Abstract: A method to determine deposits in a steam generator having the steps of creating a calibration standard having at least two rings of deposit material, subjecting the calibration standard to an eddy current signal, wherein an amplitude of the signal reflected from the calibration standard is used to obtain a polynomial equation fit of the reflected eddy current signals to actual thickness of the rings, obtaining a steam generator with tubes, initiating an eddy current signal into the tubes of the steam generator, detecting and recording reflections of the eddy current signal initiated into the tubes of the steam generator, and determining a thickness of the deposits in the steam generator from the recorded reflections of the eddy current signal and the polynomial equation.

Abstract: A semiconductor processing system is provided. The semiconductor processing system includes a first sensor configured to isolate and measure a film thickness signal portion for a wafer having a film disposed over a substrate. A second sensor is configured to detect a film thickness dependent signal in situ during processing, i.e. under real process conditions and in real time. A controller configured to receive a signal from the first sensor and a signal from the second sensor. The controller is capable of determining a calibration coefficient from data represented by the signal from the first sensor. The controller is capable of applying the calibration coefficient to the data associated with the second sensor, wherein the calibration coefficient substantially eliminates inaccuracies introduced to the film thickness dependent signal from the substrate. A method for calibrating an eddy current sensor is also provided.

Abstract: A measuring device and method are disclosed for parameter distribution measurement over the entire surface of sheet-like objects. The parameters of primary interest are thickness and permeability profiles. The device includes a parameter measuring unit a coordinate measuring unit and a synchronization unit to control operation of the parameter measuring unit and the coordinate measuring unit. The coordinate measuring unit determines the measuring device position on two-dimensional surface using image correlation analysis. The measuring device further comprises a platform for its movement in the plane of the sheet-like object.

Abstract: With a method for the contactless determination of a thickness of a layer (20) made of electrically-conductive material of a component (17), a sensor composed of a coil form (13) and a coil (14) is positioned in the vicinity of the component (17) to be measured. The method is based on a combination of the principles of induction and eddy current. The thickness of the layer (20) is determined using a plurality of measuring and evaluation steps in which the coil (14) is acted upon with a first alternating current frequency f1 and a second alternating current frequency f2, and its change in inductance is evaluated. The distance between the coil form (13) and, therefore, the coil (14), and the component (17) is derived from the inductance value of the coil (14) acted upon with the second alternating current frequency f2.

Abstract: A method of determining a thickness at a thickness position of a conductive film on a substrate with a center zone and an edge zone is disclosed. The method includes providing a set of thickness correlation curves at a set of sensor position radii from a center of the substrate to a position where a sensitivity of an eddy current sensor to the edge zone is greater than zero. The method also includes measuring a set of eddy current responses at a sensor position of the set of sensor position radii. The method further includes correlating the set of eddy current responses to the thickness at the thickness position.

Abstract: Methods are provided for calibrating a tool using an eddy current probe and calibration wafers that each have a measurable predetermined property and a measurement of the measurable predetermined property of a first calibration wafer is different than a measurement of the measurable predetermined property of a second calibration wafer. The methods include determining a first set of impedance measurements of the calibration wafers while each is disposed in the tool and the tool has a tool parameter that is at a first condition, collecting a second set of impedance measurements of the calibration wafers while each is disposed in the tool and the tool parameter is at a second condition, establishing a reference point, based upon a first and a second data point from the first set of impedance measurements and a first and a second data point from the second set of impedance measurements.

Abstract: A semiconductor device having a measuring pattern that enhances measuring reliability and a method of measuring the semiconductor device using the measuring pattern. The semiconductor device includes a semiconductor substrate having a chip area in which an integrated circuit is formed, and a scribe area surrounding the chip area. The semiconductor device also includes a measuring pattern formed in the scribe area and having a surface sectional area to include a beam area in which measuring beams are projected, and a dummy pattern formed in the measuring pattern to reduce the surface sectional area of the measuring pattern. The surface sectional area of the dummy pattern occupies from approximately 5% to approximately 15% of a surface sectional area of the beam area.

Abstract: A method and apparatus are provided for measuring a thickness of a nonconductive coating disposed over portions of first and second conductive surfaces that intersect at an intersection angle. The apparatus is a thickness measurement gauge having an eddy current sensor. The thickness measurement gauge includes an eddy current sensor and electronic analyzer. The thickness gauge may be provided with a pressure enclosure. A method of calibrating a thickness measurement gauge and a calibration stand are also provided. The calibration stand has third and fourth conductive surfaces intersecting at the intersection angle. The conductivities of the third and fourth surfaces correspond to the conductivities of the first and second surfaces.

Abstract: A sensor device includes the ability to determine part presence and at least one physical characteristic of the part. A drive coil and sense coil are arranged so that a voltage applied across the drive coil causes a response in the sense coil, which is influenced by the presence of the item of interest. In a first mode, a controller determines whether the item is present by determining an amount of coupling between the drive coil and the sense coil, which is indicative of whether a part is present near the sense coil. In a second mode, the controller determines an amount of magnetic flux that is indicative of a thickness of the material. In another mode, constant current applied to the drive coil instigates a voltage across both coils. The amplitude of the sense coil voltage and a phase shift of the sense coil voltage relative to the drive coil voltage provides material thickness information.

Abstract: Improving reducing or eliminating the effects of variation in characteristics of the resonance circuit in a resonance type displacement detection apparatus, so as to improve displacement detection accuracy. In a displacement detection system 10, the resonance frequency range assumable by the resonance circuit 21 is estimated in advance, there is determined a drive frequency variation range f1–f2 such that the estimated resonance frequency range is included therein, and by means of a variable oscillator 30, drive frequency is repeatedly varied between the first frequency f1 and the second frequency f2. Accordingly, where the resonance frequency of the resonance circuit 21 is fr1, when the drive frequency has changed to fr1, resonance voltage Vgl1 may be obtained in the case of large gap G. Where the resonance frequency of the resonance circuit 21 is fr2, when the drive frequency has changed to fr2, resonance voltage Vgl2 may be obtained in the case of large gap G.

Abstract: A method and an apparatus for enhancement of the for measuring resistance-based features of a substrate is provided. The apparatus includes a sensor configured to detect a signal produced by a eddy current generated electromagnetic field. The magnetic field enhancing source is positioned to the alternative side of the object under measurement relative to the sensor to enable the sensitivity enhancing action. The sensitivity enhancing source increases the intensity of the eddy current generated in the object under measurement, and as a result the sensitivity of the sensor. A system enabled to determine a thickness of a layer and a method for determining a resistance-based feature characteristic are also provided.

Abstract: An apparatus for indicating the wall thickness of a cored welding wire traveling in a given path to determine the percentage of volume of fill. This apparatus comprises a first induction coil surrounding the path; a source of AC current connected across the coil; a second reference coil connected to the AC source where the second reference coil surrounds a fixed section of cored welding wire with a desired wall thickness, and an output device indicating deviation of the wall thickness of the traveling wire from the wall thickness of the fixed section of wire by detecting the inductive reactance of the first coil compared to the second coil.

Abstract: A method for monitoring an inspection sample includes generating inspection data comprising resistance and reactance measurements that are obtained from an inspection sample having a conductive layer of unknown thickness. Calibration data is used for estimating the thickness of the conductive layer of the inspection sample. This calibration data includes resistance and reactance measurements obtained from one or more calibration samples, each calibration sample having a conductive layer of known thickness. The conductive layers of the inspection sample and the calibration samples comprise different materials having a known conductive relationship.

Abstract: This invention pertains to a method and apparatus for determining the thickness of a ferromagnetic or paramagnetic material when only one side of the material is accessible. In one embodiment, the invention provides a method for engaging a constant signal with the ferromagnetic material for inducing a changed signal, generating a stepped saturation signal over a range of currents for engagement with the ferromagnetic material, detecting the changed signal as the saturation signal is varied over the range of currents, determining the relationship between the changed signal and the stepped saturation signal, and evaluating the thickness of the material based upon the relationship between the changed signal and the stepped saturation signal.

Abstract: Improved endpoint detection and/or thickness measurements may be obtained by correcting sensor data using calibration parameters and/or drift compensation parameters. Calibration parameters may include an offset and a slope, or other parameters. Drift compensation parameters may include off-wafer measurements.

Abstract: The invention is a process for determining the resistivity of a layered structure including a layer of resistive material hidden under a topcoat and a tile layer, the process comprises the steps of; 1) directing electromagnetic radiation over a selected frequency range to the outer surface of the layered structure; 2) measuring the reflection of the electromagnetic radiation from the layered structure surface; 3) converting the signal into the time domain; 4) analyzing the first echo to obtain the topcoat thickness; 5) obtaining the tile thickness from the time delay between the first and second echoes; 6) compensating the second echo with electromagnetic power loss due to the topcoat and tile; and 7) determining the resistance of the resistive layer from the compensated second echo.

Abstract: The invention relates to a measurement probe, in particular for an apparatus for measurement of the thickness of thin layers, having a housing which has at least one printed circuit board and at least one sensor element which is associated with the printed circuit board, and having a contact cup which is arranged at the lower end of the housing, characterized in that a flexible strip, which has at least one connecting line, is provided on the at least one printed circuit board, and which is passed out of the housing.

Abstract: The calibration of a laser caliber is described. The laser caliber uses first and second sensors to determine the distance to different sides of a sheet. A third sensor is used to determine the distance between the first and second sensors. The calibration of the first, second, and third sensors is done by positioning a test object onto the platform sensed by the third sensor. The platform is moved to multiple positions in order to calibrate the first, second and third sensors. Since the displacement of the platform moves the distance to the target of the first, second and third sensors the same amount, the sensors can be accurately calibrated for a number of different positions of the test object. A very accurate calibrating displacement measuring device such as an LVDT can be used.

Abstract: A sensor device includes the ability to determine part presence and at least one physical characteristic of the part. A drive coil and sense coil are arranged so that a voltage applied across the drive coil causes a response in the sense coil, which is influenced by the presence of the item of interest. In a first mode, a controller determines whether the item is present by determining an amount of coupling between the drive coil and the sense coil, which is indicative of whether a part is present near the sense coil. In a second mode, the controller determines an amount of magnetic flux that is indicative of a thickness of the material. In another mode, constant current applied to the drive coil instigates a voltage across both coils. The amplitude of the sense coil voltage and a phase shift of the sense coil voltage relative to the drive coil voltage provides material thickness information.

Abstract: Methods and systems for monitoring semiconductor fabrication processes are provided. A system may include a stage configured to support a specimen and coupled to a measurement device. The measurement device may include an illumination system and a detection system. The illumination system and the detection system may be configured such that the system may be configured to determine multiple properties of the specimen. For example, the system may be configured to determine multiple properties of a specimen including, but not limited to, a property of a specimen prior to, during, or subsequent to an etch process. In this manner, a measurement device may perform multiple optical and/or non-optical metrology and/or inspection techniques.

Abstract: An inductive bridge circuit using mutual inductances to transform impedances is used for detection of wall-thinning defects in metals. The bridge circuit has a first test coil placed adjacent to a good metal section and a second test coil placed adjacent to a metal to be tested. The bridge circuit compares the inductance in the first coil and inductance in the second test coil to compare wall thinning defects. The apparatus may also include first and second measuring transformers which are connected between the bridge circuit and the test coils where the transformers provide for impedance matching and reduced current requirements in the bridge. The circuit may also include one or more potentiometer circuits connected across the bridge which are used for compensating for imbalance of impedance between the first and second test coils when the coils both have known good metal sections adjacent to them.

Abstract: A method and system are presented for measuring in an electrically conductive film of a specific sample including data indicative of a free space response of an RF sensing coil unit to AC voltage applied to the RF sensing coil. The sensing coil is located proximate to the sample at a distance h substantially not exceeding 0.2 r wherein r is the coil radius; an AC voltage in a range from 100 MHz to a few GHz is applied to the sensing coil to cause generation of an eddy current passage through the conductive film; a response of the sensing coil to an effect of the electric current through the conductive film onto a magnetic field of the coil is detected and the measured data indicative of the response is generated. The thickness of the film is determined by utilizing the data indicative of the free space measurements to analyze the measured date. The method thus provides for measuring in conductive films with a sheet resistance Rs in a range from about 0.009 to about 2 Ohm/m2.

Abstract: An eddy current detector includes two poles aligned in the direction of extension of partitions located behind a wall, wherein the thickness must be measured, but which interfere with the measurements. The influence of the partitions is decreased by the core of the detector including two poles aligned in the direction of the extension of the partitions and by using a logical system to correct the results obtained according to preliminary results obtained on a reference surface.

Abstract: A measuring gage for determining the thickness of a non-metallic material utilizes an inductive sensor positioned on one side of the material to be measured and a metallic object placed on the opposite side. The output of the sensor is used to determine the distance between the sensor and the metallic object, and hence the thickness of the material. The movement of the sensor and the metallic object can be computer controlled to map the thickness of the material along a predetermined path and produce a cross-sectional thickness profile. The output of the sensor can be used in conjunction with a computer controller responsible for adjusting the size of a score line to prepare an airbag deployment section in a vehicle trim panel.

Abstract: A method for the nondestructive measurement of the thickness of thin layers having a probe, having a first coil device on an inner core, the geometrical center of which coil device and the geometrical center of at least one second coil device coincide, the at least one second coil device partially surrounding the first coil device, and an evaluation unit, to which signals of the coil devices are emitted during a measurement for ascertaining the layer thickness. A circuit is provided, by which the first and the at least one second coil devices are excited sequentially during a measurement.

Abstract: A method for monitoring wall thickness of an object having an electrically conductive wall, using a pulsed eddy current probe comprising a transmitter means and a receiver means, which method comprises selecting an inspection location on the wall; at a plurality of inspection times &thgr;m (m=2, . . . ,M), arranging the probe in a predetermined position relative to the inspection location, inducing transient eddy currents in the object by activating the transmitter means, recording signals Vm with the receiver means; determining, for each inspection time &thgr;m, a temperature Tm indicative of the temperature of the object at the inspection location; and determining, from each of the signals Vm, a wall thickness dm pertaining to inspection time &thgr;m, wherein the temperature Tm is taken into account.

Abstract: The present invention includes capacitive film thickness measurement devices and measurement systems. The invention also includes machines or instruments using those aspects of the invention. The present invention additionally includes methods and procedures using those devices of the present invention. The present invention discloses a capacitance measurement device and technique useful in determining lubricant film thickness on substrates such as magnetic thin-film rigid disks. Using the present invention, variations in lubricant thickness on the Angstrom scale or less may be measured quickly and nondestructively.

Abstract: An electric current comprising a plurality of harmonic components is passed through the pipe under test, a magnetic field produced by it outside the pipe is measured, a spectrum of the electric current is measured, a spectrum from measured magnetic field data is also obtained. The ratios between identical spectral components of the current and magnetic field are evaluated. The test apparatus comprises a current source supplying an electric current, a means for measuring and storing momentary current values, a means for evaluating a current spectrum to define harmonic components of the electric current, at least one magnetic field sensor for measuring and storing momentary values of the magnetic field produced outside the pipe by the current, a means for evaluating the magnetic field spectrum to define harmonic components of the magnetic field, and a means for comparing and analyzing the obtained spectral data of the current and magnetic field.

Abstract: The present invention includes capacitive film thickness measurement devices and measurement systems. The invention also includes machines or instruments using those aspects of the invention. The present invention additionally includes methods and procedures using those devices of the present invention. The present invention discloses a capacitance measurement device and technique useful in determining lubricant film thickness on substrates such as magnetic thin-film rigid disks. Using the present invention, variations in lubricant thickness on the Angstrom scale or less may be measured quickly and nondestructively.

Abstract: Device for detecting electro-magnetically the level of a material which is conductive, or made conductive, particularly molten glass.

Abstract: The invention relates to a method for carrying out nondestructive testing of a gas turbine blade during which corrosion areas, which are located near the surface and which consist of oxidized carbides or of base material that is sulfidized near the surface, are determined by means of an eddy current measurement. As a result, the blades can be ground or sorted, in particular, before subjecting the gas turbine to a complicated cleaning and coating process.

Abstract: An unintentionally overlapped condition in a paper sheet being transported is detected by making ultrasonic waves incident on its path and detecting a phase difference between the received ultrasonic waves and a predetermined standard phase. For detecting an overlap on the basis of this phase difference, a specified data item on the detected overlap such as a cumulative number of times an overlap has been detected is generated and one of a plurality of preliminarily defined levels corresponding to this specified data item is selected. The selected level is outputted. If the overlap is detected over an entire detection range of the paper sheet from its front edge to the back edge, however, it is concluded that there is no possibility of an unintentional overlap.

Abstract: A monitoring device is for monitoring changes in at least one characteristic of a coating, and uses an electromagnetic field generator, a magnetic field sensor positioned within the magnetic field of the field generator and a signal generator for generating an alternating signal of a selected frequency for driving the magnetic field generator. The selected frequency causes resonant fields to be generated within a coating sample to be monitored, thereby altering the magnetic field detected by the magnetic field sensor. The magnetic field sensor output is monitored over time, and this enables changes in at least one characteristic of the sample to be monitored over time. This device detects magnetic resonance within a sample as a tool for analysing the characteristics of the sample. In this way, the curing characteristics of the sample can be evaluated by monitoring the concentration of the selected component over time.

Abstract: A device for measuring thin films and bulks is disclosed using slow-wave structures in electrodynamic elements to allow a decrease in frequency, an increase in sensitivity to electromagnetic parameters and accuracy of their monitoring. A method is also disclosed for monitoring of materials which includes placing an electrodynamic element near a monitored material and exciting an alternating electromagnetic field at an appropriate frequency to penetrate the monitored material concentrating in a small volume. Electromagnetic field parameters are then measured which are caused by the material parameters variation and said variations are converted to electromagnetic field parameters, the element being excited by an electromagnetic field in the form of at least one slowed electromagnetic wave.

Abstract: A method for non-contact measurement of dimensions such as thickness or diameter and electrical characteristics of an electrically conductive object (6) based on electromagnetic induction and a time-varying magnetic field. A substantially constant current is supplied to at least one transmitter coil (3) such that an electromagnetic field penetrates the object (6). Current to the transmitter coil (3) is cut off and a voltage induced in at least one receiving coil (8) by at least one decaying magnetic field. The voltage in receiving coil (8) is measured from a first time following decay of a magnetic field in the air (T3) until a time when the field has decayed to zero (T4, T5, T6) and the signal is integrated. A value for a physical dimension of the object (6) is calculated from this integral. The method is accurate, undisturbed by surface contamination or object movement, and applicable to different geometric forms including plate, bar or tube.

Abstract: A method of determining the level of a medium in a container by generating a constant magnetic field in the container, exciting an elongated sensor element to longitudinal oscillations, the sensor element being secured on one end in the container and containing a magnetostrictive material, measuring the resonant frequency of the sensor element, or the damping of the longitudinal oscillation, by means of periodically varying magnetization of the sensor element in the constant magnetic field, and determining the fill level from the resonant frequency or from the damping of the longitudinal oscillations.

Abstract: A method for estimating a thickness profile of a substrate sample that has undergone a chemical-mechanical polishing (CMP) process includes obtaining initial and terminating resistance and reactance measurements from the sample. Initial eddy current measurement values are obtained while an eddy current probe is positioned at an initial distance relative to the substrate sample, and terminating values are obtained while the eddy current probe is positioned at a modified distance relative to the sample. An intersecting line can be calculated using the initial and terminating resistance and reactance measurements. An intersecting point between a previously defined natural intercepting curve and the intersecting line may also be determined. A reactance voltage of the intersecting point may be located along a digital calibration curve to identify a closest-two of a plurality of calibration samples.

Abstract: An electric current comprising a plurality of harmonic components is passed through the pipe under test, a magnetic field produced by it outside the pipe is measured, a spectrum of the electric current is measured, a spectrum from measured magnetic field data is also obtained. The ratios between identical spectral components of the current and magnetic field are evaluated. The test apparatus comprises a current source supplying an electric current, a means for measuring and storing momentary current values, a means for evaluating a current spectrum to define harmonic components of the electric current, at least one magnetic field sensor for measuring and storing momentary values of the magnetic field produced outside the pipe by the current, a means for evaluating the magnetic field spectrum to define harmonic components of the magnetic field, and a means for comparing and analyzing the obtained spectral data of the current and magnetic field.

Abstract: A sensor for monitoring a conductive film in a substrate during chemical mechanical polishing generates an alternating magnetic field that impinges a substrate and induces eddy currents. The sensor can have a core, a first coil wound around a first portion of the core and a second coil wound around a second portion of the core. The sensor can be positioned on a side of the polishing surface opposite the substrate. The sensor can detect a phase difference between a drive signal and a measured signal.

Abstract: An eddy current detector (4) comprises two poles aligned in the direction of extension of partitions (3) located behind a wall (2) wherein the thickness must be measured, but which interfere with the measurements. The influence of the partitions (3) is decreased if the core (6) of the detector (4) comprises two poles aligned in the direction of the extension of the partitions (3) and if a logical system is used to correct the results obtained according to preliminary results obtained on a reference surface.

Abstract: A sensor device includes the ability to determine part presence and at least one physical characteristic of the part. A drive coil and sense coil are arranged so that a voltage applied across the drive coil causes a response in the sense coil, which is influenced by the presence of the item of interest. In a first mode, a controller determines whether the item is present by determining an amount of coupling between the drive coil and the sense coil, which is indicative of whether a part is present near the sense coil. In a second mode, the controller determines an amount of magnetic flux that is indicative of a thickness of the material. In another mode, constant current applied to the drive coil instigates a voltage across both coils. The amplitude of the sense coil voltage and a phase shift of the sense coil voltage relative to the drive coil voltage provides material thickness information.

Abstract: Measuring the wall thickness of an electrically conductive object using a probe comprising a transmitter coil, a first receiver and a second receiver, which method comprises arranging the probe near the object; inducing transient eddy currents in the object and recording the signals of the receivers with time; measuring the wall thickness from a characteristic of one of the signals; calculating a characteristic value from a combination of the signals; and correcting the measured wall thickness for the distance between the probe and the object using a pre-determined relationship between the wall thickness and the characteristic value for different values of the distance between the probe and the object.

Abstract: An apparatus for and a method of measuring material thickness with magnetics. The thickness monitoring system includes a thickness monitor, a probe, and a target. In a preferred embodiment, the probe is positioned on one side of an article for which the thickness is to be determined. The target is positioned on the opposite side of the article from the probe. The probe includes an excitation coil, a field compensation coil, and a magnetic sensor. The method includes energizing the excitation coil to excite a response from the target, compensating for the effect of the excitation coil on the magnetic sensor, measuring the response of the target with the magnetic sensor, and determining the thickness of the article from the measured response. The preferred mode of energizing the excitation coil is with an AC waveform; however DC, multi-frequency AC, or a combination of AC and DC waveforms may be used.

Abstract: A thickness measuring system comprises: an eddy current loss measuring sensor having an exciting coil for receiving a high frequency current to excite a high frequency magnetic field to excite an eddy current in a conductive film, and a receiving coil for outputting the high frequency current which is influenced by an eddy current loss caused by the eddy current; an impedance analyzer for measuring the variation in impedance of the eddy current loss measuring sensor, the variation in current value of the high frequency current or the variation in phase of the high frequency current on the basis of the high frequency current outputted from the receiving coil; an optical displacement sensor for measuring the distance between the conductive film and the eddy current loss measuring sensor; and a control computer including a thickness calculating part for calculating the thickness of the conductive film on the basis of various measured results of the impedance analyzer and optical displacement sensor, and the eddy

Abstract: A reference standard and method for inspecting dual-layered coatings. The reference standard has a first layer adherent to a substrate, the first layer has a predetermined thickness that increases in one direction. Adherent to the first layer is a second layer, the second layer has a predetermined thickness that increases in a direction orthogonal with the first layer. The orientation of the first and second layers of the reference standard provides a spectrum of the possible variations of the dual-layered coating.

Abstract: A method for identifying metal layer thickness of an inspection sample according to one embodiment utilizes an eddy current probe to obtain initial resistance and reactance measurements from the inspection sample. Once these measurements have been obtained, the relative distance between the eddy current probe and inspection sample is increased and terminating resistance and reactance measurements are obtained. An inspection sample intersecting line may then be calculated using the initial and terminating resistance and reactance measurements. An intersecting point between a natural intercepting curve and the inspection sample intersecting line may also be determined. A reactance voltage of the intersecting point along a digital calibration curve is calculated to identify a closest two of a plurality of calibration samples. The metal layer thickness of the inspection sample may then be calculated by performing an interpolation between the identified closest two calibration samples.

Abstract: In a method and device for measuring at least one parameter of a metal bed, measuring is obtained by a magnetic field being generated from one side of the metal bed so that eddy currents are generated in the metal bed as the metal bed moves relative to the magnetic field. The metal bed and the magnetic field are made to move relative to one another. A force related to the eddy currents affects a body and the action of the force on the body is detected by a detecting device, the detected force being a function of a desired parameter of the metal bed.

Abstract: A nondestructive method for determining the thickness of a metallic protective layer determined by detection of a different type of intervening layer which is situated between the metallic protective layer and the metallic base material, by ultrasound, eddy-current or (pulsed) thermography. The intervening layer may comprise a nonmetallic layer of oxides or carbides, a metallic layer of pure nickel or a layer with depleted Al and Ti content in that region of the base material which is close to the surface. This method can be used for turbine blades in order to determine the layer thickness, for example during the test phase of coating, and to avoid the known destruction of the turbine blade, which is labor- and cost-intensive.

Abstract: A self referencing eddy current probe for determining conductive coating thickness includes a housing having a reference sample area, for accommodating a reference sample, and a testing edge, for positioning on a component during a coating thickness measurement. The eddy current probe further includes a reference eddy current coil situated in the housing adjacent to the reference sample area and a test eddy current coil, which is located at the testing edge. A self referencing eddy current measurement system, for measuring a thickness of a conductive coating on a component, includes the self referencing eddy current probe. The system further includes a signal generator for energizing the test and reference coils and a comparison module for comparing a test signal received from the test coil and a reference signal received from the reference coil and outputting a compared signal.

Abstract: A pair of elastic strips are provided in order to hold sheet material to be measured in thickness. Each of the elastic strips includes of one or more elastic films. Ends of the elastic strips are supported by support portions, and the other ends of the elastic strips are provided with respective coils, opposed to push each other, and kept in contact with each other. When the sheet material is held between support portions, the inductances of the coils are changed and the thickness of the sheet material is detected as an electric signal representative of the changed inductance.