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Influence of process parameters on thickness and wear resistance of rare earth modified chromium coatings on P110 steel synthesized by pack cementation

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Journal of Rare Earths 2011年第4期29卷 396-400页

作者：林乃明谢发勤吴向清田伟 School of Aeronautics Northwestern Polytechnical University Tubular Goods Research Institute China National Petroleum Corporation

The pack cementation was employed to produce rare earth modified chromium coatings on P110 steel aiming at improving its performance and increasing the usage lifetime during operation. The orthogonal array design （OAD） was applied to set experiments. Contents of NH4Cl, types of RE, contents of RE, test temperature and soaking time were the main factors, and each factor was endowed with four levels. While the range analysis and analysis of variance were used to investigate the results of OAD tests on thickness and wear resistance. The results indicated that for a promising coating with higher thickness value and excellent anti-wear property, the test temperature was the most significant process factor. The potential promising conditions for chromizing treatment were： adding 1% NH4Cl and 1% LaCl3, maintaining the test temperature at 1000 oC for 8 h. The results of verification showed that the coating formed under the optimal process parameter had a valid thickness of 28 μm and a reduction of 0.32 mg in wear resistance test.

关键词： thickness wear resistance rare earth chromium coating P110 steel pack cementation

Influence of adding various rare earths on microstructures and corrosion resistance of chromizing coatings prepared via pack cementation on P110 steel

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Journal of Rare Earths 2010年第2期28卷 301-304页

作者：林乃明谢发勤钟涛吴向清田伟 School of Aeronautics Northwestern Polytechnical University Tubular Goods Research Center of CNPC

In order to improve the corrosion resistance and increase the service lifetime of P110 steel during operation,four chromizing coatings were formed onto its surface with/without addition of rare earths via pack cementation *** surface morphologies and microstructures of the chromizing coatings were observed using scanning electron microscopy(SEM),and the phase constitutions were investigated by X-ray diffraction(XRD).Electrochemical corrosion behavior of the chromizing coatings in simulated oilfield ...

关键词： microstructure corrosion resistance chromizing coating P110 steel pack cementation rare earths

Oxidation behaviours of Nb–22Ti–15Si–2Al–2Hf–2V–(2, 14)Cr alloys with Al and Y modified silicide coatings prepared by pack cementation

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Progress in Natural Science:Materials International 2015年第5期25卷 486-495页

作者： Songming Zhang Xingrui Shi Jiangbo Sha School of Materials Science and Engineering Beihang University

Al and Y modified silicide coatings on the Nb-15Si-22Ti-（2,14）Cr-2Al-2Hf-2V alloys（where the alloy with 2 at%Cr or 14 at%Cr is hereafter referred to as 2Cr and 14 Cr alloy,respectively） was prepared by pack *** microstructural evolution and the oxidation behaviours of the coating 2Cr and 14 Cr samples at 1250 ℃ were *** 2Cr alloy consists of Nb solid solution(NbSS) and α-Nb5Si3silicide,while the Laves C15-Cr2Nb phase arised in the 14 Cr *** coating structure of the coating 2Cr sample contained the outer（Nb,X）Si2+（Nb,X）5Si3layer,the middle（Nb,X）5Si3layer and the inner undeveloped intermetallic（Nb,Ti）3（Al,X） layer,the structure of the coating 14 Cr sample consisted of the outer single（Nb,X）Si2layer,the middle（Nb,X）5Si3layer,the transition（Nb,Ti）(Cr,Al) layer and the inner（Cr,Al）2（Nb,Ti） *** coating 14 Cr sample exhibited better oxidation resistance than the coating 2Cr *** an outer single（Nb,X）Si2layer,a compact oxide scale consisting of SiO2and TiO2formed on the coating14 Cr sample,which can efficiently prevent the substrate from *** the coating 2Cr sample with an outer（Nb,X）Si2+（Nb,X）5Si3layer,the oxide scale of the SiO2,TiO2,Nb2O5and CrNbO4mixture generated,and the scale spalled out from the surface of the sample,resulting in disastrous failure.

关键词： Nb–Si based alloys pack cementation Silicide coating Oxidation behaviour

Zn-Fe and Y-modified Zn-Fe coatings on 42CrMo steel via pack cementation

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Rare Metals 2021年第8期40卷 2266-2274页

作者： Li Liu Si-Rong Yu Wen-An Cao School of Materials Science and Engineering China University of Petroleum(East China)Qingdao266580China

Zn-Fe and Y-modified Zn-Fe coatings were prepared on 42 CrMo steel through pack cementation processes at 370,390 and 410℃ for 4 h.Y modification was achieved through the co-deposition of Zn and Y_(2)O_(3).The effects of Y modification on microstructure,formation and corrosion behavior of the Zn-Fe coating were *** coating thickness increased with an increase in *** Y-modified Zn-Fe coating was thicker than the plain Zn-Fe *** the Zn-Fe coating and Y-modified Zn-Fe coating showed single-layered structures,but the overall microstructure was improved by Y *** activation energies for Zn-Fe coating and Y-modified Zn-Fe coating were 113.15 and80.65 kJ·mol^(-1),*** Zn-Fe coating consisted of FeZn_(13) and Fe11Zn40 *** effects of Y modification on the corrosion behavior of the Zn-Fe coating were evaluated through an immersion test and polarization *** results showed that the corrosion resistance was improved by Y modification.

关键词： pack cementation Coating Modification Activation energy Corrosion

Microstructures and wear resistance of chromium coatings on P110 steel fabricated by pack cementation

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Journal of Central South University 2010年第6期17卷 1155-1162页

作者：林乃明谢发勤周俊钟涛吴向清田伟 School of Aeronautics Northwestern Polytechnical University Tubular Goods Research Institute China Natio nal Petroleum Corporation

In order to obtain a high-performance surface on P110 steel that can meet the requirements in oil/gas field environment, the chromium coatings were fabricated by pack cementation. The chromium coatings differed in with/without the addition of La2O3. Scanning electron microscope （SEM）, energy dispersive X-ray spectrometer （EDS）, X-ray diffractometer （XRD） and microhardness tester were employed to investigate the surface morphologies, surface element distributions, microstructures, phase constitutions and microhardness of the coatings. Friction-wear tests of the P110 steel substrate and the coatings were conducted in air at ambient temperature and humidity. The results show that ＇uniform and continuous coatings are formed on P110 steel regardless of adding La2O3 or not. The chromium coatings consist of Cr23C6, Cr7C3, and （Cr, Fe）7C3. The La2O3-added chromium coating is more beneficial in terms of surface morphology, microstructure, thickness and microharduess as compared with the coating without adding La2O3. Chromizing treatment significantly improves the surface hardness and wear resistance of the P110 steel. The wear resistance of the tested samples can be sorted in the following sequence： La2O3-coating 〉 no RE-coating 〉bare P110 steel.

关键词： chromium coating P110 steel pack cementation La2O3 microstmcture wear resistance

DEPOSITION OF ALUMINIDE AND CHROMIUM-MODIFIED ALUMINIDE COATINGS ON TiAl ALLOYS USING THE HALIDE-ACTIVATED pack cementation METHOD

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Chinese Journal of Aeronautics 1999年第1期12卷 50-57页

作者：周春根徐惠彬北京航空航天大学材料科学与工程系北京 Pohang Unrversity of Science and Technology 韩国

The halide activated pack cementation method is utilized to deposit aluminide and chromium modified aluminide coatings on TiAl alloys. Emphasis is placed on the effect of alloying elements on the aluminizing kinetics as well as on the study of formation of chromium modified aluminide coating. The addition of a small amount of Nb and Cr in the TiAl improves significantly the aluminizing kinetics of TiAl alloys by increasing the reaction rate of active Al atoms with substrate through grain refinement as well as by increasing the solid state diffusion of Al through the formation of stable TiAl 3 layer. Cr and Al are simultaneously co deposited by diffusion into K 5 alloy, by a single step, pack cementation process. The morphologies of the coating formed on K 5 substrate, i.e., an external layer with L1 2 structure and an underlying interdiffusion zone, are presented. The mechanism for the formation of Cr modified aluminide coating is discussed.

关键词： aluminide TiAl pack cementation

A STUDY ON ALUMINIDE COATINGS ON TiAl ALLOYS BY packcementation METHOD

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Acta Metallurgica Sinica(English Letters) 2000年第6期13卷 1148-1154页

作者： C.G. Zhou, H.B. Xu and S.K. Gong (Department of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics,Beijing 100083, China) K. Y. Kim (Department of Materials Science and Engineering, Pohang University of Science and Techn

The halide-activated pack cementation method is utilized to deposit aluminide coat- ings on TiAl alloys. Emphasis is placed on the effect of alloying elements on the aluminizing behavior of TiAl alloy. The addition of a small amount of Nb or Cr in the TiAl improves significantly the aluminizing kinetics of TiAl alloys by increasing the solid-state division of Al through the formation of stable TiAl3 layer. The TiAl3 layer formed on the TiAl alloyed with Nb or Cr has better toughness than the TiAl3 formed on the non-alloyed TiAl. The reason for better toughness of the coating formed on TiAl is that partial TiAl3 with tetragonal structure was changed to high symmetry cubic L12 structure since Nb or Cr was dissolved into TiAl3. The TiAl3 layer formed on the TiAl alloyed with Nb or Cr has much better oxidation resistance than the TiAl3 layer formed on the non-alloyed TiAl. It is attributed to change in the crystal structure of TiAl3 from the brittle tetragonal DO22 to the ductile cubic L12 by addition of small amount of Nb or Cr.

关键词： TiAl alloying element pack cementation aluminizing

Mechanical behaviors and energy absorption properties of Y/Cr and Ce/Cr coated open-cell nickel-based alloy foams

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Rare Metals 2018年第8期37卷 650-661页

作者： Zhi-Li Hu Qiu Pang Guo-Qiang Ji Gao-Hui Wu State Key Laboratory of Advanced Welding and Joining HarbinInstitute of TechnologyHarbin 150001China Hubei Key Laboratory of Advanced Technology of Automobile Components Wuhan University of TechnologyWuhan 430070China School of Mechanical and Electrical Engineering Wuhan Donghu UniversityWuhan 430212China Materials Test Department China National Analytical CenterGuangzhou 510070China

In this study, Y-and Ce-modified Cr coatings applied by pack cementation method were prepared on the surface of open-cell nickel-based alloy foam. The morphologies and microstructures of Y- and Ce-modified Cr coatings with various Y and Ce contents were investigated in detail. Then, the effects of Y and Ce addition on the mechanical properties of open-cell nickel-based alloy foams were analyzed and compared. Simultaneously, the energy absorption capacity and energy absorption efficiency of the Y- and Ce-modified Cr coated alloy foams were discussed and compared at the room and high temperatures. The results show that Cr coatings containing minor amounts of rare earth element （Y and Ce） are well adhered to the nickel-based foam struts. Especially, the microstructure of the 2 wt% Ce-modified Cr coating is denser and uniform. In addition, the compressive strength and plateau stress of Y- and Ce-modified Cr coated alloy foams firstly increase and then decrease by increasing the Y and Ce contents at room and high temperatures. The energy absorption capacity of Y/Cr and Ce/Cr coated alloy foams increases linearly with the strains increasing. The Ce/Cr coated alloy foams can absorb more energy than Y/Cr coated alloy foams in the plateau and densification regions at room temperature. Compared to those at room temperature, the Y- and Ce-modified Cr coated alloy foams show higher energy absorption efficiency when deforma- tion within 10%-30% at high temperature.

关键词： Open-cell nickel-based alloy foam Y-modified Cr coating Ce-modified Cr coating pack cementation Mechanical properties

Preparation of a tantalum-based MoSi_(2)–Mo coating resistant to ultra-high-temperature thermal shock by a new two-step process

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Journal of Materials Science & Technology 2021年第22期81卷 117-122页

作者： Sainan Liu Hongtai Shen Jiawei Xu Xiaojun Zhou Jianfei Liu Zhenyang Cai Xiaojun Zhao Lairong Xiao School of Materials Science and Engineering Central South UniversityChangshaHunan410083China Center for Mineral Materials School of Minerals Processing and BioengineeringCentral South UniversityChangsha410083HunanChina Key Laboratory of Non-ferrous Metal Materials Science and Engineering Ministry of EducationCentral South UniversityChangsha410083China

To develop an ultra-high-temperature resistant coating for a reusable thermal protection system,the preparation of a tantalum-based MoSi_(2)-Mo coating by a new two-step process of multi-arc ion plating and halide activated pack cementation is *** coating has a dense structure and is well compatible with the tantalum substrate,which can be thermally shocked from room temperature to 1750℃ for 360 cycles without *** mechanism of the coating’s excellent resistance to high-temperature thermal shocks is that a strong-binding gradient interface and a dense SiO_(2) oxide scale with good oxygen resistance are formed by the high-temperature self-diffusion of Si.

关键词： Thermal shock MoSi_(2) Tantalum Multi-arc ion plating pack cementation