GB987155A - Bearings - Google Patents

Abstract

A bearing surface is formed of material containing nickel oxide and/or cobalt oxide applied by projecting at least superficially molten particles of nickel oxide and/or cobalt oxide on to a substrate or by projecting at least superficially molten particles of nickel or cobalt on to a substrate and subsequently oxidizing them. In addition to the use of either or both of nickel and cobalt oxides, the bearing surface can be modified by including in addition nickel and/or cobalt metals (which may if desired be subsequently oxidized) or other additives and coadjutants. The substrate can be made of various materials such as stainless steel, mild steel, aluminium, ceramics and thermosetting plastics. The thickness of the bearing surface can be varied over a wide range, at least from 0.005 to 0.025 inch and suitably up to 0.085 inch. The following materials were charged into an 8-inch diameter rubber-lined ball mill:- .Green nickel oxide (200 B.S. mesh).2000 gm .Calcined alumina (200 B.S. mesh).160 gm . 1/2 -inch Alorite cylinders.2160 gm .Distilled water.1000 ml The mill was then rotated at 60 r.p.m. for six hours. After milling, the water was removed by drying at 105-110 DEG C. in an oven until the powder was almost dry. The damp powder was passed through a 22 B.S. sieve and pressed into a compact 1 1/2 inches x 1 inch x 1/2 inch at 2 tons per square inch. The compact was placed on coarse fused magnesia powder on an alumina tile and fired to 1500 DEG C. in an oxidizing atmosphere. After sintering, the compact was powdered by passing it through a jaw crusher and hammer mill. The powder was sieved into the following fractions:- .A..On 100 B.S.S .B..Through 100 B.S.S. on 200 B.S.S .C..Through 200 B.S.S. on 350 B.S.S .D..Through 350 B.S.S The (A) and (D) fractions were rejected and the (B) and (C) fractions were re-blended in the weight ratio of 1:4. The resultant powder was flame-sprayed on to a prepared stainless steel surface by the usual techniques and formed a bearing surface having a thickness of 0.02 inch. Alternatively the powder, after milling and drying, can be extruded into rod form after the addition of a suitable extrusion binder such as 20% by weight of a cellulose material in water. The extruded rods are dried for several hours, then fired to say 1450 DEG C. in air whilst supported on an inert material such as magnesia powder. These rods can then be used in a rod type of flame spraying gun to apply coatings as before.ALSO:A bearing surface is formed of material containing nickel oxide and/or cobalt oxide applied by projecting at least superficially molten particles of nickel oxide and/or cobalt oxide on to a substrate. In addition to the use of either or both of nickel and cobalt oxides, the bearing surface can be modified by including in addition nickel and/or cobalt metals (which may if desired be subsequently oxidized) or other additives and coadjutants. The substrate can be made of various materials such as stainless steel, mild steel, aluminium, ceramics and thermosetting plastics. The thickness of the bearing surface can be varied over a wide range, at least from 0,005-0,025 inch and suitably up to 0,085 inch. The powder may be flame-sprayed on to a prepared stainless steel surface by the usual techniques and form a bearing surface having a thickness of 0,02 inch. Alternatively the powder, after milling and drying, can be extruded into rod form after the addition of a suitable extrusion binder such as 20% by weight of a cellulose material in water. The extruded rods are dried for several hours, then fired to say 1450 DEG C. in air whilst supported on an inert material such as magnesia powder. These rods can then be used in a rod type of flame spraying gun to apply coatings as before.