Monazite Coatings On Fibres: Ii, Coating Without Strength Degradation

Washed and unwashed rhabdophane sols were used to apply monazite coatings to 3M Nextel 720 and 610 fibres. This precursor was designed to minimize stress corrosion from gaseous decomposition products at high temperature. The coatings were heat-treated in-line at 900-1300 deg C, in air, using a continuous vertical coater with immiscible liquid displacement. Coatings were characterized by optical microscopy, SEM, and transmission electron microscopy. The sol was characterized with light-scattering and zeta-potential measurements. Precursor phase evolution was studied with differential thermal analysis/thermogravimetric analysis and X-ray diffractometry. The washed sol had a higher pH and lower weight loss than the unwashed sol.