Corrosion resistant cermet wear parts
AssigneeKennametal Inc.
InventorsWilliam M. Stoll, James P. Materkowski, Ted R. Massa
Life of this patent
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Abstract
A corrosion resistant cermet comprises a ceramic component (e.g., WC) and a binder alloy comprised of a major component (e.g., one or more of iron, nickel, cobalt, their mixtures, and their alloys) and at least one additive component (e.g., one or more of ruthenium, rhodium, palladium, osmium, iridium, and platinum). Plungers for hyper compressors used in the corrosive environments generated during the manufacture of low density polyethylene (LDPE) or ethylene copolymers are an example of the use of the corrosion resistant cermet.
Claims34
A corrosion and wear resistant cermet composition comprising:
- (a) at least one ceramic component comprised of at least one of boride(s), carbide(s), nitride(s), oxide(s), silicide(s), their mixtures, their solutions, and combinations thereof;
- and
- (b) between about 6-19% by weight binder alloy comprised of a major component comprising one or more of iron, nickel, cobalt, their mixtures, and their alloys and an additive component comprising between about 26-65% by weight of the binder alloy and at least one of ruthenium, rhodium, palladium, osmium, iridium, platinum, their alloy, and mixtures thereof,
- wherein the additive component imparts corrosion resistance against at least one of acids, bases, salts, lubricants, gasses, silicates, or any combination of the preceding to the corrosion and wear resistant cermet composition.
A corrosion and wear resistant cermet composition comprising:
- (a) tungsten carbide and
- (b) between about 6-19% by weight binder alloy comprising cobalt and between about 26-65% by weight ruthenium,
- wherein the combination of the cobalt and ruthenium imparts improved corrosion resistance in acid/water solutions comprised of at least one of formic acid, acetic acid, methacrylic acid, and maleic acid
- wherein the corrosion and wear resistant cermet composition has:
- a Rockwell A hardness of at least about 85;
- a transverse rupture strength of at least about 1.7 GPa (250 ksi);
- and
- a corrosion rate after about seven (7) days at about 50.degree. C. (122.degree. F.) in a one (1)% acid/water solutions comprised of at least one of formic acid, acetic acid, methacrylic acid, and maleic acid of not greater than about 120 m.d.d.
A corrosion and wear resistant cermet composition comprising:
- (a) tungsten carbide and
- (b) between about 6-19% by weight binder alloy comprising cobalt and between about 26-65% by weight ruthenium,
- wherein the combination of the cobalt and ruthenium imparts improved corrosion resistance in acid/water solutions comprised of at least one of sulfuric acid, nitric acid, and hydrochloric acid;
- sea water;
- or hydrazine mono-hydrate/water solutions
- wherein the corrosion and wear resistant cermet composition has:
- a Rockwell A hardness of at least about 85;
- a transverse rupture strength of at least about 1.7 GPa (250 ksi);
- and
- a corrosion rate after about seven (7) days at about 65.degree. C. (149.degree. F.) in:
- a five (5)% acid/water solution comprised of at least one of sulfuric acid and nitric acid;
- a 37% hydrochloric acid/water solution;
- synthetic sea water;
- or
- 98% hydrazine mono-hydrate/water solution of not greater than about 80 m.d.d.
Dependencies are inferred from the claim text.