Luminescent substrate containing abrasive particles, and method for the production thereof

Abstract

An abrasive sawing or polishing substrate includes a substrate, a binder C1 covering at least a portion of the substrate, and abrasive particles having an at least partial coating, C2. The abrasive sawing or polishing substrate also includes a coating C3 coating binder C1 and the abrasive particles coated with C2 and at least one light-emitting compound. The abrasive particles coated with C2 are in contact with binder C1 and with coating C3.

Claims

1. An abrasive sawing or polishing substrate, comprising: a substrate; a binder C1 covering at least a portion of the substrate; abrasive particles having an at least partial coating, C2; a coating C3 coating binder C1 and the abrasive particles coated with C2; at least one light-emitting compound; the abrasive particles coated with C2 being in contact with binder C1 and with coating C3, and wherein the substrate is selected from the group comprising: a steel wire; a textile; and a metal plate; wherein binder C1 is made of at least one layer of a nickel/cobalt alloy having a cobalt content in the range from 20% to 85% by weight with respect to the weight of the Ni/Co alloy; wherein coating C2 of the abrasive particles is made of a material selected from the group comprising nickel; cobalt; iron; copper; and titanium; and wherein coating C3 is made of at least one layer of a nickel/cobalt alloy having a cobalt content in the range from 10% to 90% by weight with respect to the weight of the Ni/Co alloy.

2. An abrasive sawing or polishing substrate, comprising: a substrate; a binder C1 covering at least a portion of the substrate; abrasive particles having an at least partial coating, C2; a coating C3 coating binder C1 and the abrasive particles coated with C2; at least one light-emitting compound: the abrasive particles coated with C2 being in contact with binder C1 and with coating C3, wherein said substrate comprises a light-emitting compound CL1 in binder C1.

3. An abrasive sawing or polishing substrate, comprising: a substrate; a binder C1 covering at least a portion of the substrate; abrasive particles having an at least partial coating, C2; a coating C3 coating binder C1 and the abrasive particles coated with C2; at least one light-emitting compound: the abrasive particles coated with C2 being in contact with binder C1 and with coating C3, wherein said substrate comprises a light-emitting compound CL2 in coating C2.

4. An abrasive sawing or polishing substrate, comprising: a substrate; a binder C1 covering at least a portion of the substrate; abrasive particles having an at least partial coating, C2; a coating C3 coating binder C1 and the abrasive particles coated with C2; at least one light-emitting compound: the abrasive particles coated with C2 being in contact with binder C1 and with coating C3, wherein said substrate comprises a light-emitting compound CL3 in coating C3.

5. The abrasive substrate of claim 1, wherein the substrate comprises: a light-emitting compound CL1 in binder C1; a light-emitting compound CL2 in coating C2; a light-emitting compound CL3 in coating C3; CL1, CL2, and CL3 being different from one another.

6. The abrasive substrate of claim 1, wherein the abrasive particles are made of a material selected from the group comprising silicon carbide SiC; silica SiO.sub.2; tungsten carbide WC; silicon nitride Si.sub.3N.sub.4; cubic boron nitride cBN; chromium dioxide CrO.sub.2; aluminum oxide Al.sub.2O.sub.3; diamond; and diamonds pre-coated with nickel, iron, cobalt, copper, or titanium, or with alloys thereof.

7. The abrasive substrate of claim 1, wherein the light-emitting compound is selected from the group comprising metal oxide; metal sesquioxide; metal oxyfluoride; metal vanadate; metal fluoride; and mixtures thereof.

8. A method of manufacturing an abrasive sawing or polishing substrate having (i) a substrate, (ii) a binder C1 covering at least a portion of the substrate, (iii) abrasive particles having at least a partial coating, C2, (iv) a coating C3 coating binder C1 and the abrasive particles coated with C2, and (v) at least one light-emitting compound, wherein the abrasive particles coated with C2 are in contact with binder C1 and with coating C3, the method comprising the steps of: forming of an abrasive substrate by electrodeposition on a substrate of a binder C1 and of abrasive particles, by passing through an electrolyte bath B.sub.1 containing abrasive particles, said abrasive particles having an at least partial coating, C2, binder C1 at least partially covering the substrate; electrodeposition of a coating C3, by passing through an electrolyte bath B.sub.2, coating C3 at least partially covering binder C1 and the abrasive particles, the abrasive particles being in contact with binder C1 and coating C3; integration of at least one light-emitting compound in at least one layer from among binder C1, coating C2, or coating C3, wherein the substrate is selected from the group comprising: a steel wire; a textile; and a metal plate; wherein binder C1 is made of at least one layer of a nickel/cobalt alloy having a cobalt content in the range from 20% to 85% by weight with respect to the weight of the Ni/Co alloy; wherein coating C2 of the abrasive particles is made of a material selected from the group comprising nickel; cobalt; iron; copper; and titanium; and wherein coating C3 is made of at least one layer of a nickel/cobalt alloy having a cobalt content in the range from 10% to 90% by weight with respect to the weight of the Ni/Co alloy.

9. The method of manufacturing the abrasive substrate of claim 8, wherein the light-emitting compound is introduced in the form of an aqueous solution of light-emitting nanoparticles or nanocolloids into bath B.sub.1 or B.sub.2.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 illustrates a conventional abrasive wire.

(2) FIG. 2 illustrates a coated abrasive particle.

(3) FIG. 3 illustrates a first device enabling to detect the luminescence of the abrasive wire.

(4) FIG. 4 illustrates a second device enabling to detect the luminescence of the abrasive wire.

(5) FIG. 5 illustrates the luminescence of the abrasive wire according to a specific embodiment.

(6) FIG. 6 illustrates the luminescence of an abrasive wire according to a specific embodiment.

(7) FIG. 7 illustrates the luminescence of an abrasive wire according to a specific embodiment.

(8) FIG. 8 corresponds to the emission spectra of a wafer treated with a galvanic deposition solution containing fluorescent particles.

DETAILED DESCRIPTION

(9) The presently described embodiments provide significant advantages in the regular control of the abrasive properties of the abrasive substrate.

(10) FIG. 1 shows a substrate (1) comprising a sawing or polishing abrasive, comprising:

(11) a substrate (1);

(12) a binder C1 covering the substrate (1);

(13) abrasive particles (2) having a coating C2;

(14) a coating C3 coating binder C1 and the abrasive particles (2) coated with C2.

(15) The abrasive particles (2) coated with C2 (FIG. 2) are in contact with binder C1 and with coating C3.

(16) In embodiments, the abrasive substrate may comprise at least one light-emitting compound CL in binder C1 and/or in coating C2 and/or in coating C3.

(17) Thus, to obtain different data relative to the abrasive substrate, the fluorescence signal may be dissociated on the three layers C1, C2, and C3.

(18) As illustrated in FIGS. 3 and 4, the presence of light-emitting compound CL may be detected due to different devices. The quality control and the wear monitoring of the abrasive substrate may be followed-up by means of these devices which can excite the light-emitting compounds, coupled to the acquisition of images. It is thus possible to verify the number of diamonds at the end of the manufacturing or on use of the abrasive substrate.

(19) The system of acquisition/observation of the luminescence according to FIG. 3 comprises a camera C and a lens O provided with a bandpass filter to select the emission wavelength of the light-emitting compound integrated to the abrasive substrate.

(20) The emission of the light-emitting compound may be ensured by exposure of the abrasive substrate SA to a filtered light source SL.

(21) The luminescence acquisition system of FIG. 4 comprises an optical fiber spectrometer S, the illumination (excitation of the light-emitting compound) being performed by a laser La with a selected wavelength and a sufficiently fine spectrum width to avoid any parasitic signal.

(22) When abrasive substrate SA comprises a plurality of light-emitting compounds, one or a plurality of excitation sources may be used to detect all the light-emitting compounds present in abrasive substrate SA. In this case, an image acquisition system comprising one or a plurality of optical filters may be used, the filters only letting through the desired wavelengths for the abrasive substrate quality or wear measurement.

(23) The quantification of the detected signal is ensured by a calibration of the system with wear gauges for the abrasive substrate to define two main thresholds, a high and a low threshold.

(24) On the other hand, it is preferably to clean the abrasive substrate prior to measuring its luminescence. Such a cleaning enables to do away with possible parasitic signals due to cutting or polishing dust. It may be performed by high pressure water jet just before the acquisition area, which is itself located outside of the cutting or polishing area.

(25) Thus, the measurement of the luminescence of the abrasive substrate may be performed from a device, for example, according to FIG. 3 or 4, installed:

(26) at the output of the manufacturing machine, by stopping the advancement during the acquisition time to monitor the quality of the abrasive substrate; or

(27) in the cutting or polishing area to monitor the wearing of the abrasive substrate. For an abrasive wire, it may be the winding and unwinding chamber of an industrial wire cutting machine (for example, for solar wafers), where the luminescence measurement may occur each time the wire direction changes during the cutting.

(28) FIG. 5 corresponds to a specific embodiment in which the abrasive substrate comprises a light-emitting compound CL1 in binder C1.

(29) Generally, the abrasive substrate is replaced as soon as signal L1 reaches a predefined threshold corresponding to a wear rate which does not enable it to carry out its sawing of polishing function. A calibration of the control device enables to define this threshold.

(30) Such a configuration enables to monitor the wearing of the abrasive substrate by monitoring the occurrence of signal L1 corresponding to the emission of light-emitting compound CL1. This signal appears as soon as abrasive particles (2) are torn from the substrate (1).

(31) This embodiment (CL1 in C1) is particularly adapted to a substrate of diamond grinding wheel type which requires a regular dressing to expose the abrasive particles in order to keep its abrasive power. The presence of a light-emitting compound in binder C1 enables to indicate the end of the tool lifetime.

(32) FIG. 6 corresponds to a specific embodiment in which the abrasive substrate comprises a light-emitting compound CL2 in coating C2.

(33) During its use, the wearing of the abrasive substrate may be monitored by supervising the decrease of signal L2. However, the small quantity of layer C2 and thus of CL2 around the particles has the disadvantage of limiting the dynamic range of the measurement.

(34) This embodiment is particularly adapted to a textile substrate. For example, in a polishing pad, the presence of a light-emitting compound in coating C2 enables to control the abrasive quality of the pad. A strong decrease in the signal emitted by the light-emitting compound then corresponds to a decrease in the abrasive properties resulting from the loss of abrasive particles. It is then necessary to replace the pad.

(35) FIG. 7 corresponds to a specific embodiment in which the abrasive substrate comprises a light-emitting compound CL3 in coating C3.

(36) In this configuration, the presence of light-emitting compound CL3 in coating C3 enables to create a contrast between CL3 and abrasive particles C2.

(37) The luminescence signal originates from coating C3. No signal can be observed at the level of the diamonds when they have been lapped, that is, deprived of coating C3. Such a configuration enables to monitor the wearing of the wire due to a predefined low signal threshold controlling the stopping of the machine as soon as the threshold has been reached.

(38) The abrasive substrate may also simultaneously comprise two or three light-emitting compounds from among CL1 (in C1), CL2 (in C2), and CL3 (in C3).

(39) This embodiment enables to improve the monitoring of the quality and of the wearing of the abrasive substrate from its manufacturing to its change.

(40) This embodiment is particularly adapted to substrates of diamond polishing support type. In this case, binder C1 and/or coating C2 of the abrasive particles may respectively comprise light-emitting compounds CL1 and CL2. The emission of CL1 and/or the absence or decrease of the emission of CL2 show(s) the decrease of the abrasive power, triggering the replacement of the abrasive substrate.

ILLUSTRATIVE EMBODIMENTS

(41) The following examples illustrate the forming, on a metal substrate, a) of a binder C1 comprising a light-emitting compound CL1, b) of a coating C3 comprising a light-emitting compound CL3.

(42) a) Forming of a binder C1 comprising abrasive particles and a light-emitting compound CL1 (INV-1).

(43) A solution containing abrasive particles, a light-emitting compound, and metal ions has been prepared as follows:

(44) preparation of a first solution containing 500 ml of deionized water, 600 g/l of nickel salt (nickel sulfate), and from 5 to 60 g/l of abrasive particles;

(45) preparation of a second aqueous solution of 200 ml of a solution of cationic nanocolloids (YVO.sub.4:Eu) at 4 g/l;

(46) forming of an electrolyte bath by mixture of the first and of the second solutions;

(47) adjustment to pH=2 by addition of sulfamic acid.

(48) Once the first and second solutions have been mixed, the galvanic treatment is performed on a brass substrate, at a 50 C. temperature.

(49) The galvanic deposition is performed under mechanical stirring of the electrolyte bath to maintain the particle dispersed in the solution.

(50) The electrodeposition is performed by flowing of a current between two electrodes in the aqueous electrolytic bath. The substrate to be covered corresponds to one of the electrodes (cathode). It will be within the abilities of those skilled in the art to determine the nature (intensity, potential) of the current to be applied, according to the geometry, to the distance between electrodes, to the nature of the metal ions, or to their concentration in the solution (see, in particular: Trait de Galvanotechnique, Louis Lacourcelle, 1997, Galva-Conseils Edition).

(51) The current flow conditions, the reaction time, and the geometry of the electrodes in the bath are interdependent and are determined to obtain a layer having a 4-micrometer width covering the cathode surface at the end of the deposition time (1 minute).

(52) Such conditions enable to obtain a homogeneous deposition of binder C1 comprising abrasive particles and a light-emitting compound CL1.

(53) b) Forming of a coating C3 comprising a light-emitting compound CL3 (INV-2, FIG. 8).

(54) The protocol described for binder C1 has been followed, this time in the absence of abrasive particles in the first solution containing the nickel salt.

(55) The solution thus prepared is homogeneous. It is not a dispersion requiring a permanent stirring. Further, the solution of cationic nanocolloids used has a behavior of migration to the cathode similar to that of the metal ions used in the solution to form a metal deposition under the influence of a galvanic current.

(56) Such conditions enable to obtain a homogeneous deposition of coating C2 comprising a light-emitting compound CL2.

(57) c) Counter-example (CE, FIG. 8)

(58) This counter-example comprises:

(59) mixing a dispersion of powders of light-emitting compounds having a submicrometer- and micrometer-range dispersity;

(60) maintaining the dispersion in solution by stirring; and

(61) performing the galvanic deposition on a brass substrate.

(62) The resulting substrate exhibits fluorescent areas, however very heterogeneously distributed.

(63) Examples a) to c) show the importance of preparing the electrolyte bath by mixture between the light-emitting components in the form of an aqueous solution and a solution containing the precursor metal salts for the metal deposition.

(64) The solution of light-emitting compounds does not disturb the migration of the ions and of the nanoparticles in homogeneous solution under the effect of current. It is possible to form a smooth metal surface. However, the presence of particles in suspension disturbs the deposition of the metal layer, making it rough, heterogeneous, and discontinuous.

(65) The third curve of FIG. 8 enables to optimize the excitation of the light-emitting compound for a better efficiency.