Process for depositing a composite ceramic coating on a cemented carbide substrate
First Claim
1. In a process for depositing a wear resistant ceramic coating on a cemented carbide substrate comprising the step of:
- passing over the cemented carbide substrate a first gaseous mixture of a first halide vapor selected from the group consisting of halides of aluminum, yttrium, and zirconium, with one or more volatile oxidizing gases, and optionally a carrier gas, at a temperature of about 900°
-1250°
C., at a pressure between about 1 torr and about ambient pressure, and at partial pressure ratios, at a flow rate, and for a time sufficient to deposit a continuous, fully dense, adherent, wear resistant layer of a material selected from the group consisting of oxides of aluminum, zirconium, and yttrium about 0.1-20 microns thick on the cemented carbide substrate;
the improvement which comprises the steps of;
mixing with the first gaseous mixture at least one additional vapor selected from the halides of aluminum, zirconium, and yttrium;
wherein the additional vapor is different from the first halide vapor, and is mixed at a partial pressure selected to form at least one discontinuous additional phase, dispersed as discrete particles within the continuous oxide layer, of at least one material selected from the group consisting of oxides of aluminum, zirconium, and ytrrium, to form a wear resistant composite ceramic layer on the cemented carbide substrate.
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Accused Products
Abstract
A process for producing a wear resistant article, such as a cutting tool. Gaseous halides of two or more of aluminum, zirconium, and yttrium with other reactants are passed over a cemented carbide substrate at 900°-1250° C. and 1 torr to about ambient pressure to form a composite ceramic coating on the substrate. The coating is a continuous first-phase metal oxide matrix having particles of at least one different metal oxide dispersed therein. In a preferred process, one or more of the metal halides is pulsed into the gaseous mixture containing a different metal halide to control the deposition of the particles.
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Citations
22 Claims
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1. In a process for depositing a wear resistant ceramic coating on a cemented carbide substrate comprising the step of:
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passing over the cemented carbide substrate a first gaseous mixture of a first halide vapor selected from the group consisting of halides of aluminum, yttrium, and zirconium, with one or more volatile oxidizing gases, and optionally a carrier gas, at a temperature of about 900°
-1250°
C., at a pressure between about 1 torr and about ambient pressure, and at partial pressure ratios, at a flow rate, and for a time sufficient to deposit a continuous, fully dense, adherent, wear resistant layer of a material selected from the group consisting of oxides of aluminum, zirconium, and yttrium about 0.1-20 microns thick on the cemented carbide substrate;the improvement which comprises the steps of; mixing with the first gaseous mixture at least one additional vapor selected from the halides of aluminum, zirconium, and yttrium; wherein the additional vapor is different from the first halide vapor, and is mixed at a partial pressure selected to form at least one discontinuous additional phase, dispersed as discrete particles within the continuous oxide layer, of at least one material selected from the group consisting of oxides of aluminum, zirconium, and ytrrium, to form a wear resistant composite ceramic layer on the cemented carbide substrate. - View Dependent Claims (2)
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3. A process for depositing a wear resistant composite ceramic coating on a cemented carbide substrate comprising the steps of:
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passing over the cemented carbide substrate a first gaseous mixture of a first halide vapor selected from the group consisting of halides of aluminum, yttrium, and zirconium, with one or more volatile oxidizing gases, and optionally a carrier gas, at a temperature of about 900°
-1250°
C. at a pressure between 1 torr and about ambient pressure, wherein the one or more volatile oxidizing gases, the partial pressure ratios, the flow rates, and the deposition time are selected so that a continuous, fully dense, adherent, wear resistant first-phase layer of a material selected from the group consisting of oxides of aluminum, zirconium, and ytrrium about 0.1-20 microns thick is deposited on the cemented carbide substrate; andinterrmittently, during the deposition of the continuous oxide layer, pulsing into the first gaseous mixture to mix therewith at least one additional vapor selected from the halides of aluminum, zirconium, and yttrium, optionally mixed with a carrier gas; wherein the at least one additional vapor is different from the first halide vapor and is mixed at a partial pressure, at time intervals, and for lengths of time selected to form at least one discontinuous additional phase, dispersed as discrete particles within the continuous oxide layer, of at least one material selected from the group consisting of oxides of aluminum, zirconium, and yttrium to form a wear resistant composite ceramic layer on the cemented carbide substrate. - View Dependent Claims (4, 5, 6, 7, 8, 9, 10)
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11. A process for depositing a wear resistant composite coating on a cemented carbide substrate comprising the steps of:
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passing a halide vapor, optionally mixed with a carrier gas, over a mixture or alloy of two or more metals selected from the group consisting of aluminum, zirconium yttrium, and their metal salts, at about 250°
-250°
C., to form a first halide mixture comprising halides of two or more of aluminum, zirconium, and ytrrium, and optionally the carrier gas;mixing the first halide mixture with one or more volatile oxidizing gases to form a first gaseous mixture; and passing the first gaseous mixture over the cemented carbide substrate at a temperature of about 900°
-1250°
C. and a pressure between about 1 torr and about ambient pressure, to deposit a composite layer on the cemented carbide substrate;wherein the one or more volatile oxidizing gases, the flow rates of the gases, the surface areas and the ratio of the suface areas of the two or more metals, and the deposition time are selected so that the composite layer comprises an adherent layer about 0.1-20 microns thick of a continuous first phase of an oxide of one of the two or more of aluminum, zirconium, and yttrium, and at least one discontinuous additional phase, dispersed as discrete particles within the first-phase layer, of oxides of the remaining of the two or more of aluminum, zirconium, and yttrium. - View Dependent Claims (12, 13)
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14. A process for depositing a wear resistant composite coating on a cemented carbide substrate comprising the steps of:
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passing a first gaseous halide, optionally mixed with a first carriage gas, over a first metal selected from the group consisting of aluminum, zirconium, yttrium, and metal salts thereof, at 250°
-1250°
C., to form a gaseous first metal halide of aluminum, zirconium, or yttrium;passing a second gaseous halide, which may be the same or different from the first gaseous halide, optionally mixed with a second carrier gas, which may be the same or different from the first carrier gas, over one or more additional metals selected from the group consisting of aluminum, zirconium, yttrium, and alloys and metal salts thereof, and different from the first metal, at about 250°
-1250°
C., to form one or more additional metal halides of one or more of aluminum, zirconium, and ytrrium;passing a gaseous mixture comprising the first metal halides, the one or more additional metal halides, optionally the carrier gases, and one or more volatile oxidizing gases over the cemented carbide substrate, at a temperature of about 900°
-1250°
C. and at a pressure between about 1 torr and about ambient pressure to deposit a composite layer on the cemented carbide substrate;wherein the one or more volatile oxidizing gases, the flow rates of the vapors, the surface areas of the first metal and the one or more additional metals, and the deposition time are selected so that the composite layer comprises an adherent layer about 0.1-20 microns thick of a continuous first phase of an oxide of one of aluminum, zirconium, and yttrium, having at least one discontinuous additional phase of discrete particles of oxide(s) of one or more or aluminum, zirconium, and yttrium dispersed therein, the additional phase oxide(s) being different from the first-phase oxide. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22)
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Specification