Magnetoelastic sensor for characterizing properties of thin-film/coatings

• US 20020166382A1
• Filed: 10/20/2001
• Published: 11/14/2002
• Est. Priority Date: 10/20/2000
• Status: Active Grant

• Current Assignee: University Of Kentucky Research Foundation (University of Kentucky)
• Original Assignee: University Of Kentucky Research Foundation (University of Kentucky)
• Inventors: Schmidt, Stefan, Barrett, Gary, Grimes, Craig A., Bachas, Leonidas G., Kouzoudis, Dimitris
• Granted Patent: US 6,688,162 B2
• Time in Patent Office: Days
• US Class Current: 73/579
• CPC Class Codes: G01N 11/16 by measuring damping effect upon oscillatory body
• CPC Class Codes: G01N 33/4905 Determining clotting time of blood by chemical methods G01N33/86, C12Q1/54
• CPC Class Codes: G01N 9/002 using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis G01N9/34 takes precedence

Abstract

An apparatus for determining elasticity characteristics of a thin-film layer. The apparatus comprises a sensor element having a base magnetostrictive element at least one surface of which is at least partially coated with the thin-film layer. The thin-film layer may be of a variety of materials (having a synthetic and/or bio-component) in a state or form capable of being deposited, manually or otherwise, on the base element surface, such as by way of eye-dropper, melting, dripping, brushing, sputtering, spraying, etching, evaporation, dip-coating, laminating, etc. Among suitable thin-film layers for the sensor element of the invention are fluent bio-substances, thin-film deposits used in manufacturing processes, polymeric coatings, paint, an adhesive, and so on. A receiver, preferably remotely located, is used to measure a plurality of values for magneto-elastic emission intensity of the sensor element in either characterization: (a) the measure of the plurality of values is used to identify a magneto-elastic resonant frequency value for the sensor element; and (b) the measure of the plurality of successive values is done at a preselected magneto-elastic frequency.

Claims

1. An apparatus for determining elasticity characteristics of a thin-film layer, comprising:

a sensor element having a base magnetostrictive element at least one surface of which is at least partially coated with the thin-film layer, said sensor element operatively arranged to vibrate within a time-varying interrogation magnetic field;

a receiver, remote from said sensor element, to measure a plurality of values for magneto-elastic emission intensity of said sensor element to identify a magneto-elastic resonant frequency value for said sensor element; and

whereby using a value for density of the thin-film layer and a value for mass of said base magnetostrictive element and said magneto-elastic resonant frequency value, at least one of the elasticity characteristics is determined.

2. The apparatus of claim 1 wherein said magneto-elastic resonant frequency value corresponds with a relative maximum of said plurality of values for magneto-elastic emission intensity measured;

the elasticity characteristics comprise a modulus of elasticity value for the thin-film layer; and

said base magnetostrictive element is made of an alloy of an element selected from the group consisting of iron, cobalt, samarium, yttrium, gadolinium, terbium, and dysprosium.

3. The apparatus of claim 1 wherein said magneto-elastic emission is an electromagnetic emission, said receiver comprises an electromagnetic pick-up coil, said magnetostrictive element is elongated in shape, and the thin-film layer is selected from the group consisting of a fluent bio-substance, a thin-film deposit for use in a manufacturing process, a polymeric coating, a coating of paint, and a coating of an adhesive.

4. The apparatus of claim 1 wherein said magneto-elastic emission is an acoustic emission, and said receiver comprises an electroacoustic device containing a transducer for operation over a range of frequencies from 1 KHz to 1 GHz, and said magneto-elastic resonant frequency value is an acoustic resonant frequency value.

5. The apparatus of claim 3 wherein a thickness, t_tf, of the thin-film layer is less than a thickness, t_mag, of said base magnetoelastic element and a length, l, of said sensor element is at least twice a width, w, thereof.

6. The apparatus of claim 1 wherein the thin-film layer comprises a fluent bio-substance deposited atop said at least one surface, said fluent bio-substance to comprise a bio-component selected from the group consisting of a biologic agent and blood.

7. The apparatus of claim 1 wherein the said magnetostrictive element is a micro-element made of a ferrous alloy;

and further comprising a processor for determining the elasticity characteristics which comprises a modulus of elasticity value, Y_c, for the thin-film layer, according to the expression;

8. The apparatus of claim 1 wherein said receiver comprises an electromagnetic pick-up coil, said time-varying interrogation magnetic field comprises a pulse, said measure is performed after said time-varying magnetic field pulse is transmitted, said magneto-elastic emission is an electromagnetic emission, said magnetostrictive element is ribbon shaped and made of an alloy.

9. The apparatus of claim 1 wherein said receiver comprises an electromagnetic pick-up coil, and further comprising:

a processor for determining the elasticity characteristic;

a field generating coil, remote from said receiver pick-up coil, for generating said time-varying interrogation magnetic field; and

a receptacle for accepting said sensor element when so determining.

10. An apparatus for determining elasticity characteristics of a thin-film layer of a fluent bio-substance, comprising:

a sensor element having a base magnetostrictive element at least one surface of which is at least partially coated with the thin-film layer, said sensor element operatively arranged to vibrate within a time-varying interrogation magnetic field;

a receiver, remote from said sensor element, to measure a plurality of successive values for magneto-elastic emission intensity of said sensor element at a preselected magneto-elastic frequency; and

whereby using said values for emission intensity, an elasticity response profile for the bio-substance is produced.

11. The apparatus of claim 10 wherein an identified magneto-elastic resonant frequency value for said sensor element is used to identify said preselected magneto-elastic frequency, said measure of said plurality occurs over a response-time interval, and said elasticity response profile comprises a coagulation reaction curve for the bio-substance.

12. The apparatus of claim 10 further comprising a receptacle for accepting said base magnetostrictive element such that said element has at least one free-end;

and wherein;

the fluent bio-substance comprises a drop of blood;

said blood is deposited atop said at least one surface nearby said free-end; and

using said elasticity response profile, a blood clotting time is determined.

13. The apparatus of claim 10 wherein:

said receiver comprises a device selected from the group consisting of an electromagnetic pick-up coil and an electroacoustic device;

the fluent bio-substance comprises a bio-component selected from the group consisting of a biologic agent and blood; and

said elasticity response profile comprises a bioactive reaction response curve for the bio-substance.

14. The apparatus of claim 10 wherein said receiver comprises an electromagnetic pick-up coil, and further comprising:

a processor for producing said elasticity response profile;

said preselected magneto-elastic frequency is a resonant frequency value for said sensor element;

a field generating coil, remote from said receiver pick-up coil, for generating said time-varying interrogation magnetic field; and

a receptacle for accepting said sensor element when so producing.

15. The apparatus of claim 10 wherein said elasticity response profile comprises a coagulation reaction curve represented by a plurality of successive voltage values respectively associated with said plurality of successive values for magneto-elastic emission intensity measured, plotted against time over a selected response-time interval.

17. The method of claim 16 wherein:

said emission is selected from the group consisting of an electromagnetic emission and an acoustic emission;

said step of remotely measuring comprises receiving with a remote receiver selected, respectively, from the group consisting of a pick-up coil and an electroacoustic device; and

said step of determining the elasticity characteristic comprises finding a modulus of elasticity value for the thin-film layer.

18. The method of claim 16 wherein said operatively arranging comprises arranging said sensor element within a receptacle;

and step of determining the elasticity characteristic comprises finding a modulus of elasticity value for the thin-film layer, said thin-film layer selected from the group consisting of a fluent bio-substance, a thin-film deposit for use in a manufacturing process, a polymeric coating, a coating of paint, and a coating of an adhesive.

19. The method of claim 16 wherein said step of determining the elasticity characteristic comprises finding a modulus of elasticity value, Y_c, for the thin-film layer, according to the expression:

16. A method for determining elasticity characteristics of a thin-film layer at least partially coating a surface of a base magnetostrictive element, comprising the steps of:

applying a time-varying interrogation magnetic field to a sensor element comprising the base magnetostrictive element and thin-film layer, operatively arranged to vibrate in response to said interrogation magnetic field;

remotely measuring a plurality of values for magneto-elastic emission intensity of said sensor element to identify a magneto-elastic resonant frequency value therefor; and

using a value for density of the thin-film layer and a value for mass of the base magnetostrictive element and said magneto-elastic resonant frequency value, determining at least one of the elasticity characteristics.

20. A method for determining elasticity characteristics of a thin-film layer of a fluent bio-substance at least partially coating a surface of a base magnetostrictive element, comprising the steps of:

applying a time-varying interrogation magnetic field to a sensor element comprising the base magnetostrictive element and thin-film layer, operatively arranged to vibrate in response to said interrogation magnetic field;

remotely measuring, over a response-time interval, a plurality of successive values for magneto-elastic emission intensity of said sensor element at a preselected magneto-elastic frequency; and

using said values for emission intensity, producing an elasticity response profile for the bio-substance.

21. The method of claim 20 wherein:

said emission comprises an electromagnetic emission;

said step of remotely measuring comprises receiving with a pick-up coil not in direct electrical connection with said sensor element;

said step of remotely measuring further comprises using a magneto-elastic resonant frequency value identified for said sensor element to identify said preselected magneto-elastic frequency; and

said elasticity response profile comprises a coagulation reaction curve for the bio-substance.

22. The method of claim 20 wherein:

said emission comprises an acoustic emission;

said step of remotely measuring comprises receiving with an electroacoustic device containing a transducer not in direct electrical connection with said sensor element;

said step of producing an elasticity response profile comprises displaying a bioactive reaction response curve for the bio-substance.

23. The method of claim 20 wherein said step of producing an elasticity response profile comprises representing a coagulation reaction curve by plotting a plurality of successive voltage values respectively associated with said plurality of successive values for magneto-elastic emission intensity measured, against time over a selected response-time interval.

24. The method of claim 20 wherein said operatively arranging comprises arranging said sensor element within a receptacle such that said element has at least one free-end;

the fluent bio-substance comprises a bio-component selected from the group consisting of a biologic agent and blood; and

said step of using said values for emission intensity further comprises determining a blood clotting time; and

further comprising the step of depositing the fluent bio-substance atop said surface nearby said free-end.