Electrodeposition of erosion-resistant titanium diboride coatings.
Flinn-DR; McCawley-FX; Smith-GR; Needham-PB Jr.
Avondale, MD: U.S. Department of the Interior, Bureau of Mines, RI 8332, 1979 Jan; :1-29
This Bureau of Mines report describes methods to electrodeposit erosion-resistant titanium diboride coatings from molten alkali metal borate baths at 900 deg c. These coatings have been shown to be highly resistant to material loss during impingement with high- velocity alumina and silicon carbide powders, and they show promise as protective coatings to reduce metal loss in erosive chemical environments, such as coal gasification systems. The most erosion- resistant coatings were prepared on nickel, inconel, and molybdenum from an electrolyte containing libo2, nabo2, na2tio3, and tio2. The best coatings were deposited at current densities of approximately or equal to 220 ma/cm2, using titanium or titanium diboride anodes. Erosion-resistant coatings were shown to exhibit (1) a high degree of crystallographic orientation along the (100) or (110) planes, (2) a chromium impurity level of less than 3 pct, and (3) a uniform, smooth, consolidated surface appearance when viewed under a microscope or by scanning electron microscopy. Optical spectroscopic studies of the molten electrolyte suggest that the lower valent (+3) titanium ion predominates in the baths.
Abrasion resistant coatings; Chemical properties; Electrodeposition; Erosion resistance; Hard surfacing; Inconel; Molten salt electrolytes; Molybdenum; Nickel; Nickel alloy Inconel; Physical properties; Protective coatings; Salt baths; Titanium boride
IH; Report of Investigations
NTIS Accession No.
Avondale, MD: U.S. Department of the Interior, Bureau of Mines, RI 8332