Synergistic effects of tubular halloysite clay and zirconium phosphate on thermal behavior of intumescent coating for structural steel

Zirconium phosphate (ZrP) recently introduced in intumescent fire protective coating has shown improvement in developing ceramic layer. The tubular halloysite clay (THC) due to its unique molecular structure can be combined with ZrP to enhance fire resistance by developing a strong silica network on the char surface. This study is aimed to investigate the synergistic effects of tubular halloysite clay and zirconium phosphate fillers to improve the thermal performance of the intumescent coating. The control coating formulation and a range of coating formulations using a combination of weight percentage of THC and ZrP were developed to study the influences of fillers on fire performance. The char expansion and fire resistance tests of the coatings were conducted using furnace fire test and Lab scale fire jet. Thermal stability of the coating was determined by TGA and char was characterized by FESEM, XRD, FTIR and XPS. Water-resistance test of the coating was performed according to ASTM D-870. Results showed that the reinforcement of THC-ZrP showed promising improvement on the performance of IFC and substrate temperature was far below the critical temperature, 550 °C. Sample HZ 5 showed the least backside steel substrate temperature of 219 °C. Expansion rate of char was found reduced with the addition of THC but improved the char compactness. The addition of THC and ZrP in IFC improved 18% fire resistance performance and 5% residual wt. Of char. Char morphology showed silica network, XRD and FTIR confirmed the presence of silicon. Water absorption test showed 95% less water absorption (HZ-5) compared to control coating. Post water immersion, fire test showed 7% increase in substrate temperature which is 18% less than control coating after water immersion fire test.The research was financially supported under the Minister of Higher Education (MOHE), Grant No. FRGS/1/2019/TK05/UTP/01/1 under FRGS Scheme. Authors also acknowledge the laboratory support of Advanced and Functional Materials, Corrosion Research Centre, Universiti Teknologi PETRONAS, Malaysia.Peer ReviewedPostprint (published version

Direct Determination of Sulfur Species in Coals from the Argonne Premium Sample Program by Solid Sampling Electrothermal Vaporization Inductively Coupled Plasma Optical Emission Spectrometry

A new direct solid sampling method for speciation of sulfur in coals by electrothermal vaporization inductively coupled plasma optical emission spectrometry (ETV-ICP OES) is presented. On the basis of the controlled thermal decomposition of coal in an argon atmosphere, it is possible to determine the different sulfur species in addition to elemental sulfur in coals. For the assignment of the obtained peaks from the sulfur transient emission signal, several analytical techniques (reflected light microscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction) were used. The developed direct solid sampling method enables a good accuracy (relative standard deviation ≤ 6%), precision and was applied to determine the sulfur forms in the Argonne premium coals, varying in rank. The generated method is time- and cost-effective and well suited for the fast characterization of sulfur species in coal. It can be automated to a large extent and is applicable for process-accompanying analyses