Embodiments of the invention relate to polycrystalline diamond (PCD) exhibiting enhanced diamond-to-diamond bonding. In an embodiment, PCD includes a plurality of diamond grains defining a plurality of interstitial regions. A metal-solvent catalyst occupies at least a portion of the plurality of interstitial regions. The plurality of diamond grains and the metal-solvent catalyst collectively exhibit a coercivity of about 115 Oersteds (Oe) or more and a specific magnetic saturation of about 15 Gauss.Math.cm.sup.3/grams (G.Math.cm.sup.3/g) or less. Other embodiments are directed to polycrystalline diamond compacts (PDCs) employing such PCD, methods of forming PCD and PDCs, and various applications for such PCD and PDCs in rotary drill bits, bearing apparatuses, and wire-drawing dies.

A surface property evaluation method includes a measurement step for acquiring the distribution of impedance in the depth direction of a test piece, and an evaluation step for evaluating the surface treatment state in the depth direction and wherein the evaluation step includes: a step for creating a reference measurement value group by preparing untreated sample, good sample, and sample to be evaluated, and calculating an impedance ratio 1 at each frequency for the untreated sample and good sample impedances; a step for creating an evaluation measurement value group by calculating an impedance ratio 2 for the impedances of untreated sample at each frequency relative to the sample to be evaluated impedances; and a step for evaluating the surface treatment state of a sample to be evaluated by comparing a reference measurement value group with the evaluation measurement value group.

To provide a surface property inspection sorting apparatus, system, and method capable of efficiently performing steps to evaluate the surface properties of spring-shaped members. A surface property inspection and sorting apparatus 1 includes a surface property inspection device, a measuring member for measuring the surface properties of the spring-shaped members M, and a sorting means for sorting the spring-shaped members into good and bad parts. The measuring member is constituted so that spring-shaped members can pass through an inspection detector, and the surface properties of the spring-shaped member can be evaluated and a pass/fail judgment made by a surface property inspection device based on output signals output from an AC bridge circuit while the spring-shaped member passes through the inspection detector.

To provide a surface property inspection sorting apparatus, system, and method capable of efficiently performing steps to evaluate the surface properties of spring-shaped members. A surface property inspection and sorting apparatus 1 includes a surface property inspection device, a measuring member for measuring the surface properties of the spring-shaped members M, and a sorting means for sorting the spring-shaped members into good and bad parts. The measuring member is constituted so that spring-shaped members can pass through an inspection detector, and the surface properties of the spring-shaped member can be evaluated and a pass/fail judgment made by a surface property inspection device based on output signals output from an AC bridge circuit while the spring-shaped member passes through the inspection detector.

Methods of detecting carburization, nitriding or chromium depletion in a non- or weakly ferromagnetic test object using a permanent magnet having a magnet pull force equal to or greater than about 75N and measuring either the adhesive force to detach the magnet from the test object or the attractive force in which the magnet is being pulled towards the surface of the test object.

Methods of detecting carburization, nitriding or chromium depletion in a non- or weakly ferromagnetic test object using a permanent magnet having a magnet pull force equal to or greater than about 75N and measuring either the adhesive force to detach the magnet from the test object or the attractive force in which the magnet is being pulled towards the surface of the test object.

The present invention provides a surface property inspection method including a step of setting a resistance ratio between resistors R1 and R2 of an AC bridge circuit 20 in a surface properly inspection apparatus 1. The step includes a step for placing a non-surface-treated reference test pieces S on a reference detector 22 and an inspection detector 23 and measuring a first setting output signal while changing the resistance ratio , a step for placing the reference test piece S on the reference detector 22, placing a surface-treated setting test piece on the inspection detector 23, and measuring a second setting output signal while changing the resistance ratio, a step for calculating the differential value between the first and second output signals, and a step for setting the resistance ratio so that the absolute value of the differential value is maximized.

The present invention provides a surface property inspection method including a step of setting a resistance ratio between resistors R1 and R2 of an AC bridge circuit 20 in a surface properly inspection apparatus 1. The step includes a step for placing a non-surface-treated reference test pieces S on a reference detector 22 and an inspection detector 23 and measuring a first setting output signal while changing the resistance ratio , a step for placing the reference test piece S on the reference detector 22, placing a surface-treated setting test piece on the inspection detector 23, and measuring a second setting output signal while changing the resistance ratio, a step for calculating the differential value between the first and second output signals, and a step for setting the resistance ratio so that the absolute value of the differential value is maximized.

A metal detector for buried and abandoned chemical weapons is provided, comprising: a transmitting circuit to transmit a detection signal; a frequency selection unit electrically connected to the transmitting circuit and configured to regulate a frequency of the detection signal; a receiving circuit to receive a reflected signal returned from the substance detected; an analog-digital conversion unit electrically connected to the receiving circuit and configured to convert the reflected signal into a digital signal; and a control unit electrically connected to the analog-digital conversion unit. In the present disclosure, the frequency of the detection signal can be regulated by changing a current frequency of the transmitting circuit, so that several forms of iron compound can be detected, thereby increasing the detection accuracy of the ACWs.

A metal detector for buried and abandoned chemical weapons is provided, comprising: a transmitting circuit to transmit a detection signal; a frequency selection unit electrically connected to the transmitting circuit and configured to regulate a frequency of the detection signal; a receiving circuit to receive a reflected signal returned from the substance detected; an analog-digital conversion unit electrically connected to the receiving circuit and configured to convert the reflected signal into a digital signal; and a control unit electrically connected to the analog-digital conversion unit. In the present disclosure, the frequency of the detection signal can be regulated by changing a current frequency of the transmitting circuit, so that several forms of iron compound can be detected, thereby increasing the detection accuracy of the ACWs.