NASA Technical Reports Server (NTRS) : Characterization pdf

NASA Technical Reports Server (NTRS) : Characterization

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A coating composed of 77 wt % CaF2 – 23 wt % LiF fused on IN-750 nickel-based alloy was studied using SEM, XRD, EDX, and optical microscopic methods. The surfaces examined were the as-fused coating with no subsequent treatment, the coating after ultrasonic cleaning in water, and the uncoated polished and etched metal. It was found that the coating reacts during fusion with Ti and Nb rich inclusions in the alloy. Numerous small rectangular crystallites of Ca(Ti,Nb) oxide are formed beneath an overlay of fused fluoride composition. These crystallines are stubby and appear to be embedded in the metal substrate surface. It is known from previous studies that this coating-alloy system has good tribological properties in extreme conditions, such as liquid fluorine. It has been concluded from the present study that the short firmly embedded crystalline protuberances contribute to the coating adherence and thereby to enhanced coating wear life

• Creator/s: NASA Technical Reports Server (NTRS
• Date: 6/1/1986
• Year: 1986
• Book Topics/Themes: NASA Technical Reports Server (NTRS), CALCIUM FLUORIDES, CRYSTALLITES, NICKEL ALLOYS, NIOBIUM, PROTECTIVE COATINGS, TITANIUM, TRIBOLOGY, CRYSTAL SURFACES, ELECTRON MICROSCOPY, X RAY DIFFRACTION, Deadmore, D. L., Sliney, H. E

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