Magnesium oxide type building boards are a relatively new alternative to traditional sheeting materials such as plywood, gypsum plasterboard and fibre-cement board. They have many advantages; strength, lightweight, ease of use and excellent fire resistance, which has become increasingly important as demanded by industry and required by more stringent legislation. Recently cases of durability issues associated with magnesium oxychloride boards in Denmark have emerged, however the precise nature of the problem was not established. These issues have been related to magnesium oxychloride boards which were exposed to high levels of moisture. In this paper the mechanism of the failures observed in Denmark has been investigated. The difference in quality between various magnesium oxychloride boards available in the market was also studied. It was found that there are significant differences, both physically and chemically, between magnesium oxychloride boards supplied from different manufacturers. Crucially, the performance of each board when exposed to high levels of relative humidity was vastly different. Some of the boards investigated displayed behaviour similar to that observed in Denmark, whilst other boards exhibited substantial resistance to humid environments and had not deteriorated after 60 weeks of exposure.

中文翻译：

---

氯氧化镁板：了解一种新型建筑材料

氧化镁型建筑板是传统板材（如胶合板、石膏石膏板和纤维水泥板）的一种相对较新的替代品。它们有很多优点；强度、重量轻、易于使用和出色的耐火性，这在工业要求和更严格的立法要求下变得越来越重要。最近在丹麦出现了与氯氧化镁板相关的耐久性问题的案例，但问题的确切性质尚未确定。这些问题与暴露在高湿度环境中的氯氧化镁板有关。在本文中，研究了在丹麦观察到的故障机制。还研究了市场上可用的各种氯氧化镁板之间的质量差异。结果发现，不同制造商提供的氯氧化镁板在物理和化学方面存在显着差异。至关重要的是，当暴露在高相对湿度下时，每块电路板的性能大不相同。一些被调查的板表现出与在丹麦观察到的相似的行为，而其他板表现出对潮湿环境的显着抵抗力，并且在暴露 60 周后没有变质。