Abstract In present research work, the effect of nano-sized boron nitride (BN) was studied on intumescent fire retardant coating (IFRC) for structural application. The coated steel substrates were subjected to furnace fire test at 800 °C for 2 h and fire protection test for 1 h. The coatings were characterized by Thermogravimetric analysis (TGA) while the char from fire test was characterized by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Furnace fire test showed that IFRC reinforced with 4 mass% of nano-sized BN expanded more than 54.84% compared to the BN-1 formulation. Fire protection test performed for 1 h showed minimum substrate temperature of 140 °C with 4 mass% of BN which proved that the IFRC can successfully protect steel substrates within its critical temperature. A maximum of 44.49% residual mass was also recorded for the same coating. XRD analysis revealed that the remaining char contained boron phosphate, boron nitride and phosphoric nitride which are stable at high temperature. The presence of these compounds was also confirmed by functional group analysis using FTIR. FESEM confirmed that micrograph of char contained hexagonal BN. XPS analysis showed a fraction decrease in carbon contents of char residues of intumescent coating formulations with the increase of BN quantity. Pyrolysis GC–MS confirmed that formulations BN-4 released less gaseous product concentration compared to BN-1. Water immersion test showed that there was no trend of mass gain percentage with increasing amount of nano-sized boron nitride incorporated into the coating. The mass gain remained between 1.74% to 2.82%. Overall concluded that the formulation with 4 mass% BN effectively promoted the amount of char acted as a passive protective layer to the substrate resulting in lower substrate temperature with higher coating residual mass.

中文翻译：

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纳米氮化硼对环氧膨胀型涂料热分解及耐水性能的影响

摘要 在目前的研究工作中，研究了纳米尺寸的氮化硼（BN）对结构应用的膨胀型防火涂料（IFRC）的影响。涂层钢基材在 800℃下进行 2 小时的炉火试验和 1 小时的防火试验。通过热重分析 (TGA) 对涂层进行表征，而通过场发射扫描电子显微镜 (FESEM)、X 射线衍射 (XRD)、傅里叶变换红外光谱 (FT-IR) 和 X 射线光电子学表征燃烧试验的炭光谱（XPS）。炉火试验表明，与 BN-1 配方相比，用 4 质量％的纳米尺寸 BN 增强的 IFRC 膨胀超过 54.84％。进行 1 小时的防火测试表明，在 4 质量％的 BN 下，最低基材温度为 140 °C，这证明 IFRC 可以在其临界温度内成功保护钢基材。对于相同的涂层，还记录到最大 44.49% 的残留质量。XRD分析表明，剩余的焦炭含有在高温下稳定的磷酸硼、氮化硼和氮化磷。这些化合物的存在也通过使用 FTIR 的官能团分析得到证实。FESEM 证实炭的显微照片包含六方氮化硼。XPS 分析表明，随着 BN 量的增加，膨胀型涂料配方的焦炭残留物的碳含量会有所下降。热解 GC-MS 证实，与 BN-1 相比，配方 BN-4 释放的气态产物浓度更低。水浸试验表明，随着纳米氮化硼掺入量的增加，质量百分比没有增加的趋势。质量增加保持在 1.74% 至 2.82% 之间。总体得出结论，含 4 质量％ BN 的配方有效地促进了作为钝化保护层的炭对基材的量，从而导致较低的基材温度和较高的涂层残余质量。