Magnetic inspection probe for measurement of magnetic anisotropy
AssigneeIowa State University Research Foundation, Inc.
InventorsDavid C. Jiles, Michael K. Devine
Life of this patent
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Abstract
A magnetic inspection probe for use in the planar measurement of magnetic properties in two or more defined directions. The inspection probe includes a cup-shaped outer body, a centrally disposed central core, a field generating power coil, a flux coil for measuring magnetic induction and a plurality of field detection elements disposed in various known orientations. In use, the inspection probe of the present invention permits the detection and measurement of anisotropy of material characteristics in at least two directions across the plane of measurement.
Claims15
A magnetic inspection probe for measuring the magnetic properties of an anisotropic test specimen by making magnetic measurements in at least two directions oriented in a known manner to one another across the surface of the test specimen without the need to reorient the probe, the inspection probe comprising:
- the probe having a body and core of respectively different shapes oriented to create a two-dimensional multi-directional magnetic field therebetween for introducing the magnetic field into the test specimen;
- means for measuring the magnetic flux within the test specimen resulting from the introduction of the magnetic field;
- and
- at least two sensor means in the probe oriented in different directions with respect to each other for measuring simultaneously in two or more directions of the two-dimensional magnetic field, without reorientation of the probe, the magnetic field intensity adjacent to the surface of the test specimen caused by the introduction of the magnetic field into the specimen.
A magnetic inspection probe for measuring the magnetic properties of an anisotropic test specimen by making magnetic measurement in at least two directions without the need to reorient the probe comprising:
- a cylindrical cup-shaped outer body;
- a solid cylindrical core centrally disposed within the cup-shaped outer body;
- the core and cup defining a plane for contact with the test specimen;
- power coil means disposed about the cylindrical core for generating a uniform radial magnetic field for coupling into the test specimen;
- flux coil means disposed about the cylindrical core for measuring the magnetic flux density of the test specimen;
- and
- two Hall probes disposed in two directions between the cylindrical core and the outer body adjacent to the surface of the test specimen for simultaneously measuring the field intensity in said two directions without reorienting the probe.
A method for determining in-plane anisotropy in magnetic properties across the surface of a test specimen comprising the steps of:
- (a) positioning a magnetic probe adjacent to the surface of the test specimen, the probe having a body and core of respectively different shapes oriented to produce a two-dimensional multi-directional magnetic field therebetween;
- (b) energizing the probe to introduce the two-dimensional magnetic field into the surface of the test specimen;
- (c) measuring via the probe the magnetic flux in the specimen;
- (d) measuring using at least two sensors in the probe, the intensity of the magnetic field caused by the introduction of the magnetic field into the specimen, the measuring step being performed adjacent to the surface of the test specimen simultaneously in two or more directions which are oriented to one another in a known manner while maintaining the magnetic probe in a stationary position;
- (e) altering the intensity of the magnetic field introduced in step b;
- (f) repeating steps c and d for each change in the magnetic field intensity;
- and
- (g) determining the values of physical properties occurring in the directions of measurement based on the measurements of magnetic flux and field intensity adjacent to the surface of the test specimen.
A method for determining in-plane anisotropy in magnetic properties across the surface of a test specimen comprising the steps of:
- positioning a magnetic probe on the surface of the specimen the probe having a body and core of respectively different shapes oriented to produce a two-dimensional multi-directional magnetic field therebetween;
- energizing the probe to produce the two directional magnetic field and coupling the magnetic field into the surface of the test specimen via the probe;
- measuring, using the probe, the magnitude of the magnetic flux introduced into the specimen;
- measuring, using at least two sensors in the probe, and without reorientation of the probe, the intensity of the resultant magnetic field adjacent to the surface of the test specimen in at least two directions orientated in a predetermined relationship with respect to each other;
- and
- utilizing the flux measurements and field measurements to determine directionally varying magnetic properties to characterize the anisotropy in the magnetic properties.
Dependencies are inferred from the claim text.