JPS6293359A - Ceramic coating - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates generally to ceramic material coatings on substrates, and more particularly to coatings on the surface of article supports to provide a thermal barrier layer to an article. The present invention can be used to coat parts of combustion engines, such as piston crowns, cylinder walls, cylinder heads, valve heads, and exhaust ports, to reduce combustion heat loss to achieve adiabatic operation of the engine. . The present invention will be described below.
Although conveniently described in connection with this application, it should be recognized that the present invention can be used for other coatings.

Recent advances in increasing the useful power available from combustion engines and improving their efficiency include manufacturing various engine components that are at least partially made of ceramic materials. These materials have low thermal conductivity, high strength, high fracture toughness, high thermal shock resistance, good wear resistance, thermal expansion matching that of the steel or iron commonly used with this material, and high erosion resistance. Used because of desirable properties such as sex. One particularly used ceramic material of this type is partially stabilized zirconia (P
(known as SZ).

Ceramic materials can be molded into integral engine parts such as cylinder linings and piston crowns, and can also be coated onto these parts.

Although it has been recognized that the use of ceramic materials improves engine operation, monolithic ceramic materials are fairly heavy and therefore only small amounts can be used without adversely affecting engine operation. Additionally, this material is fairly expensive, which can increase the cost of engine parts. In any case, in order to further improve engine operation, it would be desirable to further reduce combustion heat losses.

It is an object of the present invention to provide a ceramic material coating for a support (for example a combustion engine component), which makes it possible to alleviate the above-mentioned disadvantages of conventional solutions using ceramic materials.

With this in mind, the present invention, in one aspect, includes a plurality of laminated coating layers, at least some of which have a composition containing a proportionate amount of a ceramic material; The present invention provides a coating for a substrate in which the proportional amount relationship of materials differs between coating layers.

In another aspect, the invention includes laminating a plurality of coating layers to a support, at least some of the layers having a composition containing a ceramic material in a proportional amount relationship. , provides a method of coating a substrate in which the proportional dosing relationship of the ceramic material is different between the coating layers.

Preferably, the coating layers are arranged in a largely or at least substantially mutually graded manner, depending on the amount of ceramic material contained in the layer composition. In this regard, each layer is preferably arranged such that the proportionate proportion of the ceramic material increases continuously from the support.

At least one of the coating layers preferably has a thickness of 50
Contains ceramic material below the capacity factor.

The coating layer adjacent to the support preferably contains 0% or nearly 0 volume of ceramic material. This coating layer preferably acts as a bonding layer or transition layer between the support and the other layers.

At least one of the coating layers preferably has a thickness of about 5
Contains a ceramic material with a capacity factor of 0 or more. The outermost coating layer from the support is preferably 100%
or approximately 100 g (volume) of ceramic material.

Each coating layer preferably has a composition density that varies from layer to layer according to the proportional amount relationship of their ceramic materials. In this regard, preferably the layer density increases with increasing amount of ceramic material, so that the coating preferably has a density gradient that increases outwardly from the support.

Preferably, the same ceramic material is used for each coating layer in which it is present. Coating layer compositions containing less than 100 parts of ceramic material preferably contain a residual amount of filler of 100 parts. This filler preferably has an affinity for ceramic materials, preferably metallic materials.

Each coating layer preferably has approximately the same thickness.

Furthermore, these layers preferably have a constant thickness throughout them.

Preferably each coating layer is applied by spraying onto the support or onto the preceding layer. Each layer composition is preferably prepared in powder form and then heated and melted before spraying. Preferably, the coating is applied using a suitable heated spraying device.

In one preferred form of the invention, the coating comprises at least 6 coating layers.

In this configuration, the layer adjacent to the support contains approximately 0% ceramic material, the outermost layer contains approximately 100% ceramic material, while the intermediate coating layer (or layers) contains approximately 0% ceramic material. 100% (by volume) of ceramic material. In this configuration, six intermediate layers can be applied, each successive layer containing approximately 25%, 50 and 75 parts of ceramic material.

In one preferred form, the ceramic material is a zirconia-based material. This ceramic material may be a fully or partially stabilized zirconia material. The ceramic material may also be an yttria-zirconia material.

In one preferred form, the coating layer containing less than 100 parts of the ceramic material contains a balance of filler that is any suitable metal or alloy thereof. In this connection, this material may be nickel-chromium, although depending on the composition of the support and the nature of the ceramic material, nickel or chromium or other metals or alloys thereof are likewise suitable. The support generally consists of metal, such as steel or iron and alloys thereof. In one preferred form, each coating layer is about 0.005 inches (about 0.127 mm) thick.

In one preferred form of the invention, each coating layer is sprayed by a heated spraying device using a plasma flame as the heat source for melting the layer composition.

Devices of this type have a structure well known to those skilled in the art and can be used in a well known manner.

In one preferred embodiment, the surface of the support on which each layer is applied can be appropriately prepared before the coating layer is applied. In this regard, the support surface can be cleaned and roughened, for example by grid blasting. After coating the support, the outermost surface of the coating can be optionally treated (eg, smoothed by grinding, etc.).

According to the coating of the present invention, in the article to which the coating is applied, compared to conventional approaches for providing articles of this type, at least in part made of ceramic material:
The amount of ceramic material used can be reduced, resulting in a reduction in overall weight. This is accomplished without impairing the performance of the articles to which this coating may be applied (eg, combustion engine components). In fact, the thermal conductivity of this coating is believed to be lower than that of monolithic ceramic materials.

The process of applying the coating according to the invention can be carried out using existing equipment and, in this respect, does not require large additional investments. This minimizes the cost of providing articles with the coating of the invention, and thus the cost of these articles themselves.

It should be recognized that the coating and its application may be modified and/or varied without departing from the scope of the invention as defined in the claims.

(J2)

Claims (16)

[Claims] (1) A support consisting of several layers of laminated coating layers with compositions containing different amounts of ceramic material in each layer, the amounts of ceramic contained in the layers being proportional to each other. Body coating. 2. The coating of claim 1, wherein the coating layers are at least substantially mutually graded according to the amount of ceramic material in each layer. (3) A coating according to claim 2, wherein each coating layer is arranged such that the proportional quantity relationship of the ceramic material contained in the coating layer increases continuously from the support. (4) The coating according to any one of claims 1 to 3, wherein at least one of the coating layers contains 50% by volume or less of a ceramic material. (5) A coating according to any one of claims 1 to 4, wherein the coating layer adjacent to the support contains 0% or nearly 0% (by volume) of ceramic material. (6) The coating according to any one of claims 1 to 5, wherein at least one of the coating layers contains about 50% or more by volume of ceramic material. 7. A coating according to any one of claims 1 to 6, wherein the outermost coating layer from the support contains 100% or nearly 100% by volume of ceramic material. (8) five coating layers are applied, each successive layer from the support being at least about 0%, 25%, 50%, 75%;
and about 100% (by volume) of ceramic material. (9) Each coating layer is approximately 0.005 inches (approximately 0.1
9. A coating according to any one of claims 1 to 8, having a thickness of 27 mm). (10) The coating according to any one of claims 1 to 9, wherein the ceramic material is a zirconia-based material. (11) laminating a plurality of coating layers to a support, at least some of the layers having a composition containing a proportionate amount of a ceramic material; A method of coating a support in which the quantity relationship differs between the coating layers. 12. The method of claim 11, wherein each coating layer is applied sequentially by spraying onto the support or onto a preceding coating layer. (13) The method according to claim 12, wherein each coating layer composition is first prepared in powder form, heated and melted, and then applied to the support by spraying. 14. The method of claim 13, wherein each coating layer composition is melted by a plasma flame heat source. (15) The surface of the support to which the coating layer is applied is cleaned and roughened before application of the coating layer, thereby assisting in retention of the coating on the support. The method described in any of the paragraphs. (16) The method according to any one of claims 11 to 15, wherein the applied coating is as described in any one of claims 1 to 10.