The Self-Propagating High temperature Synthesis (SHS) is an engineering technique developed to synthesize high-grade ceramic materials such as refractory, ceramic matrix composites, intermetallic compounds, and functional grade materials. Because of its energy efficiency and low cost compared to the original technique, SHS is combined with centrifugal casting to synthesize composite material inside metal pipe to extend the pipe’s longevity. The synthesis starts with filling the premix powder of substrate into a metal pipe whose one end is closed with a piece of wood and the other end is closed a ring-shaped wood. Attach the metal pipe to the centrifugal casting machine with adjustable speed meter. Allow the machine to spin continuously for 1-2 minutes to initiate the coating, complete with ignition from one end of the pipe to start SHS reaction. Once the reaction is complete, gradually lower the speed level then shut the machine down. The metal pipe is now coated from the inside with the composite material.
Picture 1 The procedure of synthesizing composite material inside metal pipe by centrifugal technique via the Self-Propagating High Temperature Synthesis
Composite materials of interest include metal-based materials such as Fe-WB and Fe-TiB2. The synthetic composite system is a reinforced system (WB= 28.9 ±0.8 GPa (Chen Y., et al., 2011) and TiB2= 25.3 ± 1.8 GPa (Raju G.B., et al., 2009)) with high-level hardness. With this capacity, the coating should extend the longevity of the pipe. Moreover, in order to reduce cost, the research selected natural substrate including (Ilmenite, FeTiO3) and (Wolflamite, Fe(Mn)WO4) which are affordable compared to other types available in the market.
Synthesized composite coating from two different systems can clearly be divided into 2 layers (shown in picture 2). Coating synthesized from Wolflamite, Fe(Mn)WO4 shows first layer of Fe-WB and second layer of Fe-Al2O3 (shown in 2A). Coating synthesized from Ilmenite, FeTiO3 shows first layer of Fe-TiB2 and second layer of Fe-Al2O3 (shown in 2B).
Picture 2(A) Coating synthesized from Wolflamite, Fe(Mn)WO4 and (B) Coating synthesized from Ilmenite, FeTiO3