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International Journal of Minerals,Metallurgy and Materials 2015年第12期22卷 1273-1282页

作者： Hang Zhao Jian-jun Li Zhi-zhen Zheng Ai-hua Wang Qi-wen Huang Da-wen Zeng State Key Laboratory of Material Processing and Die & Mould Technology Huazhong University of Science & Technology

In this work, an in situ synthesized TiC-reinforced metal matrix composite （MMC） coating of approximately 350-400μm thickness was fabricated on a gray cast iron （GCI） substrate by plasma transferred arc （PTA） surface alloying of Ti-Fe alloy powder. Microhard- ness tests showed that the surface hardness increased approximately four-fold after the alloying treatment. The microstructure of the MMC coating was mainly composed of residual austenite, acicular martensite, and eutectic ledeburite. Scanning electron microscopy （SEM） and X-ray diffraction analyzes revealed that the in situ TiC particles, which were formed by direct reaction of Ti with carbon originally contained in the GCI, was uniformly distributed at the boundary of residual anstenite in the alloying zone. Pin-on-disc high-temperature wear tests were performed on samples both with and without the MMC coating at room temperature and at elevated temperatures （473 K and 623 K）, and the wear behavior and mechanism were investigated. The results showed that, after the PTA alloying treatment, the wear resistance of the sam- ples improved significantly. On the basis of our analysis of the composite coatings by optical microscopy, SEM with energy-dispersive X-ray spectroscopy, and microhardness measurements, we attributed this improvement of wear resistance to the transformation of the microstruc- ture and to the presence of TiC particles.

关键词： gray cast iron composite coatings particle-reinforced composites titanium carbide surface alloying microstructure wear

Oxidation behavior of niobized TiAl by plasma surface alloying

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Journal of University of Science and Technology Beijing 2008年第5期15卷 590-593页

作者： Dongdong Chen Wenhuai Tian Jian Wang Xiaoping Liu School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Research Institute of surface Engineering Taiyuan University of Technology Taiyuan 030024 China

Plasma surface alloying of element Nb in TiAl-based alloys and the oxidation behavior were studied. The composition and microstructure of the surface alloyed layers were investigated by means of scanning electron microscopy （SEM）,energy dispersive X-ray analysis （EDX）,and X-ray diffraction （XRD）. The experimental results indicate that the diffusion layers are formed on the TiAl substrate during the plasma niobizing process. The result from oxidation resistance investigation shows that plasma niobizing greatly improves the oxidation resistance of TiAl compared with the untreated TiAl. The role of element Nb for improving the oxidation resistance is considered to be achieved by strengthening the activity of Al,which is induced by the plasma niobizing process.

关键词： TiAl alloys plasma niobizing oxidation resistance surface alloying

Effects of TIG surface Melting and Chromium surface alloying on Microstructure, Hardness and Wear Resistance of ADI

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Journal of Iron and Steel Research International 2008年第4期15卷 86-94页

作者： A Amirsadeghi M Heydarzadeh Sohi S F Kashani Bozorg School of Metallurgy and Materials Engineering University of Tehran Tehran Iran

Microhardness and wear resistance of different rnicrostructures formed by TIG （tungsten inert gas） surface melting and chromium surface alloying （using ferrochromium） of ADI （austempered ductile iron） were studied. surface melting resulted in the formation of a ledeburitic structure in the melted zone, and this structure has a hardness up to 896 HV as compared to 360 HV in that of ADI. Moreover, chromium surface alloying resulted in the formation of different structures including：（1） a hypereutectic structure consisting of primary （Fe,Cr）7C3 carbides and a eutectic matrix of transformed austenite （into martensite and retained austenite）, as also （Fe,Cr）7C3 carbides, with a hardness of 1078 HV; （2） a hypoeutectic structure consisting of the same eutectic along with transformed primary austenite, with a hardness of 755 HV; and （3） a ledeburitic structure with an acicular morphology and a hardness of 896 HV. The results also indicated that surface melting reduced the wear rate of the ADI by approximately 37%. Also, chromium surface alloying yielded a superior wear behavior and reduced the wear rate of the treated specimens by about 38% and 70%, depending on the structures formed.

关键词： ductile iron surface alloying surface melting chromium wear resistance

HIGH-CURRENT PULSED ELECTRON BEAM: RAPID surface alloying AND WEAR RESISTANCE IMPROVEMENT

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Acta Metallurgica Sinica(English Letters) 2003年第4期16卷 276-282页

作者： J.Xu H.W.Liu Z.R.Zhou C.Dong A.M.Wu S.Z.Hao A.M.Zhang T.Xu TribologyResearchInstitute SouthwestJiaotongUniversityChengdu610031ChinaManuscriptreceived25November2002 StateKeyLab.forMaterialsModificationbyLaser IonandElectronBeamsDalianUniversityofTech-nologyDalian116024China StateKeyLaboratoryofSolidLubrication LanzhouInstituteofChemicalPhysicsTheChineseAcademyofSciencesLanzhou730000China

The present paper reports the rapid surface alloying induced by the bombardment of high-current pulsed electron beam. Two kinds of substrate materials were examined to show this effect. The first sample was a pure Al metal pre-coated with fine carbon powders prior to the bombardment, and the second alloy is the D2-Crl2MolVl mould steel pre-coated with Cr, Ti, and TiN powders. The surface elements diffuse about several micrometers into the substrate materials only after several bombardments. Tribological behaviors of these samples were characterized and significant improvement in wear resistance was found. Finally, a TEM analysis reveals the presence of stress waves generated by coupled thermal and stress fields, which was considered as the main cause of the enhanced properties.

关键词： high-current pulsed electron beam surface alloying tribology fretting wear

Effect of Counterface Materials on Friction and Wear Behavior of Double Glow Glasma Discharge surface alloying on Ti22Al25Nb Alloy

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Journal of Wuhan University of Technology(Materials Science) 2009年第1期24卷 106-110页

作者：吴红艳张平则 College of Math and Physics Nanjing University of Information Science and Technology College of Material and Technology Nanjing University of Aeronautics and Astronautics

Samples of surface chromising layer were prepared by the double glow plasma discharge technique. X-ray diffraction and X-ray photoelectron spectroscopy（XPS） analysis of dif-ferent elements confirmed the formation of chrome in the layer. Their tribological properties were investigated by pin-on-disk tribometer. Silicon nitride, GCr15, and nickel-based alloy were selected as counterface materials. Results indicated that the lowest friction coefficients and wear rate were ob-tained when substrate and chromising layer against nickel-based alloy, and tribological properties of chromising layer were better than those of substrate. The highest friction and wear rate were samples against silicon nitride alloys. In the case of three rubbing pairs, the unchangeable materials against different hardness counterfaces leaded to different wear mechanisms. Samples against silicon nitride exhibited abrasive mechanism, and when GCr15 and nickel-based alloy were used as counterface, transfer film and glaze layer formed on the contact surface, which played the main role in decreasing friction and wear.

关键词： XPS analysis surface alloying friction and wear counterface materials

Study on microstructure and properties of Mg-alloy surface alloying layer fabricated by EPC

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China Foundry 2010年第1期7卷 13-18页

作者： Chen Dongfeng Dong Xuanpu Fan Zitian Xu Qian Zhang Xiong State Key Laboratory of Material Processing and Die ＆ Mold Technology Huazhong University of Science and Technology Wuhan430074 China

AZ91D surface alloying was investigated through evaporative pattern casting （EPC） technology. Aluminum powder （0.074 to 0.104 mm） was used as the alloying element in the experiment. An alloying coating with excellent properties was fabricated, which mainly consisted of adhesive, co-solvent, suspending agent and other ingredients according to desired proportion. Mg-alloy melt was poured under certain temperature and the degree of negative pressure. The microstructure of the surface layer was examined by means of scanning electron microscopy. It has been found that a large volume fraction of network new phases were formed on the Mg-alloy surface, the thickness of the alloying surface layer increased with the alloying coating increasing from 0.3 mm to 0.5 mm, and the microstructure became compact. Energy dispersive X-ray （EDX） analysis was used to determine the chemical composition of the new phases. It showed that the new phases mainly consist of/3-MglTAI12, in addition to a small quantity of inter-metallic compounds and oxides. A micro-hardness test and a corrosion experiment to simulate the effect of sea water were performed. The result indicated that the highest micro-hardness of the surface reaches three times that of the matrix. The corrosion rate of alloying samples declines to about a fifth of that of the as-cast AZ91D specimen.

关键词： EPC magnesium alloy surface alloying corrosion rate

Microstructure and Properties of Laser surface alloying 304 Stainless Steel with Si

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Journal of Materials Science & Technology 1992年第5期8卷 335-338页

作者：李瑞国冯钧冯钟潮 Corrosion Science Laboratory Institute of Corrosion and Protection of MetalsAcademia SinicaShenyang110015.China Institute of Metal Research Academia SinicaShenyang 110015China

Silicon was added to the surface of 304 stain- less steel by laser melting the sprayed preplaced Si *** optical microscopy,X-ray diffraction and EPMA were employed to investigate the microstructure and chemical composition of the laser surface alloyed *** hardness of the al- loyed layer was measured by microhardness test and wear resistance was evaluated by scratch test. Corrosion resistance of laser alloyed sample was studied in 1N H_2SO_4+0.1N NaCl and 0.5N HCl+0.5N NaCl aqueous solutions.A microcrystalline intermetallic compound coating with smooth surface and good chemical homogeneity without porosity and crack is ob- *** hardness is about 720 *** wear re- sistance is 2 times better than that of the substrate. The corrosion resistance of the laser alloyed sample is much better than that of 304 stainless steel sample.

关键词： laser surface alloying microcrystalline intermetallic compound corrosion

Frication Property of Mo-Cr-Infiltrated Steel Layer by Plasma surface Metallurgy

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Plasma Science and Technology 2006年第4期8卷 451-456页

作者：徐晋勇康志成刘燕萍王建忠高原徐重 Taiyuan University of Technology Taiyuan 030024China Guilin University of Electronic TechnologyGuilm 541004China Guilin University of Electronic Technology Guilm 541004China Taiyuan University of Technology Taiyuan 030024China

Introduced in this article is the technique to acquire a high performance strengthened layer on carbon steel samples, namely, plasma alloying on the surface of Q235 steel and heat treatment technology. With this technique the alloying elements of Mo, Cr, and C can be obtained on the surface of Q235 steel samples. The content of the constituent elements is approximately up to high speed steels （HSS）. The surface property required for the HSS after hardening and low tempering is attained. In the test, the alloying elements Mo and Cr were penetrated into the Q235 steel samples by glow discharge sputtering so that the content of the alloyed layer on the surface of the Q235 steel samples was about 20% Mo and 10% Cr. Two kinds of experiments were conducted. One was to carry out ultra-saturated carburization. The alloyed layer＇s composition was similar to molybdenum HSS with surface carburizing of more than 2.0%. The carbides of the alloyed layer were compact, uniform and disperse without a coarse eutectic ledeburite structure, The another was ion nitriding after the alloying elements of Mo and Cr were penetrated. The first process included hardening with low tempering and hardening with cryogenic treatment for 2 hr and low tempering. The second one was ion nitriding only. It was found that the surface hardness after cryogenic treatment is up to 1600HV, much higher thanthat without cryogenic treatment. The abrasion test results indicate that, without the penetrated alloy elements Mo and Cr and without cryogenic treatment and ion nitriding, the friction coefficient is lower by one order of magnitude. The change in relative resistance is similar to the change in the friction coefficient, but without a proportional relationship,

关键词： surface alloying cryogenic treatment ion nitriding friction coefficient carbide

DC Plasma Technology Applied to Powder Metallurgy: an Overview

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Plasma Science and Technology 2013年第1期15卷 70-81页

作者： A. N. KLEIN R. P. CARDOSO H. C. PAVANATI C. BINDER A. M. MALISKA G. HAMMES D. FUSAO A. SEEBER S. F. BRUNATTO J. L. R. MUZART LabMat (Materials Laboratory) Departamento de Engenharia Mec~nica Universidade Federal de Santa Catarina (UFSC) 88040-900 FlorianSpolis - SC Brazil Departamento de Engenharia Mecanica Universidade Federal do Parana (UFPR) 81531-990 Curitiba- PR Brazil Departamento Academico de Metal-Mecanica Instituto Federal de Santa Catarina (IFSC) 88020-300 Florianopolis - SC Brazil Universidade Tecnologica Federal do Parana (UTFPR) 84016-210 Ponta Grossa - PR Brazil Centro de Ciencia e Tecnologia Universidade de Caxias do Sul 95070-560 Caxias do Sul- RS Brazil

DC plasma is a very promising technology for processing different materials, and is becoming especially interesting when low environmental impact and high-performance treatments are needed. Some of the intrinsic characteristics of DC plasma technology, which make it suitable for powder metallurgy （PM） and powder injection molding （PIM） parts production, are low- pressure processing and plasma environment high reactivity. Moreover it can be considered as a highly competitive green technology. In this work, an overview of some of the important DC plasma techniques applied to PM and PIM parts processing is presented. Emphasis is given to the descriptions of the main characteristics and the technique potentials of plasma-assisted nitriding, plasma-assisted thermal debinding, plasma-assisted sintering, and simultaneously plasma-assisted sintering and surface alloying. The aspects presented and discussed in this paper indicate that DC plasma processes are promising and competitive techniques for PM and PIM parts processing.

关键词： powder metallurgy DC glow discharge plasma nitriding plasma sintering,plasma-assisted thermal debinding surface alloying

Self-repairing functionality and corrosion resistance of in-situ Mg-Al LDH film on Al-alloyed AZ31 surface

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Journal of Magnesium and Alloys 2023年第5期11卷 1567-1579页

作者： Yi-Xing Zhu Guang-Ling Song Peng-Peng Wu Center for Marine Materials Corrosion and Protection College of MaterialsXiamen University422 S.Siming RdXiamenFujian 361005China State Key Laboratory of Physical Chemistry of Solid surfaces Xiamen University422 S.Siming RdXiamenFujian 361005China School of Mechanical and Mining Engineering The University of QueenslandBrisbaneQueensland 4072Australia

A novel Mg-Al LDH film was in-situ prepared hydrothermally in an alkaline aqueous solution on an Al-alloyed AZ31 *** structural,chemical and functional characteristics of the film were explored by means of scanning electron microscope(SEM),X-ray diffraction(XRD),energy dispersive spectrometer(EDS),polarization curve,AC impedance and salt immersion tests,*** anti-corrosion results indicated that the Mg-Al LDH film on the Al-alloyed AZ31 surface could effectively protect the AZ31 from corrosion attack even after 90 days of immersion in 3.5 wt.%NaCl *** protection performance is surprisingly better than most of the reported coatings on Mg *** interestingly,when the Mg-Al LDH film was scratched,the exposed Al-alloyed surface might gradually release metal ions and re-generate dense LDH nano-sheets in the corrosive environment to inhibit the further corrosion there,exhibiting a self-repairing *** combination of the benign long-term protection and desirable self-repairing performance in this new process of surface-alloying and LDH-formation may significantly extend the practical application of magnesium alloys.

关键词： LDH film surface alloying Corrosion resistance Self-repairing