{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,25]],"date-time":"2026-09-25T20:11:39Z","timestamp":1790367099915,"version":"4.1.0"},"reference-count":27,"publisher":"MDPI AG","issue":"17","license":[{"start":{"date-parts":[[2023,8,30]],"date-time":"2023-08-30T00:00:00Z","timestamp":1693353600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"name":"Qinghai Minzu University","award":["2022TQ03"],"award-info":[{"award-number":["2022TQ03"]}]},{"name":"Qinghai Minzu University","award":["2021-ZJ-737"],"award-info":[{"award-number":["2021-ZJ-737"]}]},{"name":"\u201cKunlun Talents High-end Innovation and Entrepreneurship Talents\u201d of Qinghai Province","award":["2022TQ03"],"award-info":[{"award-number":["2022TQ03"]}]},{"name":"\u201cKunlun Talents High-end Innovation and Entrepreneurship Talents\u201d of Qinghai Province","award":["2021-ZJ-737"],"award-info":[{"award-number":["2021-ZJ-737"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Materials"],"abstract":"<jats:p>The deterioration process and deterioration mechanism of magnesium oxychloride cement (MOC) in an alkaline environment were studied using a scanning electron microscope (SEM), an X-ray diffractometer (XRD), a Fourier transform infrared spectrometer (FT-IR) and a micro-electro-hydraulic servo pressure testing machine to investigate the effects of soaking time in 10 wt.% NaOH solution on the macro- and micro-morphology, phase composition and compressive strength of MOC samples. The results show that the deterioration of MOC samples under an alkaline environment is mainly caused by the alkaline environment providing more OH\u2212 ions, which can react with 5Mg(OH)2\u00b7MgCl2\u00b78H2O (P 5) in the sample. The resulting reaction gives rise to a faster decomposition of 5Mg(OH)2\u00b7MgCl2\u00b78H2O (P 5) and a substantial reduction in the strength of the sample, and finally leads to a gradual deterioration of MOC samples. Meanwhile, immersion time exhibits a significant effect on MOC samples. The extension of immersion time coincides with more OH\u2212 ions entering the sample, and the greater presence of OH ions increases the likelihood that more P 5 will produce a hydrolysis reaction, further resulting in the increased deterioration of the sample. After soaking for 6 h in alkaline media, the main phase composition of the surface layer of an MOC sample changes to MgO and Mg(OH)2, and its microscopic morphology is also dominated by round sheets, giving rise to a sharp decrease in its compressive strength (52.2%). When the immersion time is prolonged to 72 h, OH\u2212 ions have already immersed into the inner core of the sample, causing the disappearance of P 5 from the whole sample. At the same time, both the surface and inner core of the sample exhibit a disc-shaped morphology, and chalking phenomena also appear on the surface of the sample. This reduces the compressive strength of the sample to 13.5 MPa, only 20% of its compressive strength in water. The compressive strength of the sample after 120 h of immersion is as low as 8.6 MPa, which is lower than that of the sample dipped in water for 21 days (9.5 MPa). As a result, the MOC samples studied in alkaline environments exhibit a faster deterioration rate, mainly because of a faster hydrolysis reaction by P 5, caused by more OH\u2212 ions.<\/jats:p>","DOI":"10.3390\/ma16175924","type":"journal-article","created":{"date-parts":[[2023,8,30]],"date-time":"2023-08-30T10:30:52Z","timestamp":1693391452000},"page":"5924","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":10,"title":["Study on the Deterioration Mechanism of Magnesium Oxychloride Cement under an Alkaline Environment"],"prefix":"10.3390","volume":"16","author":[{"given":"Lingyun","family":"An","sequence":"first","affiliation":[{"name":"Qinghai Provincial Key Laboratory of Nanomaterials and Technology, College of Physics and Electronic Information Engineering, Qinghai Minzu University, Xining 810007, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2936-7255","authenticated-orcid":false,"given":"Chenggong","family":"Chang","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China"},{"name":"Key Laboratory of Comprehensive and Highly Efficient Utilization of Salt Lake Resources, Qinghai Institute of Salt Lake, Chinese Academy of Sciences, Xining 810008, China"},{"name":"Key Laboratory of Salt Lake Resources Chemistry of Qinghai Province, Xining 810008, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-8345-5929","authenticated-orcid":false,"given":"Fengyun","family":"Yan","sequence":"additional","affiliation":[{"name":"State Key Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jianhong","family":"Peng","sequence":"additional","affiliation":[{"name":"Qinghai Provincial Key Laboratory of Nanomaterials and Technology, College of Physics and Electronic Information Engineering, Qinghai Minzu University, Xining 810007, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2023,8,30]]},"reference":[{"key":"ref_1","unstructured":"Qinghai Institute of Salt Lake, Chinese Academy of Sciences (2015). 60 Years of Salt Lake Research of Chinese Academy of Science, Science Press."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"371","DOI":"10.1680\/jadcr.18.00174","article-title":"Long-term mechanical properties and micro mechanism of magnesium oxychloride cement concrete","volume":"32","author":"Chang","year":"2020","journal-title":"Adv. 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