AU2008100064A4 - Improved ceramic/polymer composite resistant material - Google Patents

Description

22/01 2008 TUE 16:46 FAX Smoorenburg Attorneys IP AUSTRALIA [004/017 00 1 IMPROVED CERAMICIPOLYMER COMPOSITE WEAR RESISTANT ctMATERIAL C-i RELATED APPLICATIONS This application claims priority to Australian Provisional Patent Application No. 2006906038 in the name of Maintain Epoxy Resins Pty Ltd, which was filed Son 1 November 2006, entitled "Improved Ceramic Polymer Wear Resistant Material" and the specification thereof is incorporated herein by reference in its entirety and for all purposes.

00 oO FIELD OF INVENTION This invention relates to the field of wear resistant materials. In one form, the invention relates to ceramic polymer composites and it will be convenient to hereinafter describe the invention in relation to the use of ceramic polymer composites in the area of materials handling, however it should be appreciated that the invention is not limited to that use, only.

BACKGROUND

The discussion that follows is intended to aid in the understanding of the present invention. It is not intended that this discussion is an admission that content of the discussion is considered common general knowledge In the field of wear resistant materials there are a number of approaches that have been applied to increase the service life of the components subject to extensive wear. The approaches generally fall into three categories 1. Apply more material, 2. Use harder materials, more wear resistant materials 3. Use composite materials that have hard wear resistant component, and softer tougher materials to hold the wear materials together.

Techniques one and two have been applied in the field of metallic based materials. One of the problems with the use of metallic materials is the weight of the components. With an increasing focus placed on safety it is desirable to reduce the weigh of the components as much as possible. Clearly the application of more material does not address the safety issue.

As the wear resistant materials have increased in hardness, they have also increased in brittleness. As the hardness increases it is often required to provide some support to the wear material to prevent the wear resistant portion from COMS ID No: ARCS-176283 Received by IP Australia: Time 16:51 Date 2008-01-22 22/01 2008 TUE 16:46 FAX Smoorenburg Attorneys IP AUSTRALIA [005/017 00 2 fracturing and thus leaving the underlying structure venerable to accelerated Swear.

SThe harder wear resistant materials used are often so hard that they are easily fractured by material impinging on the surface resulting in premature wear.

The use of a polymer ceramic composite has been found to produce Sreasonable wear characteristics because it allows the use of an extremely hard ceramic with excellent wear properties that is cushioned by the polymer backing.

One of the major problems with this approach is the ceramic component oO 0either breaks up with the impact of the impinging material or alternatively the ceramic component separates from the polymer substrate.

SUMMARY OF INVENTION It is an object of the present invention to alleviate at least one disadvantage associated with the prior art or to at least provide a useful alternative to prior art systems.

In one aspect of embodiments described herein there is provided a ceramic wear tile adapted for use in a wear plate, the tile including a channel extending substantially across one entire face of the tile wherein the channel is adapted to form a key means for mechanical attachment to a polymer substrate of a wear plate.

Preferably, the channel is configured such that at least one dimension of the channel decreases towards the edge of the tile.

In another aspect of embodiments described herein there is provided a composite wear plate including: a polymer backing and; a plurality of the wear tiles as disclosed herein wherein the wear tiles are disposed in a randomly oriented array having their faces including the channel bonded to the polymer backing.

In yet another aspect of embodiments described herein there is provided a method of assembling a composite wear plate, the method including the steps of: forming an array of ceramic wear tiles, each tile having a channel face including a channel extending substantially across one entire face of the tile and an opposing face forming a wear face, wherein the tiles in the array are arranged such that the wear faces are disposed in the same direction and the channels of COMS ID No: ARCS-176283 Received by IP Australia: Time 16:51 Date 2008-01-22 22/01 2008 TUE 16:47 FAX Smoorenburg Attorneys IP AUSTRALIA R006/017 00 3 the opposing faces are randomly oriented to prevent channels running in one c direction; applying a polymer material to the channel faces of the tile array such that N the polymer substantially fills the channels and forms a polymer backing plate; applying an attachment plate to the polymer material before the polymer Smaterial cures.

In one further aspect of embodiments described herein there is provided an improved ceramic polymer composite wear material in the form of a wear plate oO 0including ceramic wear tiles bonded to a polymer backing wherein the ceramic wear tile incorporates a channel extending across the face of the tile in contact with the polymer backing and opposed to the wear face.

In a preferred embodiment the channel in the ceramic wear tile is narrower at the surface of the tile than in the body of the tile. This provides the advantage of acting as a key. With the polymer worked into the channel the ceramic wear tile is mechanically attached to the wear plate as a whole. This mechanical attachment provides superior impact resistance and resistance to spalling of the ceramic wear tile in use.

Preferably, at least one of the edges of the channel has a radius of curvature. The edges with a radius may include either of the edges defining the top channel or the edges defining the bottom of the channel. Preferably all four edges have radii. The radius of edges on the top of the channel prevents cutting of the polymer when is use. The radius of edges at the bottom of the channel act to minimize stress concentrations within the ceramic and thus minimise the chances of the ceramic failing due to impact loads.

In a preferred embodiment fasteners are provided to attach the wear plate to the object being protected from wear. It has been found that the most efficient way for attaching the wear plate in the field has been to provide threaded studs.

Provision of threaded studs is accomplished by welding a stud to a backing plate and casting the backing plate in to the polymer after the polymer has been worked into the channels in the back of the wear resistant tiles and before the polymer has cured.

Preferably, the composite wear plate is manufactured using ceramic tiles that are substantially cubic. It has been found that substantially cubic tiles have COMS ID No: ARCS-176283 Received by IP Australia: Time 16:51 Date 2008-01-22 22/01 2008 TUE 16:47 FAX Smoorenburg Attorneys IP AUSTRALIA 1007/017 00 4 the advantage of being less prone to failure than generally rectangular tiles. In Sservice they are less likely to fail and spall parts of the ceramic exposing the C-i polymer backing to excessive wear.

Preferably, the ceramic tiles are manufactured from at least one of the following about 89% alumina, about 95% alumina, and Silicon carbide. These O materials are particularly advantageous in high wear applications.

With the above in mind, further aspects of embodiments of the invention provide for a method of materials handling including the use of the composite 00 oO wear plate as disclosed herein.

Other aspects and preferred forms are disclosed in the specification and/or defined in the appended claims, forming a part of the description of the invention.

Further scope of applicability of embodiments of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the disclosure herein will become apparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS Further disclosure, objects, advantages and aspects of preferred and other embodiments of the present application may be better understood by those skilled in the relevant art by reference to the following description of embodiments taken in conjunction with the accompanying drawings, which are given by way of illustration only, and thus are not limitative of the disclosure herein, and in which: Figure 1 is an isometric view of a ceramic wear tile in accordance with one embodiment; Figure 2 consists of two respective side views of the ceramic wear tile of figure 1; Figure 3 is a plan view showing an array of ceramic wear tiles forming a wear plate in accordance with another embodiment; Figure 4 is a side view of a completed wear plate in accordance with an embodiment including tiles as shown in figure 1 and showing a wear block polymer backing and attachment studs.

COMS ID No: ARCS-176283 Received by IP Australia: Time 16:51 Date 2008-01-22 22/01 2008 TUE 16:48 FAX Smoorenburg Attorneys IP AUSTRALIA R008/017 00 DETAILED DESCRIPTION It will now be convenient to describe the present invention by way of c example and with reference to the accompanying figures.

in order to overcome the problems with the prior art it was considered necessary to devise a way of more securely attaching a ceramic wear tile O (Figure 1) to a polymer backing 60 (Figure 4) to form a wear plate 70 shown in Figure 4.

The ceramic tile shown in Figure 1 is manufactured of a ceramic suitable 00 oO 0for a wear application. Ceramic wear tiles 10 suitable for use in a high wear application are those ceramics that have good abrasion resistance. Suitable ceramics include but are not limited to oxide and carbide ceramics. Examples of a useful ceramics are alumina and silicon carbide. Particularly useful ceramics are composed of about 89 to about 95% alumina.

The ceramic wear tiles 10 used in this application are nominally substantially cube shaped with sizes ranging from about 15mm to about 50 mm.

The size of the tiles being used has to be balanced with the mechanical properties of the material and the application of the final wear plate 70. If the ceramic wear tiles 10 are too big and the application has significant impact loading it is possible that the ceramic wear tiles 10 will break up and the portion of the ceramic wear tile 10 will separate from the wear plate. If the ceramic wear tile is too small and the wear is aggressive the ceramic wear tile 10 will wear prematurely due to the joins between the ceramic wear tiles 10 being gouged out and further because of the relative thinness of the ceramic wear tiles 10, there is a minimal amount of the material available to be sacrificially worn.

In order to provide a more effecting bonding arrangement between the ceramic wear tile 10 and the polymer backing 60 (Figure 4) the ceramic wear tile has been modified to allow for a mechanical bonding and to provide greater surface area to increase surface adhesion.

The ceramic wear tile 10 has been modified by incorporating a channel in to the back face 20. The back face 20 incorporating the channel 30 is not the face of the ceramic wear tile 10 usually subject to wear. The channel 30 extends substantially across the entire back face 20 of the wear tile 10 from a first edge to the opposing edge 26. In a preferred embodiment the depth of the channel COMS ID No: ARCS-176283 Received by IP Australia: Time 16:51 Date 2008-01-22 22/01 2008 TUE 16:48 FAX Smoorenburg Attorneys IP AUSTRALIA Q009/017 00 6 is between about 15 and about 50 percent of the thickness of the ceramic wear Stile SThe channel 30 has substantially parallel sides 35; although in an alternative embodiment the sides 35 may not be parallel and may form a wedge shape with the narrow portion of the wedge located at or proximate the back face INO 20 and the wider portion of the wedge being in the body of the wear tile 10. This wedge shape provides the advantage of acting as a key to mechanically fasten the ceramic wear tile 10 to the polymer backing 60 when the polymer is worked 00 oO into the channel In a preferred embodiment the edges 38 defining the channel 30 and the back face 20 of the tile have a radius of curvature 36 shown in figure 2. The edge radius 36 is present so that when in use sharp edges do not cut into the polymer backing 60 leading to premature failure of the wear plate.

Also in a preferred embodiment the bottom of the channel 30 has at least one radius of curvature 39. Depending on the size of the ceramic wear tile and the width of the channel 30 the bottom 40 of the channel 30 becomes semi circular or even bulbous. If the ceramic wear tile 10 is quite large the channel forms flat bottom channel 30 with radii 39 along the transition from the sides 35 to the bottom The reason for the radii 39 in the bottom of the channel 30 is to minimize stress concentrations in the centre of the ceramic wear tile 10. If the channel was constructed will parallel sides and sharp corners the impact of material on the wear face 15 would result in the stress being transferred through the tile 10 and would be concentrated into the internal edges 39 this may result in premature failure of the wear tile The ceramic wear tile 10 has been specifically manufactured in a substantially cubic configuration so that the tile can be placed in an orientation such that the channel 30 can be orientated so as to not always run in the same direction. This change in orientation of the channel 30 provides additional stability for the final wear plate 70. In the third dimension (thickness) a cube size has been found to be beneficial as it allows for the channel 30 in the back 20 of the ceramic wear tile 10 but at the same time allows for sufficient material to be present to achieve satisfactory in service wear results.

COMS ID No: ARCS-176283 Received by IP Australia: Time 16:51 Date 2008-01-22 22/01 2008 TUE 16:49 FAX Smoorenburg Attorneys IP AUSTRALIA Q010/017 00 7 The ceramic wear tiles 10 are arranged in an array 50 shown in Figures 3 Sand 4 and are then bonded to a polymer backing 60 that holds the ceramic wear tiles 10 together. The polymer backing 60 may also be used to bond steel plates having threaded studs 56 to the back of the wear plate 70. The studs 56 are used to mechanically fasten the wear plate 70 in the field to whatever it is being IDused to protect.

Suitable polymers for use as the backing include but are not limited to natural, synthetic rubber, and polyurethane. The polymer needs to be able to be 00 able to be cast for reasons that will become apparent later Preferably the polymer will be specifically selected to have optimised properties for the end use of the wear plate 70. The polymer needs to be hard enough to support the weigh of the completed wear plate 70 and the forces imposed on the wear plate 70 when being attached to the application. However it is also desirable for the polymer to have sufficient yield to provide some "cushioning" to the ceramic wear tile 10. In service this cushioning assists in minimising the fracture of the ceramic wear tiles 10 by helping absorb impact loadings. A typical hardness of the fully cured polymer may be in the range of about 50 to about 95 shore A.

The Assembly Procedure The ceramic wear tiles 10 are coated in a boding agent such as that sold under the trademark "Chemlok 213". In a preferred embodiment the bonding agent is a propriety-bonding agent. The ceramic wear tiles 10 are arranged wear face 15 down in a mould in a staggered patter similar to that used to lay house bricks as shown In Figure 3. The channel 30 in the back 20 of the ceramic wear tile 10 randomly orientated so that the channels 30 do no all run in one direction.

Once the ceramic wear tiles 30 are laid out to form an array 50 in the mould a polymer is poured over the back surface 20 of the ceramic wear tiles The polymer is worked into the channels 30 such that the substantially all air is worked out of the channels 30. In an application where plates 55 with threaded studs 56 are to be employed, to fasten the wear plate 70, the plate 55 with a stud 56 pre welded to it is placed into the polymer after the polymer has been worked into the channels 30 and before the polymer cures.

COMS ID No: ARCS-176283 Received by IP Australia: Time 16:51 Date 2008-01-22 22/01 2008 TUE 16:49 FAX Smoorenburg Attorneys IP AUSTRALIA R011/017 00 8 It is important that the polymer be worked into the channels 30 to ensure ct an adequate bond across substantially all of the available surface area. The N modified ceramic wear tile 10 has a number of benefits in the bonding of the N ceramic wear tile 10 to the polymer backing The modification of providing a channel 30 increases the surface area Sbetween the ceramic wear tile 10 and the polymer backing 60 providing greater bonding area. Further, channel 30 also provides a mechanical attachment means.

_In the event of the adhesive bond degrading there is mechanical interlock present oO 0between the ceramic wear tile 10 and the polymer backing 60 that assists in keeping the ceramic wear tile 10 attached to the polymer backing While this invention has been described in connection with specific embodiments thereof, it will be understood that it is capable of further modification(s). This application is intended to cover any variations uses or adaptations of the invention following in general, the principles of the invention and including such departures from the present disclosure as come within known or customary practice within the art to which the invention pertains and as may be applied to the essential features hereinbefore set forth.

As the present invention may be embodied in several forms without departing from the spirit of the essential characteristics of the invention, it should be understood that the above described embodiments are not to limit the present invention unless otherwise specified, but rather should be construed broadly within the spirit and scope of the invention as defined in the appended claims.

The described embodiments are to be considered in all respects as illustrative only and not restrictive.

Various modifications and equivalent arrangements are intended to be included within the spirit and scope of the invention and appended claims.

Therefore, the specific embodiments are to be understood to be illustrative of the many ways in which the principles of the present invention may be practiced. In the following claims, means-plus-function clauses are intended to cover structures as performing the defined function and not only structural equivalents, but also equivalent structures. For example, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface to secure COMS ID No: ARCS-176283 Received by IP Australia: Time 16:51 Date 2008-01-22 22/01 2008 TUE 16:50 FAX Smoorenburg Attorneys IP AUSTRALIA R012/017 00 0 9 N wooden parts together, in the environment of fastening wooden parts, a nail and a Sscrew are equivalent structures.

S"Includes/including" when used in this specification is taken to specify the N presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, Scomponents or groups thereof." Thus, unless the context clearly requires otherwise, throughout the description and the claims, the words 'include', _'including', and the like are to be construed in an inclusive sense as opposed to 0 an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to".

COMS ID No: ARCS-176283 Received by IP Australia: Time 16:51 Date 2008-01-22

Claims (2)

1. 3. The composite wear plate of any one of the preceding claims wherein at least one backing plate with a stud is cast into the polymer.
2. 4. The composite wear plate of any one of the preceding claims wherein the ceramic tiles are manufactured from at least one of the following, about 89% alumina, about 95% alumina and Silicon carbide. A ceramic wear tile adapted for use in a wear plate, the tile including a channel extending substantially across one entire face of the tile wherein the channel is adapted to form a key means for mechanical attachment to a polymer substrate of a wear plate. COMS ID No: ARCS-176283 Received by IP Australia: Time 16:51 Date 2008-01-22