Iron-nickel-cobalt magnetic powder and tape prepared therefrom

Claim 2

A ferromagnetic powder product comprising an alloy of: about 10 to 33 weight % iron about 8 to 30 weight % nickel about 50 to 82 weight % of cobalt said powder having a maximum average dimension of 5 microns, and which has: a coercivity of at least 500 a magnetic moment of at least 140 and a squareness of at least 0.5.

Claim 3

A product as defined in claim 1 but wherein said iron is from 10 to 24% and the nickel is at least 12%.

Claim 4

A product as defined in claim 1 which, when exposed to 50% relative humidity at 166° F. for 100 hours retains at least 50% of the specific magnetic moment which characterized it before said exposure.

Claim 5

A product as defined in claim 1 wherein said powder has a squareness of at least 0.72.

Claim 6

A product as defined in claim 2 which, when exposed to 50% relative humidity at 166° F. for 100 hours retains at least 50% of the specific magnetic moment which characterized it before said exposure.

Claim 7

A product as defined in claim 2 wherein said powder is formed of acicular particles having average length-to-width ratio of at least 3:1 and have length of from 0.3 to about 5 microns and has a squareness of at least 0.72.

Claim 8

A product as defined in claim 3 wherein said powder is formed of acicular particles having average length-to-width ratio of at least 3:1 and have length of from 0.3 to about 5 microns and has a squareness of at least 0.72.

Claim 9

A ferromagnetic powder product as defined in claim 1 wherein the alloy consists essentially of about 18 weight % iron about 18 weight % nickel about 64 weight % cobalt.

Claim 10

The ferro magnetic powder product defined in claim 5 wherein the alloy consists essentially of: about 18 weight % iron about 18 weight % manganese about 64 weight % cobalt.

Claim 11

The ferromagnetic powder product defined in claim 1 wherein the nickel is substituted for by manganese.

Claim 12

A magnetic recording medium of the type comprising a metallic powder dispersed in a polymeric binder wherein said powder is formed of an alloy consisting essentially of about 10 to 33 weight % iron, about 8 to 30 weight % nickel, and about 50 to 82 weight % cobalt; and wherein said powder is characterized by a. a minimum squareness of about 0.5 b. a minimum coercive force about 500 oersteds, a specific magnetic moment of 140 to 190, and a corrosion resistance characterized by the ability to maintain at least 50% of its specific magnetic moment when exposed to 50% relative humidity at 166° F. for 100 hours.

Claim 13

A magnetic recording medium of the type comprising a metallic powder dispersed in a polymeric binder wherein said powder is formed of an alloy consisting essentially of about 10 to 33 weight % iron, about 8 to 30 weight % nickel, and about 50 to 82 weight % cobalt; and wherein said powder is characterized by a. a minimum squareness of about 0.5 b. a minimum coercive force about 500 oersteds, a specific magnetic moment of 140 to 190, and a corrosion resistance characterized by the ability to maintain at least 50% of its specific magnetic moment when exposed to 50% relative humidity at 166° F. for 100 hours.

Claim 14

A recording medium as defined in claim 11 wherein the metallic powder has a squareness of at least 0.72.

Claim 15

A recording medium as defined in claim 12 wherein said iron is from 10 to 24% and the nickel is at least 12%.

Claim 16

A recording medium as defined in claim 13 wherein the metallic powder has a squareness of at least 0.72.

Claim 17

A recording medium as described in claim 11 wherein some of the nickel is replaced with manganese.

Claim 18

A recording medium as described in claim 11 wherein at least 70% of said specific magnetic moment is retained after said exposure.

Claim 19

A recording medium as described in claim 13 wherein at least 70% of said specific magnetic moment is retained after said exposure.

Claim 20

The recording medium defined in claim 11 wherein the alloy consists essentially of: about 18 weight % iron about 18 weight % nickel about 64 weight % cobalt.

Claim 21

The magnetic recording medium defined in claim 13 wherein the alloy consists essentially of: about 18 weight % iron about 18 weight % nickel about 64 weight % cobalt.

Claim 22

The medium defined in claim 14 wherein the alloy consists essentially of: about 18 weight % iron about 18 weight % nickel about 64 weight % cobalt.