Key Performance Characteristics
- Excels in elevated temperature environments where fly ash and bed ash erosion occurs
- Superior bond strength without necessity of bond coat
- Excellent abrasion resistance
- Hardness increases as a function of time and temperature
SHS®8000W coatings exhibit excellent combinations of corrosion and wear resistance, superior bond strength and high impact resistance. Superior bond strength values signify that this material has exceptional adhesion and cohesion. This also highlights the material’s extremely low residual stress (even at high thicknesses) inherent in this coating type. The probability of “pull-out” of individual particles during wear, erosion and other service conditions is extremely low. Low coating permeability results in a highly corrosion resistant barrier. Low oxide content contributes to high bond strength due to the very limited presence of internal voids and other defects. These characteristics provide predictable coating performance across a broad variety of service environments. SHS8000W is especially resistant to elevated temperature oxidation, erosion and corrosion for protecting boiler tubes and LPA screens in coal fired boilers.
EXTREME ABRASION/EROSION RESISTANCE
SHS®8000W combines erosion with high hardness in elevated temperature environments where fly ash and bed ash erosion occurs. Based on results from aggressive accelerated elevated temperature erosion tests with highly erosive fly ash from a coal fired boiler at 30º and 90º impact angles, SHS®8000W coatings can provide increased lifetime over carbon steel substrate and leading industry standard protective coatings.
Impact testing on SHS®8000W coatings was performed using a Gardner Impact testing machine with a 12 lb. test weight and 0.5 in. diameter impact punch dropped from 40 in height. As-sprayed and heat-treated (one hour soak at 600º C, water quenched) coatings of 0.020 in. thickness were tested. The as-sprayed and heat-treated coatings survived 480 in-lbs impact and demonstrated the ability to deform with the substrate without chipping, cracking or delaminating.
When SHS®8000W is sprayed directly onto substrate alloys using conventional twin wire thermal spray equipment and standard substrate preparation practices, and without a bond coat, extremely high bond strength is achieved. In ASTM C633-01 Adhesion/Cohesion Bond Strength Tests, extremely high bond strength is achieved for SHS8000W coatings on plain carbon steel, far exceeding bond strength of conventional coating materials.