Rare earth phosphate based non reactive and non-wettable surfaces
OwnerSankar SASHIDHARAN, Rajesh KOMBAN +4inventors
InventorsSankar SASHIDHARAN, Rajesh KOMBAN, Abdul Azeez Peer MOHAMED, Solaiappan ANATHAKUMAR, Unnikrishnan Nair Saraswathy HAREESH, Krishna Gopakumar WARRIER
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Abstract
The present invention provides the use of lanthanum phosphate for creating non wetting, non-reactive surfaces for molten metals like zinc and aluminium. By virtue of this property, lanthanum phosphate finds extensive applications in metallurgical industry for metal casting.
Claims11
A metallophobic ceramic monolith made of nano rare-earth phosphates having density in the range of 96-99% (4.8-4.9 g/cc) of theoretical density for rendering a non-wetting and non-reactive surface to handle molten metals.
The metallophobic ceramic monolith as claimed in claim 4, wherein the metallic element is Aluminium, Silver or Zinc.
A process for making metallophobic ceramic monolith, made of nano rare-earth phosphates, having density in the range of 96-99% (4.8-4.9 g/cc) of theoretical density for rendering a non-wetting and non-reactive surface to handle molten metals, comprising the steps of
- (a) Spray granulating rare earth phosphate nanorods into granules of desired sizes in the range of 1 to 100μπι
- (b) Compaction processing of the above granules under uniaxial and isostatic load to obtain samples of green density of 45-55% Theoretical Density.
- (c) Coarsening the nanorods by high temperature calcination process and re-dispersion in aqueous medium with adequate binder to obtain a slurry having more than 70% solid
- loading and pouring them to porous moulds of varying shapes to obtain shaped monoliths having green density equal to 50% of theoretical density
- (d) Drying of samples obtained from 1(b) and 1(c) under controlled conditions (for e.g.:
- 45° C. and 75% RH) to obtain crack free specimens with minimum liquid content
- (e) High temperature treatment of above samples to obtain crack free monoliths of greater than 95% theoretical density.
A ceramic coating over crucibles or containers, obtained by coarsening rare earth phosphate nanorods by high temperature calcination process and re-dispersion in aqueous medium with adequate binder to obtain slurry having more than 70% solid loading and allowing it to heat treatment, so as to obtain non-wetting and non-reactive surfaces on heat treatment.
Dependencies are inferred from the claim text.