Fabrication of porous Cu-Ti alloys with tunable compositions and structures via vapor phase alloying-dealloying

Abstract

Porous Cu-Ti alloys are promising for advanced applications but remain challenging to fabricate through conventional dealloying due to the refractory nature of Ti and its susceptibility to passivation. Herein, we report a fully gaseous approach that seamlessly integrates vapor phase alloying (VPA) with subsequent vapor phase dealloying (VPD) for the synthesis of porous Cu-Ti alloys. This study demonstrates that the VPA process effectively incorporates Zn into various pristine alloys (Cu₉₅Ti₅, Cu₅₀Ti₅₀, and Ti₉₅Cu₅), forming Cu-Ti-Zn intermediate phases. Subsequent VPD, through the selective sublimation of Zn, yields a bicontinuous ligament-pore structure. Notably, the initial alloy composition dictates the final microstructure: a uniform porous framework forms from Cu₉₅Ti₅, a regularly aligned, comb-like architecture with secondary pores emerges from Ti₉₅Cu₅, and a unique composite structure with surface-enriched Cu develops from Cu₅₀Ti₅₀. Specially, the formation of the composite structure in porous Cu₅₀Ti₅₀ is discussed based upon the Gibbs free energy of formation of Ti-Zn and Cu-Zn, the diffusion and saturated vapor pressure of Ti and Cu, which results in different alloying scenarios of Ti and Cu with Zn during VPA. This work not only establishes the VPA-VPD method as a versatile and damage-free route for creating porous alloys from challenging systems, but also provides fundamental insights into the solid-state diffusion mechanisms governing structure evolution.

Keywords

Vapor phase alloying / Vapor phase dealloying / Porous solid solution / Porous intermetallic alloy / Microstructural regulation

Declaration of Competing Interest

Zhonghua Zhang is an editorial board member for ChemPhyMater and was not involved in the editorial review or the decision to publish this article. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

CRediT authorship contribution statement

Xiangrui Yu: Writing – original draft, Visualization, Methodology, Investigation, Formal analysis, Data curation. Xiangyu Fei: Writing – original draft, Methodology, Investigation, Formal analysis, Data curation. Yanwen Bai: Validation, Software, Investigation. Yalong Liu: Validation, Investigation. Zhenhan Li: Validation, Software. Jiameng Sun: Validation, Methodology. Guanhua Cheng: Supervision, Resources, Funding acquisition. Zhonghua Zhang: Writing – review & editing, Supervision, Resources, Project administration, Funding acquisition, Conceptualization.

Acknowledgements

We acknowledge the financial support from the National Natural Science Foundation of China [U23A20554, 52371158], Natural Science Foundation of Shandong Province [ZR2025ZD08], and the Taishan Scholar Foundation of Shandong Province [tstp20250502, tsqn202507084].

References

[1] L. Gan, M. Heggen, R. O’Malley, B. Theobald, P. Strasser, Understanding and controlling nanoporosity formation for improving the stability of bimetallic fuel cell catalysts, Nano Lett. 13 (2013) 1131-1138, doi: 10.1021/nl304488q.

[2] A. Wittstock, V. Zielasek, J. Biener, C.M. Friend, M. Baumer, Nanoporous gold catalysts for selective gas-phase oxidative coupling of methanol at low temperature, Science 327 (2010) 319-322, doi: 10.1126/science.1183591.

[3] J. Zhang, C.M. Li, Nanoporous metals: Fabrication strategies and advanced electrochemical applications in catalysis, sensing and energy systems, Chem. Soc. Rev. 41 (2012) 7016-7031, doi: 10.1039/c2cs35210a.

[4] S.O. Kucheyev, J.R. Hayes, J. Biener, T. Huser, C.E. Talley, A.V. Hamza, Surface-enhanced raman scattering on nanoporous Au, Appl. Phys. Lett. 89 (2006) 053102, doi: 10.1063/1.2260828.

[5] L.H. Qian, X.Q. Yan, T. Fujita, A. Inoue, M.W. Chen, Surface enhanced Raman scattering of nanoporous gold: Smaller pore sizes stronger enhancements, Appl. Phys. Lett. 90 (2007) 153120, doi: 10.1063/1.2722199.

[6] L. Zhang, X. Lang, A. Hirata, M. Chen, Wrinkled nanoporous gold films with ultrahigh surface-enhanced Raman scattering enhancement, ACS Nano 5 (2011) 4407-4413, doi: 10.1021/nn201443p.

[7] J. Biener, A. Wittstock, L.A. Zepeda-Ruiz, M.M. Biener, V. Zielasek, D. Kramer, R.N. Viswanath, J. Weissmuller, M. Baumer, A.V. Hamza, Surface-chemistry-driven actuation in nanoporous gold, Nat. Mater. 8 (2009) 47-51, doi: 10.1038/nmat2335.

[8] Y.G. Guo, J.S. Hu, L.J. Wan, Nanostructured materials for electrochemical energy conversion and storage devices, Adv. Mater. 20 (2008) 2878-2887, doi: 10.1002/adma.200800627.

[9] J. Sun, J. Shi, J. Xu, X. Chen, Z. Zhang, Z. Peng, Enhanced methanol electro-oxidation and oxygen reduction reaction performance of ultrafine nanoporous platinum-copper alloy: Experiment and density functional theory calculation, J. Power Sources 279 (2015) 334-344, doi: 10.1016/j.jpowsour.2015.01.025.

[10] S. Kondrat, C.R. Pérez, V. Presser, Y. Gogotsi, A.A. Kornyshev, Effect of pore size and its dispersity on the energy storage in nanoporous supercapacitors, Energy Environ. Sci. 5 (2012) 6474-6479, doi: 10.1039/c2ee03092f.

[11] X. Lang, A. Hirata, T. Fujita, M. Chen, Nanoporous metal/oxide hybrid electrodes for electrochemical supercapacitors, Nat. Nanotechnol. 6 (2011) 232-236, doi: 10.1038/nnano.2011.13.

[12] S.H. Moon, S.J. Kim, M.C. Kim, J.Y. So, J.E. Lee, Y.K. Shin, W.G. Bae, K.W. Park, Stress-relieved Si anode on a porous Cu current collector for high-performance lithium-ion batteries, Mater. Chem. Phys. 223 (2019) 152-156, doi: 10.1016/j.matchemphys.2018.10.042.

[13] C. Park, H. Yun, S. Park, Preparation and photocatalytic degradation of methylene blue dye under LED light for porous and non-porous Cu balls, Colloid Interface Sci. Commun. 46 (2022) 100553, doi: 10.1016/j.colcom.2021.100553.

[14] R. Kobatake, K. Doi, T. Kubo, Y. Makihara, Y. Oki, M. Yokoi, H. Umehara, K. Tsuga, Novel fabrication of porous titanium by a resin-impregnated titanium substitution technique for bone reconstruction, RSC Adv. 9 (2019) 1625-1631, doi: 10.1039/c8ra08744j.

[15] N. Kobayashi, T. Fujii, Y. Shimamura, Unidirectional titanium fiber-reinforced porous titanium with mechanical properties suitable for load-bearing biomaterials, J. Mech. Behav. Biomed. Mater. 151 (2024) 106388, doi: 10.1016/j.jmbbm.2024.106388.

[16] P. Wang, X. Liu, H. Wang, J. Cao, J. Qi, J. Feng, Negative thermal expansion Y₂Mo₃O₁₂ particles reinforced AgCuTi composite filler for brazing C_f/SiC and GH3536 , Mater. Charact. 185 (2022) 185, doi: 10.1016/j.matchar.2022.111754.

[17] E.L. Zhang, S. Fu, R.X. Wang, H.X. Li, Y. Liu, Z.Q. Ma, G.K. Liu, C.S. Zhu, G.W. Qin, D.F. Chen, Role of Cu element in biomedical metal alloy design, Rare Met. 38 (2019) 476-494, doi: 10.1007/s12598-019-01245-y.

[18] T. Chen, D. Cheng, Y. Tai, F. Jing, H. Sun, D. Xie, Y. Leng, N. Huang, Y. Ken, Characterization of Ti-Cu films deposited by HPPMS and effect on NO catalytic release and platelet adhesion behavior, J. Wuhan Univ. Technol. Mater. Sci. Ed. 33 (2018) 505-511, doi: 10.1007/s11595-018-1852-5.

[19] S.Y. Li, J.L. Song, H. Wei, H.Y. Du, Y.H. Wei, L.F. Hou, Corrosion behavior of Cu-Ti alloy in simulated S^2- contaminated seawater , Rare Met. Mater. Eng. 51 (2022) 895-905, doi: 10.12442/j.issn.1002-185X.20210246.

[20] Z. Yan, S. Zhang, L. Ren, X. Bai, K. Yang, X. Wei, Anodic etching surface treatment and antibacterial properties of Ti-Cu, Acta Metall. Sinica 37 (2024) 1767-1776, doi: 10.1007/s40195-024-01734-9.

[21] S. Parida, D. Kramer, C.A. Volkert, H. Rosner, J. Erlebacher, J. Weissmuller, Volume change during the formation of nanoporous gold by dealloying, Phys. Rev. Lett. 97 (2006) 035504, doi: 10.1103/PhysRevLett.97.035504.

[22] T. Fujita, L.H. Qian, K. Inoke, J. Erlebacher, M.W. Chen, Three-dimensional morphology of nanoporous gold, Appl. Phys. Lett. 92 (2008) 251902, doi: 10.1063/1.2948902.

[23] F. Li, S. Luo, F. Qu, D. Wang, C. Li, X. Liu, Electrochemical dealloying preparation and morphology evolution of nanoporous Au with enhanced SERS activity, Coatings 13 (2023) 489, doi: 10.3390/coatings13030489.

[24] T. Wada, K. Yubuta, A. Inoue, H. Kato, Dealloying by metallic melt, Mater. Lett. 65 (2011) 1076-1078, doi: 10.1016/j.matlet.2011.01.054.

[25] Z. Lu, C. Li, J. Han, F. Zhang, P. Liu, H. Wang, Z. Wang, C. Cheng, L. Chen, A. Hirata, T. Fujita, J. Erlebacher, M. Chen, Three-dimensional bicontinuous nanoporous materials by vapor phase dealloying, Nat. Commun. 9 (2018) 276, doi: 10.1038/s41467-017-02167-y.

[26] J. Han, C. Li, Z. Lu, H. Wang, Z. Wang, K. Watanabe, M. Chen, Vapor phase dealloying: a versatile approach for fabricating 3D porous materials, Acta Mater. 163 (2019) 161-172, doi: 10.1016/j.actamat.2018.10.012.

[27] Z. Lu, F. Zhang, D. Wei, J. Han, Y. Xia, J. Jiang, M. Zhong, A. Hirata, K. Watanabe, A. Karma, J. Erlebacher, M. Chen, Vapor phase dealloying kinetics of MnZn alloys, Acta Mater. 212 (2021) 116916, doi: 10.1016/j.actamat.2021.116916.

[28] Y. Xia, Z. Lu, J. Han, F. Zhang, D. Wei, K. Watanabe, M. Chen, Bulk diffusion regulated nanopore formation during vapor phase dealloying of a Zn-Cu alloy, Acta Mater. 238 (2022) 118210, doi: 10.1016/j.actamat.2022.118210.

[29] Y. Liu, X. Jiao, P. Feng, Research progress of intermetallic compounds porous materials, Mater. China 36 (2017) 532-540, doi: 10.7502/j.issn.1674-3962.2017.07.06.

[30] J. Zhou, J. Zhu, W. He, Y. Cao, J. Pang, J. Ni, J. Zhang, Selective preferred orientation for high-performance antimony selenide thin-film solar cells via substrate surface modulation, J. Alloys Compd. 938 (2023) 168593, doi: 10.1016/j.jallcom.2022.168593.

[31] R.E. Hackenberg, The historical development of phase transformations understanding in ferrous alloys, in: E. Pereloma, D.V. Edmonds (Eds.), Phase Transformations in Steels, Woodhead Publishing, Cambridge, U.K, 2012, pp. 3-55.

[32] Z. Deng, K. Xu, Y. Tian, M. Lou, R. Xue, L. Zhang, L. Liu, K. Chang, Experimental investigation and thermodynamic re-assessment of the Ti-Zn system and atomic mobility of its bcc phase, Calphad. 76 (2022) 102392, doi: 10.1016/j.calphad.2022.102392.

[33] K. Doi, S. Ono, H. Ohtani, M. Hasebe, Thermodynamic study of the phase equilibria in the Sn-Ti-Zn ternary system, J. Phase Equilib. Diffus. 27 (2006) 63-74, doi: 10.1361/105497106x92826.

[34] Y. Tang, J. Ma, D. Han, J. Wang, H. Qi, L. Jin, Critical evaluation and thermodynamic optimization of the Cu-Zn, Cu-Se and Zn-Se binary systems, Metals 12 (2022) 1401, doi: 10.3390/met12091401.

[35] A.D. Laksono, C.M. Chen, Y.W. Yen, Interfacial reactions in the Sn-9.0 wt.% Zn/Cu-Ti alloy (C1990 HP) couple, Soldering Surf. Mount. Technol. 36 (2023) 30-38, doi: 10.1108/SSMT-05-2023-0027.

[36] Y. Zhuang, Z. Zou, B. Lu, Y. Li, D. Wang, M. Avdeev, S. Shi, Understanding the Li diffusion mechanism and positive effect of current collector volume expansion in anode free batteries, Chin. Phys. B 29 (2020) 068202, doi: 10.1088/1674-1056/ab943c.

[37] Y. Tanaka, M. Kajihara, Y. Watanabe, Growth behavior of compound layers during reactive diffusion between solid Cu and liquid Al, Mater. Sci. Eng. A 445-446 (2007) 355-363, doi: 10.1016/j.msea.2006.09.047.

[38] S. Park, Y. Kim, S.E. Kim, Low-temperature diffusion behavior of Ti in Cu/Ti-Ti/Cu bonding, J. Electron. Mater. 51 (2022) 2617-2623, doi: 10.1007/s11664-022-09501-1.

[39] Y. Wei, L. Zhu, Y. Li, Y. Chen, B. Guo, Formation mechanism and microstructure evolution of Cu/Ti diffusion bonding interface and its influence on joint properties, Vacuum 213 (2023) 112167, doi: 10.1016/j.vacuum.2023.112167.

[40] C.P. Wang, Y.S. Luo, Y. Lu, J.J. Han, Z. Shi, Y.H. Guo, X.J. Liu, Interdiffusion and atomic mobilities in bcc Ti-Ga and Ti-Cu alloys, J. Phase Equilib. Diffus. 38 (2017) 84-93, doi: 10.1007/s11669-016-0506-7.

[41] L. Vitos, A.V. Ruban, H.L. Skriver, J. Kollár, The surface energy of metals, Surf. Sci. 411 (1998) 186-202, doi: 10.1016/S0039-6028(98)00363-X.

[42] X. Wang, L. Ying, Y. Li, Q. Chen, J. Han, Y. Zeng, H. Du, Y. Gao, F. Huang, M. Chen, P. Liu, Atomic-scale dynamics of a bulk-diffusion-driven nonconservative phase transformation in vapor-phase dealloying, Matter 9 (2026) 102601, doi: 10.1016/j.matt.2025.102601.