by self-propagating high-temperature synthesis method combined with pseudo hot iso-static pressing (SHS/PHIP). The oxidation kinetics of TiC/Fe ceramics were investigated by means of conducting the isothermal oxidation experiments in air at temperature of 550°C  900°C for up to 150 hours, and measuring the variations of the weight gains of the composites with the oxidation times. The microstructure evolution of the composites during the oxidation processing was studied by using SEM/EDS and XRD. Experimental results show that TiC/Fe ceramics basically follows a parabolic rule at high temperature. A detailed characterization of the microstructure and distribution of the phases within the scale following oxidation studies has been undertaken to suggest the possible mechanism for the oxidation of TiC/Fe ceramics.
Authors: Jing Jing Liu, Zong De Liu, Dong Yu Liu, Li Ping Zhao, Liang Wang, Wei Chun Xi
Abstract: In this work, TiC-Ni coating was synthesized on copper substrate by electro-thermal explosion ultra-high speed spraying method at the discharge voltage of 26kV. Microstructure, phase structure, elemental distribution and microhardness of the coating were studied by means of scanning electron microscope in back-scatter-electron and secondary electron, energy-dispersive analysis X-ray spectroscopy, X-ray diffraction and Vickers hardness tester. The TiC-Ni coating, which exhibits no pores or cracks, consists of an irregular spheroidal TiC phase embedded in a nearly continuous Cu0.81Ni0.19 binder. TiC particles are uniformly distributed and the size of the TiC particle of the coating is less than 1.0 m because of the solute trapping effect. The average hardness of the TiC-Ni coating is approximately 1200 HV0.3.
Authors: Shi Xiang Hou, Zong De Liu, Dong Yu Liu, Li Ping Zhao
Abstract: Intermetallic compound MoSi2 is useful for protective coatings against high-temperature oxidation. In this study, MoSi2-based coatings were prepared using electrothermal explosion ultra-high speed spraying methods. The spraying distance from electric exploding chamber to substrate are 5mm, 10mm, 15mm and 20mm, respectively. The microstructures, phase structures and hardness of the coatings were investigated by scanning electron microscope (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and Vickers hardness tester, respectively. The result indicates that MoSi2 primary phase is synthesized. When spraying distance is 10mm, the coatings have density microstructure, submicron grains and high microhardness. The bonding of coating-substrate is metallurgical. The oxidation resistance of Mo-Si-Al coating is higher than that of Mo-Si coating.
Authors: Shi Xiang Hou, Zong De Liu, Dong Yu Liu, Li Ping Zhao, Yi Min Ma
Abstract: A new method, electro-thermal explosion ultra-high speed spraying, was utilized to produce the Mo-Si or Mo-Si-B coatings. Experimental results showed that submicron-grain pure MoSi2 phase coating and boron alloyed MoSi2-MoB2 multiphase coatings were in-situ synthesized on GH3039 nickel-based superalloy substrate. Erosion-resistance test of GH3039 nickel-based superalloy and MoSi2-based coatings were performed under high temperature(800°C) with GW/CS – MS erosion wear tester. Quartz sand was employed as erosive material. Experimental results showed that the erosion-resistance of the MoSi2-based coatings is better than that of the GH3039 nickel-based superalloy.
Authors: Zong De Liu, Bin Li, Li Ping Zhao, Yong Chen
Abstract: To characterize wear behaviors of TiC ceramic particulate-reinforced metal matrix cermets in abominable condition, wear-resistance test was practiced in grain abrasive wear with the TiC-xNi cermets in-situ fabricated by self-propagating high-temperature synthesis method combined with pseudo hot iso-static pressing. Grain abrasion test was conducted with the MLS-225 type tester. Wear resistance was evaluated as weight loss obtained after each period of 10 minutes. Wear resistance of the cermets increased with the increase of TiC content in the composites. SEM was employed to analyze the wear process and wear mechanism. SEM examination of the wear tracks in the worn surface suggests that abrasive wear mechanisms of different binder content cermets are similar. The worn surface is characterized by long and deep parallel grooves. The fracturing of bigger carbide grains and carbide framework by a fatigue process under repeated abrasion is followed by weight loss of the material.
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