Magnetic head with tape-contacting guard surface and pole tips of similar iron-based materials

Claim 2

A magnetic head comprising head-tips, and a guard member having a similar composition to the head-tips and being substantially nonmagnetic under working conditions, the head-tips and the guard member being formed of magnetic and substantially nonmagnetic iron-silicon-aluminum alloys respectively, the headtips having a composition by weight of about 5 percent to about 8 percent aluminum, about 8 percent to about 11 percent silicon and about 81 percent to about 86 percent iron, and the guard member being of a composition by weight comprising about 18 percent to about 50 percent aluminum, and remainder comprising at least about 50 percent iron.

Claim 3

A magnetic head as claimed in claim 1 wherein the guard member is made of an alloy having a Curie point lower than that of the magnetic alloy of the head-tips, said Curie point of said guard member being lower than room temperature, the guard member being of a composition by weight of approximately 30 percent aluminum, 3 percent silicon and 67 percent iron.

Claim 4

A magnetic head comprising head-tips of a ferrite material, made of about 50 mol percent iron oxide, 40 mol percent manganese oxide, and 10 mol percent zinc oxide, and a guard member made of an iron-aluminum alloy having a Curie point lower than that of the ferrite material, said Curie point of said guard member being lower than room temperature, said guard member having a composition by weight comprising about 40 percent aluminum and 60 percent iron, both the head-tips and the guard member being disposed for contact with a magnetic tape record medium.

Claim 5

A magnetic head comprising head-tips of a ferrite material, made of about 50 mol percent iron oxide, 40 mol percent manganese oxide, and 10 mol percent zinc oxide, and a guard member made of an iron-aluminum alloy having a Curie point lower than that of the ferrite material, said Curie point of said guard member being lower than room temperature, said guard member having a composition by weight comprising about 40 percent aluminum and 60 percent iron, both the head-tips and the guard member being disposed for contact with a magnetic tape record medium.

Claim 6

A magnetic head comprising head-tips, and a guard member having a similar composition to the head-tips and being substantially nonmagnetic under working conditions, the head-tips being of an alloy material in as cast condition and having a composition by weight of 5 percent to 8 percent aluminum, 8 percent to 11 percent silicon and 81 percent to 86 percent iron, and the guard member for the head-tips being of a composition by weight comprising 18 percent to 50 percent aluminum, and the remainder comprising at least 50 percent iron.

Claim 7

A magnetic head comprising head-tips, and a guard member having a similar composition to the head-tips and being substantially nonmagnetic under working conditions, the head-tips being of an alloy material in as cast condition and having a composition by weight of 5 percent to 8 percent aluminum, 8 percent to 11 percent silicon and 81 percent to 86 percent iron, and the guard member for the head-tips being of a composition by weight comprising 18 percent to 50 percent aluminum, and the remainder comprising at least 50 percent iron.

Claim 8

A magnetic head as claimed in claim 4 wherein the head-tips have a composition by weight of approximately 5 percent to 6 percent aluminum, 9 percent to 10 percent silicon and about 85 percent iron, and the guard member has a composition by weight of approximately 30 percent aluminum, 3 percent silicon and 67 percent iron.

Claim 9

A magnetic head comprising head-tips of a ferrite material, and A guard member adjacent the head-tips having a composition by weight comprising 18 percent to 50 percent aluminum, and the remainder comprising at least 50 percent iron, and providing a leakage reluctance greater than the reluctance of the coupling gap of the head-tips.

Claim 10

A magnetic head comprising head-tips of a ferrite material, and A guard member adjacent the head-tips having a composition by weight comprising 18 percent to 50 percent aluminum, and the remainder comprising at least 50 percent iron, and providing a leakage reluctance greater than the reluctance of the coupling gap of the head-tips.

Claim 11

A magnetic head comprising head-tips having a tape contact surface formed of a magnetic iron-silicon-aluminum alloy having a composition by weight of about 5 percent to about 8 percent aluminum, about 8 percent to about 11 percent silicon and about 81 percent to about 86 percent iron, and a guard member provided near the head-tips and having a tape contact surface substantially flush with the tape contact surface of the head-tips, at least the contact surface of the guard member being formed of a material of similar composition to that of the tape contact surface of the head-tips having a composition by weight comprising about 18 percent to about 50 percent aluminum, and the remainder comprising at least about 50 percent iron, said material of the guard member contact surface having a Vickers hardness which exceeds 300 at room temperature and which exceeds 250 at 200* C. and having a Curie point lower than that of the magnetic alloy of the head-tips, said Curie point of said material of said guard member contact surface being lower than room temperature.

Claim 12

A magnetic head comprising head-tips having a tape contact surface formed of a magnetic iron-silicon-aluminum alloy having a composition by weight of about 5 percent to about 8 percent aluminum, about 8 percent to about 11 percent silicon and about 81 percent to about 86 percent iron, and a guard member provided near the head-tips and having a tape contact surface substantially flush with the tape contact surface of the head-tips, at least the contact surface of the guard member being formed of a material of similar composition to that of the tape contact surface of the head-tips having a composition by weight comprising about 18 percent to about 50 percent aluminum, and the remainder comprising at least about 50 percent iron, said material of the guard member contact surface having a Vickers hardness which exceeds 300 at room temperature and which exceeds 250 at 200* C. and having a Curie point lower than that of the magnetic alloy of the head-tips, said Curie point of said material of said guard member contact surface being lower than room temperature.

Claim 13

A magnetic head in accordance with claim 7 with said guard member tape contact surface being formed of substantially nonmagnetic alloy and having a composition by weight of approximately 30 percent aluminum, 3 percent silicon and 67 percent iron.

Claim 14

A magnetic head in accordance with claim 8 with said head-tips having a composition by weight of approximately 5 percent to 6 percent aluminum, 9 percent to 10 percent silicon and about 85 percent iron, and the guard member having a composition by weight of approximately 30 percent aluminum, 3 percent silicon and 67 percent iron.

Claim 15

A magnetic head comprising head-tips having a tape contact surface formed of a magnetic iron base alloy material including substantial amounts of iron and aluminum, and a guard member provided near the head-tips and having a tape contact surface substantially flush with the tape contact surface of the head-tips, at least the contact surface of the guard member being formed of an iron base alloy material having substantial amounts of iron and aluminum, said material of the guard member contact surface having a Vickers hardness which exceeds 300 at room temperature and which exceeds 250 at 200* C. and having a Curie point lower than that of the magnetic alloy material of the head-tips, the alloy material of said guard member contact surface containing about 18 percent to 50 percent by weight of aluminum and having a Curie point lower than room temperature, and the material of the guard member contact surface having similar temperature-hardness characteristics to that of the head-tips under working temperature conditions of the magnetic head.

Claim 16

A magnetic head comprising head-tips having a tape contact surface formed of a magnetic iron base alloy material including substantial amounts of iron and aluminum, and a guard member provided near the head-tips and having a tape contact surface substantially flush with the tape contact surface of the head-tips, at least the contact surface of the guard member being formed of an iron base alloy material having substantial amounts of iron and aluminum, said material of the guard member contact surface having a Vickers hardness which exceeds 300 at room temperature and which exceeds 250 at 200* C. and having a Curie point lower than that of the magnetic alloy material of the head-tips, the alloy material of said guard member contact surface containing about 18 percent to 50 percent by weight of aluminum and having a Curie point lower than room temperature, and the material of the guard member contact surface having similar temperature-hardness characteristics to that of the head-tips under working temperature conditions of the magnetic head.

Claim 17

In a magnetic transducer system, a rotary magnetic head comprising head-tips having a tape contact surface which runs into and out of contact with the magnetic tape at every revolution of the head under working conditions of said rotary magnetic head, and a guard member provided near the head-tips, the guard member having a tape contact surface which is nonmagnetic under working conditions of said head and which extends further than both ends of the tape contact surface of the head-tips in a direction substantially at right angles to the plane of the coupling gap of the head-tips and being disposed substantially flush with the tape contact surface of the head-tips, at least the tape contact surface of the guard member being formed of a material whose Vickers hardness exceeds 300 at room temperature and exceeds 250 at 200* C., the temperature-hardness characteristics of the material of the guard member tape contact surface being similar to those of the head-tips over the temperature range of the tape contact surfaces under working conditions of said rotary magnetic head, said head-tips and guard member tape contact surface both being formed of iron base alloy materials containing substantial amounts of iron and aluminum, the material of the head-tips being of a composition by weight comprising predominately iron and not more than 18 percent aluminum, the material of the guard member tape contact surface being of a composition by weight comprising predominately iron and about 18 percent to 50 percent aluminum and having a Curie point lower than room temperature.

Claim 18

In a magnetic transducer system, a rotary magnetic head comprising head-tips having a tape contact surface which runs into and out of contact with the magnetic tape at every revolution of the head under working conditions of said rotary magnetic head, and a guard member provided near the head-tips, the guard member having a tape contact surface which is nonmagnetic under working conditions of said head and which extends further than both ends of the tape contact surface of the head-tips in a direction substantially at right angles to the plane of the coupling gap of the head-tips and being disposed substantially flush with the tape contact surface of the head-tips, at least the tape contact surface of the guard member being formed of a material whose Vickers hardness exceeds 300 at room temperature and exceeds 250 at 200* C., the temperature-hardness characteristics of the material of the guard member tape contact surface being similar to those of the head-tips over the temperature range of the tape contact surfaces under working conditions of said rotary magnetic head, said head-tips and guard member tape contact surface both being formed of iron base alloy materials containing substantial amounts of iron and aluminum, the material of the head-tips being of a composition by weight comprising predominately iron and not more than 18 percent aluminum, the material of the guard member tape contact surface being of a composition by weight comprising predominately iron and about 18 percent to 50 percent aluminum and having a Curie point lower than room temperature.