Due to its effective performance, intumescent fire retardant coating (IFRC) is widely used by oil and gas industries as well as in processing and petrochemicals plants to protect metallic substrates from fire. The present work developed an epoxy based IFRC comprising phosphate, nitrogen, barium and boron containing flame-retardants. The product was reinforced with nano-titanium oxide and then examined for performance with a lab scale hydrocarbon fire test. Thermal analysis of the coating was evaluated using TGA and DTGA under nitrogen and oxygen environments. Further characterization studies included FESEM, EDS, FTIR, XRD and XRF to determine effects from nano titanium oxide on char's performance. Results indicated that a coating reinforced with 4.5 wt% of nano-TiO2 added residual weight to the coating and provided longer thermal protection time compared to conventional fire retardant coatings.

Particle shape of Nano-TiO2 examined by TEM.

A fire protection test assessed the effects of nano-titanium oxide on the coating's thermal efficiency. We used a lab-scale hydrocarbon fire test in a portable cylinder filled with Butane gas at a flow rate of 105 g/h with three thermocouples affixed to the uncoated side of the substrate. Data Loggers were attached to thermocouples to digitally display temperatures minute-by-minute. Before and after burning, samples were weighed and any change in weight percent was calculated.A Q50 Thermal Gravimetric Analyzer verified the coating's residual weight (Perkin Elmer). Samples were run in both nitrogen and oxygen atmospheres at a heating rate of 10 ° C/min within a temperature range of 30-800 ° C. Final plot was obtained using Origin Pro 8 software.The S8 TIGER high-end wavelength dispersive X-ray fluorescence (WDXRF, Bruker) verified the char's chemical composition using Helium.A PerkinElmer FT-IR Spectrum One spectrometer verified the presence of functional groups in the char. Char samples were mixed with KBr powder. Spectrum V5.3.0 software recorded the IR spectrum. Final plot was obtained using Origin Pro 8 software.

Temperature Thresholds: Steel's structural properties begin to decline above 400-450 ° C. The uncoated substrate reaches a final temperature >550 °C after 5 minutes.

Thermal Degradation and Char Formation: All formulations exhibit a similar rise in temperature initially due to the coating's thermal degradation and the formation of char from chemical reactions. Once char forms, it acts as a thermal barrier, reducing the rise in temperature of the underlying substrate.

Effect of Nano-Fillers: The addition of nano-filler reduces backside temperatures by possibly dispersing within the coating and augmenting diffusion paths for the escape of non-flammable gases.

Impact on Thermal Insulation: Different formulations show varying degrees of thermal insulation. F-4 demonstrates the lowest substrate temperature due to more appropriately dispersed nano particles, which produce uniform cross-linkages that strengthen the char and restrict the escape of non-flammable gases.

Anti-Oxidation Property: Nano particles enhance the coating's anti-oxidation property, preventing visible cracks in the char, which can allow heat penetration.

Time/temperature curve for intumescent coating formulations.

The findings indicate that in the medical industry, metallic implants face significant challenges related to poor corrosion resistance and mechanical properties. Although non-metallic implants have been explored for their superior biocompatibility, metallic materials remain preferred due to their toughness, durability, and strength. Surface modification techniques to improve metallic implants have limitations, as these implants are still prone to corrosion from non-uniform, porous surface coatings. Specifically, 316L stainless steel implants rely on a non-porous passive film to prevent oxidation and corrosion. The quality of this passive film depends on the choice of 316L stainless steel powder and the sintering parameters during the metal injection molding process. The alloy composition, particularly the proportions of molybdenum, chromium, and nickel, and the sintering conditions such as temperature, time, and atmosphere, significantly influence the film's effectiveness. Improper conditions can lead to pitting corrosion, where pits can propagate and cause implant failure due to low densification. Thus, higher densification through bimodal and tri-modal powder systems and optimized particle size distributions is crucial. However, the link between densification and the formation of the chromium oxide film needs more exploration. Further experimental research is required to optimize particle size distribution and to correlate sintering parameters, particle shape, and size with densification and corrosion resistance in powder mixtures.

Demand in Construction Sector: With structural steel being a fundamental material in construction due to its strength and efficiency, there's a constant demand for enhanced fire protection solutions. Flame retardant coatings offer a means to improve the fire resistance of structural steel, thereby enhancing safety standards in buildings, bridges, and other infrastructure projects.

Oil and Gas Industry: The oil and gas industry presents a lucrative market for flame retardant coatings due to the high-risk environment associated with hydrocarbon storage and transportation. The ability of these coatings to withstand high temperatures and provide extended protection can mitigate the risk of fire-related accidents, thereby safeguarding lives and assets.

Regulatory Compliance: Environmental regulations restricting the use of halogenated flame retardants drive the demand for alternative solutions that meet safety standards without posing environmental risks. Advanced coatings incorporating nano-fillers and non-toxic additives align with these regulatory requirements, enhancing their market acceptance.s

Microstructure of char, (a) outer surface of F-2, (b,c) outer surface of F-4 and (d) inner surface of F-4.