effect of basalt fibres reinforcement and aluminum trihydrate on the thermal properties of intumescent fire retardant coatings

This research is carried out in order to study the synergistic effect of aluminium trihydrate and basalt fibres on the properties of fire resistant intumescent coatings. Intumescent fire retardant coatings were developed using different flame retardants such as ammonium polyphosphate, expandable graphite, melamine and boric acid. These flame retardants were bound together with the help of epoxy binder along with curing agent. Furthermore, individual and combinations of aluminium trihydrate and basalt fibres was incorporated in the formulations to analyse mechanical and chemical properties of the coatings. Char expansion was observed using furnace test, thermogravimetric analysis was used to determine residual weight, X-Ray Diffraction was performed to investigate compounds present in the char, shear test was conducted to determine char strength and scanning electron microscopy analysis was performed to observe morphology of the burnt char. From the microscopic investigation it was concluded that the dense structure of the char increased the char integrity by adding basalt and aluminium trihydrate as fillers. X-Ray Diffraction results shows the presence boron phosphate, and boric acid which enhanced the thermal performance of the coating up to 800°C. From the Thermogravimetric analysis it was concluded that the residual weight of the char was increased up to 34.9 % for IC-B2A4 which enhanced thermal performance of intumescent coating

DEVELOPMENT OF MINERAL AND CARBON FIBRES REINFORCED INTUMESCENT COATINGS FOR STEEL STRUCTURES

A range of intumescent coatings (IC) are in practice for fire protection as fire posed great threats to human and buildings. However, low performance and soft char of these coatings make them less effective. In this research, control IC formulation was developed using ammonium polyphosphate, pentaerythritol, melamine at 3:1:1 ratio, and nine intumescent fillers. Epoxy to hardener ratio of 2: I was found to provide better char qualities and thermal performance. Boric acid at 12.66 wt% enhanced thermal performance of IC, improved char qualities and adhesion to the substrate. Compared to a market coating, the control developed higher expansion with more residues in 800°C furnace fire test (FFT). TGA analysis confirmed its better thermal stability and higher residual weight. The control formulation was reinforced with fibres for improvement of fire performance and char strength

Effect of Grain Boundary Formation in Microstructural Changes in IN 738 Service Exposed Turbine Blade

Microstructural changes on a Nickel based superalloy service exposed gas turbine blade after 52,000 hours at 720°C temperature was investigated. The study examines the grain boundary growth sizes; the changes with respect to gamma prime (γi) precipitate and phase distributions that occurred during operation. In order to observe the changes some different portions of the turbine blade undergone scanning electron microscope (SEM) to determine the grain size measurement and the EDX was used to evaluate the elemental analysis. The grain growths were discrete in formation along the grain boundary (GB) and little difference in the size of (γi) precipitates existed in different locations. The gradual transition of grain boundary-carbide morphology from the original fine discrete to fine semi-continuous, continuous film-like and finally coarse is observed in the specimens. The changes mostly evolves around two distinct phases which is from the solid to the equilibrium (sigma coarse phase) and then back to the solid (hardening gamma prime precipitate) phase. The grain size of (γi) precipitate varies throughout the surface of the turbine blade and there is a significant difference between the leading and trailing edge. The microstructural changes on the serviced blade can be interpreted to indicate that no obvious microstructural degradation and phase deformation occurred during exposure time

Effect of Grain Boundary Formation in Microstructural Changes in IN 738 Service Exposed Turbine Blade

Microstructural changes on a Nickel based superalloy service exposed gas turbine blade after 52,000 hours at 720°C temperature was investigated. The study examines the grain boundary growth sizes; the changes with respect to gamma prime (γi) precipitate and phase distributions that occurred during operation. In order to observe the changes some different portions of the turbine blade undergone scanning electron microscope (SEM) to determine the grain size measurement and the EDX was used to evaluate the elemental analysis. The grain growths were discrete in formation along the grain boundary (GB) and little difference in the size of (γi) precipitates existed in different locations. The gradual transition of grain boundary-carbide morphology from the original fine discrete to fine semi-continuous, continuous film-like and finally coarse is observed in the specimens. The changes mostly evolves around two distinct phases which is from the solid to the equilibrium (sigma coarse phase) and then back to the solid (hardening gamma prime precipitate) phase. The grain size of (γi) precipitate varies throughout the surface of the turbine blade and there is a significant difference between the leading and trailing edge. The microstructural changes on the serviced blade can be interpreted to indicate that no obvious microstructural degradation and phase deformation occurred during exposure time