{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,14]],"date-time":"2026-09-14T16:04:28Z","timestamp":1789401868929,"version":"build-2803163510"},"reference-count":26,"publisher":"MDPI AG","issue":"18","license":[{"start":{"date-parts":[[2026,9,14]],"date-time":"2026-09-14T00:00:00Z","timestamp":1789344000000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Ministry of Science and Higher Education of the Republic of Kazakhstan","award":["BR24992864"],"award-info":[{"award-number":["BR24992864"]}]},{"award":["BR24992864"],"award-info":[{"award-number":["BR24992864"]}],"id":[{"id":"https:\/\/ror.org\/05tyne317","id-type":"ROR","asserted-by":"publisher"}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>This study investigates the effects of applied voltage and treatment duration during electrolytic-plasma hardening (EPH) on the microstructure, phase composition, hardness, surface condition, and tribological behavior of 20X steel. EPH was performed in a 12 wt.% Na2CO3 aqueous electrolyte at voltages of 280, 300, and 320 V for 4 and 6 s. Scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray diffraction, instrumented indentation, surface profilometry, and ball-on-disk tribological testing were used to characterize the treated specimens. The 280 V\/4 s, 300 V\/4 s, 320 V\/4 s, and 280 V\/6 s conditions produced thermally modified surface layers without visible surface damage, whereas treatment at 300 and 320 V for 6 s resulted in localized surface melting. Among the undamaged specimens, the highest hardness was obtained at 280 V, reaching 329.6 \u00b1 15.8 HV after 4 s and 332.1 \u00b1 26.3 HV after 6 s, corresponding to an approximately 1.83\u20131.85-fold increase relative to the initial value of 180 HV. XRD revealed a predominantly \u03b1-Fe-based matrix, while weak secondary reflections could not be assigned reliably to specific phases. The minimum steady-state coefficient of friction was obtained at 300 V\/4 s (0.444 \u00b1 0.054), whereas the narrowest wear track was observed at 320 V\/4 s (379.48 \u00b1 36.24 \u03bcm). No direct correlation was found between hardness and tribological response, indicating that surface roughness and microstructural state should also be considered when selecting treatment parameters. The results define a stable EPH processing window for 20X steel and demonstrate that parameter selection should be based on a combined assessment of surface integrity, hardness, and tribological performance.<\/jats:p>","DOI":"10.3390\/ma19183907","type":"journal-article","created":{"date-parts":[[2026,9,14]],"date-time":"2026-09-14T15:19:04Z","timestamp":1789399144000},"page":"3907","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":0,"title":["Effect of Electrolytic-Plasma Hardening Parameters on the Microstructure and Mechanical Behavior of 20X Steel"],"prefix":"10.3390","volume":"19","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-4623-4681","authenticated-orcid":false,"given":"Arystanbek","family":"Kussainov","sequence":"first","affiliation":[{"name":"International School of Engineering, D. Serikbayev East Kazakhstan Technical University, Ust-Kamenogorsk 070010, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"formal-analysis","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0009-0001-8428-4033","authenticated-orcid":false,"given":"Zarina","family":"Aringozhina","sequence":"additional","affiliation":[{"name":"International School of Engineering, D. Serikbayev East Kazakhstan Technical University, Ust-Kamenogorsk 070010, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"methodology","vocabulary":"credit"}]},{"ORCID":"https:\/\/orcid.org\/0009-0008-2277-6666","authenticated-orcid":false,"given":"Gulnara","family":"Zhunissova","sequence":"additional","affiliation":[{"name":"International School of Engineering, D. Serikbayev East Kazakhstan Technical University, Ust-Kamenogorsk 070010, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"conceptualization","vocabulary":"credit"},{"role":"writing-original-draft","vocabulary":"credit"},{"role":"writing-review-editing","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"}]},{"given":"Lyaila","family":"Bayatanova","sequence":"additional","affiliation":[{"name":"International School of Engineering, D. Serikbayev East Kazakhstan Technical University, Ust-Kamenogorsk 070010, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"project-administration","vocabulary":"credit"},{"role":"funding-acquisition","vocabulary":"credit"},{"role":"visualization","vocabulary":"credit"}]},{"given":"Bauyrzhan","family":"Rakhadilov","sequence":"additional","affiliation":[{"name":"PlasmaScience LLP, Ust-Kamenogorsk 070000, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"project-administration","vocabulary":"credit"},{"role":"supervision","vocabulary":"credit"},{"role":"data-curation","vocabulary":"credit"}]},{"given":"Moldir","family":"Kaliaskarova","sequence":"additional","affiliation":[{"name":"International School of Engineering, D. Serikbayev East Kazakhstan Technical University, Ust-Kamenogorsk 070010, Kazakhstan"}],"role":[{"vocabulary":"crossref","role":"author"},{"role":"methodology","vocabulary":"credit"},{"role":"resources","vocabulary":"credit"},{"role":"investigation","vocabulary":"credit"},{"role":"formal-analysis","vocabulary":"credit"}]}],"member":"1968","published-online":{"date-parts":[[2026,9,14]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"2003739","DOI":"10.1002\/advs.202003739","article-title":"Recent Progress on Wear-Resistant Materials: Designs, Properties, and Applications","volume":"8","author":"Zhai","year":"2021","journal-title":"Adv. Sci."},{"key":"ref_2","doi-asserted-by":"crossref","unstructured":"Kombayev, K., Khoshnaw, F., Uazyrkhanova, G., and Moldabayeva, G. (2024). Experimental and Mathematical Modeling Investigation of Plasma Electrolytic Oxidation (PEO) for Surface Hardening of 20Ch Steel. 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