Thermal spraying of ceramic materials
AssigneeSeram Coatings AS
InventorsNuria ESPALLARGAS, Fahmi MUBAROK
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Abstract
A process for thermally spraying metal oxide coated ceramic particles onto a substrate comprising: (i) obtaining a plurality of metal oxide coated particles of silicon carbide, silicon nitride, boron carbide or boron nitride; and (ii) thermally spraying the particles of step (I) onto a substrate.
Claims23
A process for thermally spraying metal oxide coated ceramic particles onto a substrate comprising:
- (I) obtaining a plurality of metal oxide coated particles of silicon carbide, silicon nitride, boron carbide or boron nitride;
- and
- (ii) thermally spraying the particles of step (I) onto a substrate.
A process for thermally spraying metal oxide coated ceramic particles onto a substrate comprising:
- (I) obtaining a plurality of metal salt coated particles of silicon carbide, silicon nitride, boron carbide or boron nitride, such as metal hydroxide and/or metal carbonate coated particles;
- (II) calcining and sintering the particles of step (I) so as to form a plurality of metal oxide coated particles of silicon carbide, silicon nitride, boron carbide or boron nitride;
- and
- (III) thermally spraying the particles of step (II) onto a substrate.
A process for thermally spraying metal oxide coated ceramic particles onto a substrate comprising:
- (I) obtaining a plurality of particles of silicon carbide, silicon nitride, boron carbide or boron nitride;
- (II) combining the particles of step (I) with at least one metal salt, such as two metal salts, in the presence of a weak acid or weak base so as to form a metal salt coating on said particles such as metal hydroxide and/or metal carbonate coated particles;
- (III) drying, such as spray drying, the particles of step (II);
- (IV) calcining and sintering the particles of step (III) so as to form a plurality of metal oxide coated particles of silicon carbide, silicon nitride, boron carbide or boron nitride;
- and
- (V) thermally spraying the particles of step (IV) onto a substrate.
A process as claimed in any preceding claim in which the particles are silicon carbide particles.
A process as claimed in any preceding claim in which the metal oxide coating is a eutectic, especially YAG.
A process as claimed in any preceding claim wherein the thermal spraying is effected using a detonation gun.
A process as claimed in any preceding claim wherein the weak base is urea, ammonia or a hydrogen carbonate, especially ammonium hydrogen carbonate and the weak acid is citric acid.
A process as claimed in any preceding claim in which the substrate is metallic.
A process as claimed in any preceding claim in which the metal oxide coating forms at least 10 wt % of the coated particle weight before the thermal spraying process.
A process as claimed in any preceding claim in which the particles are coated with a hydroxide and/or carbonate prior to calcination.
Use of metal oxide coated particles of silicon carbide, silicon nitride, boron carbide or boron nitride for thermally spraying onto a substrate.
Metal oxide coated particles of silicon carbide, silicon nitride, boron carbide or boron nitride wherein the amount of metal oxide is at least 10 wt % of the total weight of the particles.
A process for preparing metal oxide coated ceramic particles comprising:
- (I) obtaining a plurality of particles of silicon carbide, silicon nitride, boron carbide or boron nitride;
- (II) combining the particles of step (I) with at least one metal salt in the presence of a weak acid or a weak base;
- (III) drying, such as spray drying, the particles of step (II);
- and
- (IV) calcining and sintering the particles of step (III) so as to form a plurality of metal oxide coated particles of silicon carbide, silicon nitride, boron carbide or boron nitride.
Dependencies are inferred from the claim text.