Encapsulated Wear Particles

Abstract

Incorporating hard particles in a matrix forming the surface of a member can significantly increase wear resistance. Practical use of diamond in industrial applications is limited as the carbon structure breaks down to graphite in air at temperatures over 700° C. When exposed to molten iron the diamond surface can also chemically react and dissolve into the iron. Metal compounds that coat the diamond can provide one or more protective layers that limit contact of the diamond surface with elements that will degrade its structure. Coating can also provide a wettable surface for the molten matrix during processing to improve retention of the particle in the matrix.

Description

FIELD OF THE INVENTION[0001]This invention relates to component wear surfaces with embedded wear particles to increase hardness and limit erosion of the surface.BACKGROUND OF THE INVENTION[0002]Industrial applications often put tools in cyclic contact with abrasive materials that remove the surface of the tool. Over the service life of the tool the abrasive materials wear away and erode the exposed tool surface until the tool has to be replaced. A harder surface for the tool can extend the service life of the tool by reducing the rate of wear during operation.[0003]Wear tools can be manufactured by casting, powder metallurgy infiltration or other techniques. Methods for modifying the hardness of tool materials include alloying, case hardening and heat treating. Incorporating wear resistant particles or materials into the body of the tool during forming of the part can also limit erosion during operation to provide increased service life.[0004]Material preparations and manufacturing ...

AI Technical Summary

Benefits of technology

This patent is about using hard particles coated with a metal nitride layer or metal carbide and metal nitride layers to improve the abrasion and erosion resistance of tools and parts exposed to molten metal. The hard particles can be embedded in the metal matrix or added to the surface through manufacturing processes. The metal nitride layer acts as a protective barrier for the metal carbide layer, limiting degradation. In some embodiments, a sub-stoichiometric metal nitride layer is used to better interact with the molten matrix. This improves the retention of the hard particles and increases the useful life of products exposed to abrasive wear. Additionally, a wear-resistant surface can be deposited on metal substrates using arc welding with a metal matrix containing hard particles. The particles pass from the binder on the welding rod to the welding pool and are incorporated into the surface on solidification, providing further resistance to abrasion and erosion.

Problems solved by technology

Surfaces of wear tools and wear members that are in sliding or impacting contact with other materials are subject to erosion.

Ground engaging tools have very high rates of wear and must be replaced frequently.

Practical use of diamond in industrial applications is limited as the diamond structure can break down to graphite in air at temperatures over 700° C. When exposed to molten iron the diamond surface can also chemically react and dissolve into the iron.

Common practice has taught away from embedding multi-coated diamond in ferrous castings as coatings would not be able to protect the diamond from high casting temperatures and aggressive chemical attack.

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