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US 6,413,589 B1Granted
Ceramic coating method
OwnerChou H. Liinventor
Life of this patent
Estimating the term…
Abstract
A method of coating a ceramic and bonding ceramic onto a substrate for practical uses over 630° C. includes forming a brazed bonding layer at a contact area between the ceramic and the substrate by a fluidic reaction and causing the bonding layer to wet both the ceramic and substrate with a wetting angle of 0-5° to thereby coat and bond the ceramic onto bond the substrate over the entire contact area with a continuous, essentially 100% dense bonding layer. The bonding layer is so free of bonding defects that the resulting bonded product can withstand repeated thermal shocks by quenching in 0° ice water from a temperature in the range of 630-980° C.
Claims30
A method of uniformly coating a ceramic onto a substrate to form a ceramic coated product, comprising the steps of:
- providing said substrate which is selected from the group consisting of a metal and a ceramic;
- providing said ceramic at a selected contact region of said substrate;
- providing at said contact region a ceramic coating composition which forms a liquid ceramic coating layer that wets and bonds said ceramic and said substrate when heated to an elevated ceramic coating temperature of over 800° C.;
- without pressing or sintering heating said ceramic together with said substrate and said ceramic coating composition to the elevated ceramic coating temperature forming said liquid ceramic coating layer;
- and
- solidifying said liquid ceramic coating layer at said contact region into a solid ceramic coating layer uniformly and solidly bonding said ceramic to said substrate thereby producing said ceramic coated product;
- said solid ceramic coating layer having such a uniform composition and microstructure as to contain no voids between said ceramic, said substrate visible at a magnification of up to 1000X and is thermodynamically stable at temperatures above 630° C.
4 more elements
The method of coating a ceramic onto a substrate comprising;
- supplying said ceramic;
- selecting a metal or ceramic substrate having a top major surface;
- preparing a ceramic coating composition containing a material chemically reactive to said ceramic;
- causing said ceramic coating composition to contact at least one of said substrate and said ceramic;
- heating the substrate, ceramic, and ceramic coating composition to an elevated temperature of over 800° C. without externally applied pressure to form on said substrate a metallizing fluid ceramic coating layer comprising a material of said ceramic;
- said fluid ceramic coating layer, wetting and bonding by chemical reaction both said ceramic and said substrate at said elevated temperature;
- and
- including solidifying through a phase transformation said fluid ceramic coating layer into a solid ceramic coating layer which is sufficiently free of coating defects to withstand at least a plurality of thermal shocks by quenching to 0° C. water from a temperature of at least 630° C.
5 more elements
A method of uniformly coating onto a substrate mixed solid particles having different average densities and sizes and suspended in a common fluid suspension medium comprising:
- size-rationing said mixed solid particles having the different average densities and sizes in at least one calculated ratio to equalize, with an accuracy of better than 10 to 20%, average settling velocities of said mixed solid particles in said common fluid suspension medium at least in a preselected time period of the coating process, at least some of said mixed solid particles being non-metallic particles;
- suspending said mixed solid particles in said common fluid suspension medium to form a coating composition;
- applying said coating composition onto the substrate to form a substantially uniform coating of said mixed solid particles at least in the preselected time period of the coating process whereby said mixed solid particles come out of said fluid suspension medium in a substantially constant chemical composition ensuring uniformity and reproducibility of the coating results;
- and
- heating said substrate and the coating of said mixed solid particles suspension thereon to an elevated heat treatment temperature to form a uniformly coated mixed solid particles product.
2 more elements
A method of forming a uniform and continuous coated ceramic layer on a substrate, comprising;
- supplying a substrate;
- providing a plurality of ceramic particles on said substrate, one of said ceramic particles and substrate having a coefficient of thermal expansion which is over 100% higher than that of the other;
- forming said ceramic particles on said substrate in a layer form wherein neighboring ceramic particles have respective contact regions therebetween;
- providing at each of said contact regions a ceramic coating composition capable of forming a uniform and continuous fluid ceramic coating layer that fluidizes when heated to an elevated ceramic coating temperature of over 800° C.;
- without application of external pressure heating together said substrate, said ceramic particles and said ceramic coating composition to the elevated ceramic coating temperature forming said fluid ceramic coating layer which wets and bonds by chemical reaction said ceramic particles and said substrate at said respective contact regions;
- and
- solidifying through a phase transformation said fluid ceramic coating layer to produce a uniform and continuous solid coated ceramic layer on said substrate;
- said solid coated ceramic layer being thermally stable at a temperature of at least above 630° C.
5 more elements
A method of uniformly coating a plurality of ceramic particles onto a substrate to form a solid ceramic coated product wherein one of said substrate and said ceramic particles has a coefficient of thermal expansion which is at least 100% greater than that of the other, comprising the steps of:
- providing a substrate which is selected from the group consisting of a metal and a ceramic and having a contact region thereon;
- without application of external pressure, providing at said contact region a fluid ceramic coating composition capable of forming a fluid ceramic bonding layer positioned at least between said substrate and said ceramic particles when heated to an elevated ceramic coating temperature;
- heating said substrate, said ceramic particles, and said fluid ceramic coating composition to the elevated ceramic coating temperature forming said fluid ceramic bonding layer;
- said fluid ceramic layer, wetting by chemical reaction and not by plating or solid sintering under pressure, the plurality of said ceramic particles and said substrate to form a fluid ceramic coating layer;
- and
- solidifying through a phase transformation said fluid ceramic bonding layer into a solid ceramic coating layer thereby producing said solid ceramic coated product;
- said solid ceramic coating layer containing no voids or cracks visible at a magnification of up to 10000X, and being capable of withstanding a temperature of at least 630° C.
4 more elements
A method of making a heat-resistant article of manufacture formed of a ceramic and a substrate comprising the steps of:
- providing said ceramic;
- providing a substrate which is selected from the group consisting of a metal and a ceramic and having at a selected area thereon a contact region;
- providing at said contact region a ceramic coating composition which forms a fluid ceramic coating layer that is positioned at least between said ceramic and said substrate when heated to an elevated ceramic coating temperature;
- and
- heating without external pressure or sintering said ceramic together with said substrate and said ceramic coating composition to the elevated ceramic coating temperature forming said fluid ceramic coating layer which fluid diffusion bonds together through chemical reaction said ceramic and said substrate;
- solidifying through a phase transformation said fluid diffusion bonded substrate-ceramic assembly to produce a solid ceramic coated article;
- said ceramic coating layer containing no voids or cracks visible at a magnification of up to 1000× said ceramic coating layer and being sufficiently free of coating defects to retain coating integrity despite a plurality of thermal shocks by quenching from a temperature of at least 630° C. whereby said solid ceramic coated article of manufacture can also withstand temperatures above 630° C.
4 more elements
Dependencies are inferred from the claim text.