HVOF coatings for heavy wear, high impact applications

Conference · Sat Dec 31 04:00:00 EST 1994

OSTI ID:115537

Moskowitz, L

A-4 aircraft are used extensively for carrier training. The hook point used for grabbing the cable that arrests the aircraft during a carrier landing is relatively expensive to manufacture and can only be produced by a limited number of qualified vendors. For training, the aircraft lands on a concrete runway, then drags the hook for 100 to 1500 feet. A wear-resistant coating on the bottom of the hook point was desired to extend the life of parts used for training, especially if the coating could be reapplied several times. The coating sought had to be capable of withstanding the impact sustained when the hook point contacted the ground while moving at greater than 100 MPH, then survive the wear of rubbing across 1000 feet of concrete while moving at these speeds. A further restriction was that the coating had to be applied to an alloy steel heat treated to a hardness of RC 47--50, especially for recoat applications. Coating materials were selected on the basis of finding a material considered tough enough to withstand the initial impact, then hard enough to provide the wear resistance needed. It was felt that increased hardness and increased thickness would lower the ability to withstand impact, while increasing the ability to withstand the severe rubbing wear. Coating candidates included NiCrB systems at two hardnesses, each sprayed to three different thicknesses, 25%NiCr-CrC and Colmonoy 88A were selected for high hardness in a ductile matrix, Stellite compositions varying in as-sprayed hardness because of their ability to provide wear resistance by work hardening, molybdenum and Tribaloy for possible reduced friction, and an amorphous FeNiB alloy applied with twin arc wire. The coatings were first screened with simulated tests involving a drop weight for impact resistance and a spinning concrete wheel test developed by Dayton T. Brown Co. for wear resistance.

• OSTI ID: 115537
• Report Number(s): CONF-9404233--
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AIRCRAFT COMPONENTS
CHROMIUM
CHROMIUM CARBIDES
FLAME SPRAYING
IMPACT STRENGTH
NICKEL
PROTECTIVE COATINGS
SPRAY COATING
SPRAYED COATINGS
THICKNESS
WEAR RESISTANCE