EP3356083B1 - Luminescent substrate containing abrasive particles, and method for the production thereof - Google Patents

Description

FIELD OF THE INVENTION

The present invention relates to a substrate, for example a wire, containing abrasive particles, as defined in the preamble of claim 1.

The field of use of the present invention relates in particular to the sawing and polishing of materials such as silicon, sapphire or silicon carbide.

PRIOR STATE OF THE TECHNIQUE

In general, the abrasive devices are manufactured by placing abrasive particles on a substrate by means of a binder. Such an abrasive device is for example known from the document WO 02/074492 A2 .

This technique makes it possible to obtain sawing or polishing devices, for example polishing mats, cutting or polishing wheels, or cutting wires.

The binder makes it possible to bond the abrasive particles and the substrate. It is usually made of resin or metal.

However, the absence of contrast and relief between the particles and the substrate complicates any accurate monitoring of wear of the abrasive devices.

The present invention solves this problem by integrating a luminescent compound into an abrasive device.

SUMMARY OF THE INVENTION

The Applicant has developed an abrasive device incorporating at least one luminescent compound to facilitate control of its surface condition.

Thus, it is possible to control the state of the abrasive device after its manufacture, but also during its use, and therefore to replace it at the appropriate time.

• un substrat ;
• un liant C1 recouvrant au moins une partie du substrat ;
• des particules abrasives présentant un enrobage, au moins partiel, C2 ;
• un revêtement C3 recouvrant au moins en partie le liant C1 et les particules abrasives enrobées de C2 ;
• au moins un composé luminescent.

More specifically, the present invention relates to an abrasive sawing or polishing substrate, comprising:

• a substrate;
• a binder C1 covering at least a portion of the substrate;
• abrasive particles having a coating, at least partially, C2;
• a coating C3 at least partly covering the binder C1 and the coated abrasive particles of C2;
• at least one luminescent compound.

In this abrasive substrate, the coated abrasive particles of C2 are in contact with the binder C1 and with the coating C3.

In addition and advantageously, the binder C1 completely covers the substrate, the coating C2 completely covers the abrasive particles, the coating C3 completely covers the binder C1 and the abrasive particles. These properties obviously relate to a new abrasive substrate, before any use.

The substrate may especially be chosen from the group comprising: a steel wire; a textile; and a metal plate. It may be a saw wire, a polishing cloth, or a grinder disk for example.

Advantageously, the substrate is a wire comprising a steel core and having a circular cross section, advantageously a steel wire whose diameter is between 60 micrometers and 1.5 millimeters.

Those skilled in the art will be able to adapt the diameter of the core of the steel wire according to the material to be cut. Thus, a core whose diameter is between 200 micrometers and 1 millimeter is particularly suitable for cutting silicon bricks into ingots. On the other hand, a core whose diameter is between 70 and 200 microns is particularly suitable for cutting silicon wafers (better known as wafers in bricks). The core of the wire is generally in the form of a wire whose tensile strength is advantageously greater than 2000 or 3000 MPa, but generally less than 5000 MPa.

On the other hand, the core may have an elongation at break, that is to say the increase in the length of the core before it breaks, advantageously greater than 1%, even more advantageously greater than 2%. However, it remains preferentially less than 10 or 5%.

Advantageously, the core of the wire is an electrically conductive material, that is to say a material whose resistivity is less than 10 ^-5 ohm.m at 20 ° C, and in particular steel.

The steel core may especially be of a material selected from the group consisting of carbon steel, ferritic stainless steel, austenitic stainless steel, and brass steel. Carbon steel preferably contains between 0.6 and 0.8% by weight of this element.

The binder C1 makes it possible to bond the abrasive particles and the substrate.

The binder C1 is preferably metallic. It may especially consist of a layer of nickel and / or cobalt, for example a nickel / cobalt alloy whose cobalt content is between 20% and 85% by weight relative to the weight of the Ni / Co alloy. advantageously between 37 and 65%.

"Layer" means a film covering the substrate, of homogeneous composition.

Advantageously, the coating C3 is also metallic. It may especially consist of a layer of nickel and / or cobalt, for example a nickel / cobalt alloy whose cobalt content is between 10 and 90% by weight relative to the weight of the Ni / Co alloy, advantageously between 20% and 85%, more preferably between 37 and 65%.

However, the binder C1 and the coating C3 advantageously consist of metals or alloys of metals, for example Ni / Co, different from each other.

Thus, the binder C1, in contact with the substrate, may have a hardness greater than that of the coating C3, to ensure the maintenance of the abrasive particles on the substrate.

The C3 coating is generally very resistant to abrasion, but also ductile to prevent cracking. This problem of cracking can be encountered when the substrate is a wire, and more precisely during the mechanical stressing of this wire. For this, it is preferable that the coating layer C3 has sufficient ductility. In this respect, it can be seen whether the ductility of the outer layer is sufficient, by subjecting the wire to a simple tensile test until it breaks.

According to a particular embodiment, the binder C1 and the coating C3 are made of a nickel / cobalt alloy, whose cobalt content is between 20% and 85% by weight relative to the weight of the Ni / Co alloy ( independently from C1 to C3). In this case, the coating C3 is advantageously a Ni / Co alloy containing more cobalt than the binder C1. Thus, the C3 coating exhibits superior abrasion resistance properties with respect to the high percentage of cobalt. In addition, the C3 coating has higher hardness properties than the C1 binder alloy because of its adapted composition, the C3 layer being harder than the C1 layer because of a higher percentage of cobalt.

According to another particular embodiment, the hardness of the binder C1 or the coating C3, in particular of Ni / Co alloy, can be improved by introducing sulfur. This can in particular be carried out according to the method described hereinafter, by introducing sodium saccharinate (C ₇ H ₄ NO ₃ S, Na ₂ H ₂ O) in an electrolyte bath making it possible to form the binder layer C1. or C3 coating.

Thus, the binder C1 and / or the coating C3, for example of Ni / Co alloy, may contain from 100 to 1000 ppm (parts per million) by weight of sulfur, preferably from 300 to 700 ppm.

It is preferable that only C1 binder contains sulfur. Indeed, the addition of sulfur increases the hardness of the binder, but it reduces the ductility. A high sulfur content of the coating C3 can cause cracking thereof particularly when the substrate is a wire which is stretched in the cutting zone. This cracking passes water, and it electrolytically contacts the substrate with the binder. It follows a corrosion of the substrate which becomes progressively unusable.

The binder C1 and the coating C3 can in particular be obtained by successive electrolytic deposition of metals, and more particularly of metal alloys of Ni / Co type.

The metal layers constituting the binder C1 and the coating C3 advantageously have a hardness of between 300 and 800 Hv, advantageously between 300 and 500 Hv.

The hardness of a layer of metal or metal alloy (C1 and C3) is measured using a micro-durometer according to the techniques forming part of the general knowledge of those skilled in the art. A Vickers indenter is generally used, with a load compatible with the thickness of the layer. This charge is generally between 1 gram-force and 100 gram-strength. If the impression left by the Vickers indenter is too big compared to the thickness of the layer (even with a low load), we can use a Knoop indenter (narrower), and convert the Knoop hardness value. in Vickers hardness, using a conversion table.

As already indicated, the abrasive particles are coated with a layer of C2. This coating C2 is advantageously metallic, more preferably a material selected from the group comprising nickel, cobalt, iron, copper, and titanium.

On the other hand, the abrasive particles are advantageously made of a material chosen from the group comprising silicon carbide SiC; silica SiO ₂ ; tungsten carbide WC; silicon nitride Si ₃ N ₄ ; cubic boron nitride cBN; CrO ₂ chromium dioxide; Al ₂ O ₃ aluminum oxide; Diamonds ; and diamonds pre-coated with nickel, iron, cobalt, copper, or titanium, or their alloys.

According to a particular embodiment, the abrasive substrate may comprise several types of distinct abrasive particles.

Those skilled in the art will be able to choose the appropriate combination binding C1 / abrasive particles depending on the use of the abrasive substrate, for example depending on the material to be cut when the abrasive substrate is an abrasive wire.

The abrasive particles consist of grains coated with a coating C2, which may be distinct from the binder C1 and the coating C3. This coating C2 at least partially covers each grain, advantageously completely. The materials covering the grains, such as grains of diamonds, are, for example, nickel, cobalt, iron, copper, or titanium.

The total diameter of the particles, that is to say the grain and the coating C2, is advantageously between 1 micrometer and 500 micrometers. When the substrate is a steel wire, the diameter of the particles is preferably less than one third of the diameter of the core of the steel wire. Thus, according to a particular embodiment, the diameter of the particles may be between 10 and 22 microns for a wire whose core has a diameter of 0.12 mm.

Diameter means the largest diameter (or the largest dimension) of the particles when they are not spherical.

Advantageously, the coating C2 covering the grain is made of a ferromagnetic material at the manufacturing temperature of the abrasive wire (electrolytic deposition of the abrasive particles - see the method described below). Nickel, iron, and cobalt are examples. These metals can be alloyed with each other, and they can also contain hardening elements such as sulfur and phosphorus. It should be noted that phosphorus decreases the ferromagnetism of nickel, and that, in this case, it is necessary to limit its concentration.

In addition, the material forming the coating C2 is advantageously electrically conductive.

The coating C2 at least partially covers the abrasive particles, advantageously completely. However, during the use of the abrasive substrate according to the invention, the portion of the grain in contact with the material to be cut or polished is devoid of coating, the latter being eroded at the first cutting operations, the same way that the coating C3.

The mass of the coating C2, relative to the total mass of the coated particles, is advantageously between 10% and 60%, especially in the case of diamond grains.

This coating C2 may in particular be deposited on the grains prior to the use of grains / abrasive particles in the method of manufacturing the abrasive substrate according to the invention. The techniques that can be implemented for the deposition of a coating C2 on each of the grains include sputtering, but also electrolysis, chemical vapor deposition (CVD). Vapor Deposition "), and electrochemical electroless plating (Electroless Nickel Plating).

In general, 5 to 50% of the surface of the abrasive substrate is occupied by abrasive particles, themselves possibly being covered by the coating C3 when the wire is new.

As already indicated, the abrasive substrate according to the invention comprises at least one luminescent compound. This compound is advantageously in the form of luminescent particles, advantageously inorganic luminescent particles, and still more advantageously inorganic fluorescent particles.

The inorganic luminescent particles may advantageously be chosen from the group comprising the particles based on, and advantageously constituted by, metal oxide; metallic sesquioxide; metal oxyfluoride; vanadate metal; of metal fluoride, and mixtures thereof.

It may especially be inorganic particles selected from the group comprising Y ₂ O ₃ ; YVO ₄ ; Gd ₂ O ₃ ; Gd ₂ O ₂ S; LaF ₃ ; and their mixtures.

The particles are advantageously doped with one or more active centers of the family of lanthanides or of the family of transition elements.

In addition, the luminescent particles can be used in mixtures to create a luminescent optical code.

Advantageously, the luminescent particles are doped with ions of the family of lanthanides, advantageously europium. The intensity of the luminescence depends on the doping rate and can go through a maximum. Thus, the doping of these particles may vary from 0.5 to 50% relative to the number of moles of metal constituting the particles, more preferably from 1 to 5%.

Several markers, ie several types of luminescent particles can be used to mark the substrate. In this case, the amount of each type of incorporated particles may be different. In addition, each type of particle can have its own signature. In other words, the authentication of the substrate may require the detection of several particles at different wavelengths.

Thus, by varying the proportion of each of the different markers, several optical codes can be created with respect to the relative intensity of the luminescence signals.

According to a particular embodiment, the particles may comprise within the same particle different optical signatures detectable at different wavelengths. It is then diptych or triptych particles for example.

In general, the particles may have a spherical, cubic, cylindrical, parallelepipedic shape.

The size of the particles is defined by their largest average size, that is to say by their diameter when they are spherical, their average length when they are rod-shaped.

Thus, in the context of the invention, the luminescent particles are particles whose average size is advantageously between 4 and 1000 nanometers.

According to a preferred embodiment, the particles are nanoparticles.

The average size of the nanoparticles is advantageously between 4 and 100 nanometers, more preferably between 20 and 50 nanometers.

In addition, the particles, and more advantageously the nanoparticles, can be encapsulated (coated), in particular in a polysiloxane or silicon oxide matrix. The new polysiloxane or silica surface can then be functionalized with organosilane coupling agents, such as substituted alkoxysilanes such as aminopropyltriethoxysilane or derivatives of the same family. The formation of the polysiloxane surface or the functionalization of this surface makes it possible to improve the dispersion in the solvent and the stability of the particles in the dispersions. Moreover, these surface modifications of the particles can affect the hydrophilic / hydrophobic character of the particles and thus modify the affinity and diffusivity of the inorganic luminescent particles within the binder C1, the coating C2 or the coating C3. A better homogeneity of the distribution of the luminescent particles can thus be obtained.

When the particles are coated, their average size also remains within the size ranges mentioned above. In general, the coating increases the average particle size of the order of 5 to 15 nanometers.

• un composé luminescent CL1 dans le liant C1 ;
• un composé luminescent CL2 dans l'enrobage C2 ;
• un composé luminescent CL3 dans le revêtement C3 ;
• deux composés luminescents CL1 et CL2 respectivement dans le liant C1 et dans l'enrobage C2 ; CL1 et CL2 étant distincts l'un de l'autre ;
• deux composés luminescents CL1 et CL3 respectivement dans le liant C1 et dans le revêtement C3 ; CL1 et CL3 étant distincts l'un de l'autre ;
• deux composés luminescents CL2 et CL3 respectivement dans l'enrobage C2 et dans le revêtement C3 ; CL2 et CL3 étant distincts l'un de l'autre ;
• trois composés luminescents CL1, CL2 et CL3 respectivement dans le liant C1, l'enrobage C2, et le revêtement C3 ; CL1, CL2 et CL3 étant distincts les uns des autres.

The abrasive substrate according to the invention may comprise one or more luminescent compounds. Thus, according to seven particular embodiments, the abrasive substrate may comprise one of the following combinations:

• a luminescent compound CL1 in the binder C1;
• a luminescent compound CL2 in the coating C2;
• a luminescent compound CL3 in the coating C3;
• two luminescent compounds CL1 and CL2 respectively in the binder C1 and in the coating C2; CL1 and CL2 being distinct from each other;
• two luminescent compounds CL1 and CL3 respectively in the binder C1 and in the coating C3; CL1 and CL3 being distinct from each other;
• two luminescent compounds CL2 and CL3 respectively in the coating C2 and in the coating C3; CL2 and CL3 being distinct from each other;
• three luminescent compounds CL1, CL2 and CL3 respectively in the binder C1, the coating C2, and the coating C3; CL1, CL2 and CL3 being distinct from each other.

• formation d'un substrat abrasif par dépôt électrolytique sur un substrat d'un liant C1 et de particules abrasives éventuellement magnétiques, par passage dans un bain B₁ d'électrolyte contenant des particules abrasives,
  • ▪ lesdites particules abrasives présentant un enrobage, au moins partiel, C2,
  • ▪ le liant C1 recouvrant au moins partiellement le substrat, avantageusement intégralement ;
• dépôt électrolytique d'un revêtement C3, par passage dans un bain B₂ d'électrolyte,
  • ▪ le revêtement C3 recouvrant au moins partiellement le liant C1 et les particules abrasives, avantageusement intégralement,
  • ▪ les particules abrasives étant en contact avec le liant C1 et le revêtement C3 ;
• intégration d'au moins un composé luminescent dans au moins une couche parmi le liant C1, l'enrobage C2 ou le revêtement C3.

The present invention also relates to a method for preparing the abrasive substrate according to the invention. This process comprises the following steps:

• forming an abrasive substrate by electrolytic deposition on a substrate of a binder C1 and possibly magnetic abrasive particles, by passing through an electrolyte bath B ₁ containing abrasive particles,
  • Said abrasive particles having a coating, at least partially, C2,
  • ▪ the binder C1 at least partially covering the substrate, advantageously integrally;
• electrolytic deposition of a C3 coating, by passing through an electrolyte bath B ₂ ,
  • The coating C3 at least partially covering the binder C1 and the abrasive particles, advantageously completely,
  • The abrasive particles being in contact with the binder C1 and the coating C3;
• integrating at least one luminescent compound into at least one of C1 binder, C2 coating or C3 coating.

In this method, at least one luminescent compound is integrated with the abrasive substrate. As already indicated, it can be integrated in the binder C1 and / or in the coating C2 and / or in the coating C3.

According to a particular embodiment, a luminescent compound CL1 can be introduced into the bath B1 so as to be incorporated in the binder C1.

According to another particular embodiment, a luminescent compound CL2 may be introduced beforehand into the coating C2.

According to another particular embodiment, a luminescent compound CL3 can be introduced into the bath B2 so as to be incorporated in the coating C3.

In general, the luminescent compound is introduced in the form of an aqueous solution of nanoparticles or luminescent nanocolloids in a homogeneous aqueous solution (bath B ₁ and / or bath B ₂ ). The resulting aqueous solution is then subjected to the application of a known method of electrolytic (or galvanic) deposition on a substrate.

When the luminescent compound is incorporated in the binder C1 or the coating C3, its amount may represent 0.05 to 5% by weight relative to the weight of the binder C1 or the coating C3, advantageously 0.1 to 1%.

In order to ensure this doping, the luminescent compound may have a concentration of between 0.01 and 5 g / 100 in the bath B ₁ or B ₂ , advantageously 0.5 to 1 g / 100.

When the luminescent compound is integrated in the coating C2, its amount may represent 0.05 to 5% by weight relative to the weight of the coating C2, advantageously 0.1 to 1%.

The luminescent compound CL2 is integrated in C2 by means of an electrolyte bath in which the abrasive particles coated with a metal layer advantageously deposited by CVD are immersed.

Advantageously, the electrolyte baths B ₁ and B ₂ comprise metal ions forming the binder C1 and the coating C2. They may in particular comprise at least cobalt ions and / or nickel ions.

In practice, Co ²⁺ and Ni ²⁺ ions are generally introduced into the baths B ₁ and B ₂ . However, other oxidation levels can coexist, but, in general, they are very minor in concentration in the electrolysis baths.

• dégraissage du substrat en milieu alcalin ;
• décapage du substrat en milieu acide.

Advantageously, the process may also comprise at least one of the following steps, before the electrolytic deposition:

• degreasing of the substrate in an alkaline medium;
• stripping of the substrate in acidic medium.

The bath B ₂ may have a composition of metal ions, such as nickel and cobalt ions, distinct from that of the bath B ₁ . The bath B ₂ is advantageously devoid of abrasive particles.

According to a particular embodiment, the coating C3 may be pure cobalt metal that resists abrasion.

According to a particular embodiment, the coating C3 may be covered by one or more layers. The layer or layers covering the coating C3 may be obtained either by reiteration of the passage in the bath B ₂ , or by passage through at least one other electrolytic bath comprising ions Co II and Ni II.

Advantageously, the baths B ₁ and B ₂ , and if appropriate the other baths, comprise, independently of one another, between 1 and 150 g / l of cobalt II ions and between 50 and 150 g / l of nickel ions II.

On the other hand, the bath B ₁ comprises between 1 and 100 g / l of abrasive particles.

As already indicated, the hardness of the binder C1 or the coating C3 can also be improved by incorporation of sulfur.

Thus, the sulfur can be introduced in particular by addition of sodium saccharinate (C ₇ H ₄ NO ₃ S, Na ₂ H ₂ O) in the electrolyte bath B ₁ or B ₂ , advantageously only in B ₁ . The quantity introduced may be between 1 and 10 g / l, advantageously of the order of 5 g / l.

During the formation of the binder C1 or the coating C3, the temperature of the bath B ₁ or B ₂ is advantageously between 60 and 90 ° C.

For more details on the steps of the process as well as the device used, the skilled person can call upon his technical knowledge and particularly the content of the document FR 2 988 628 .

Once the abrasive substrate has been formed, it can be subjected to a lapping step which makes it possible to improve the performance of the abrasive substrate at the output of manufacture by discovering the abrasive particles.

The invention also relates to the use of the abrasive substrate described above, for sawing or polishing a material that can be chosen especially from the group comprising silicon, sapphire, and silicon carbide. The abrasive substrate can be used in the production of wafers of silicon.

Those skilled in the art will know how to adapt the abrasive substrate according to the material to be cut or polished. More particularly, the abrasive particles are chosen to be harder than the material to be cut or polished.

The invention and the advantages thereof will appear more clearly from the following figures and examples given to illustrate the invention and not in a limiting manner.

DESCRIPTION OF THE FIGURES

• The figure 1 illustrates a conventional abrasive wire.
• The figure 2 illustrates a coated abrasive particle.
• The figure 3 illustrates a first device for detecting the luminescence of the abrasive wire according to the invention.
• The figure 4 illustrates a second device for detecting the luminescence of the abrasive wire according to the invention.
• The figure 5 illustrates the luminescence of an abrasive wire according to a particular embodiment of the invention.
• The figure 6 illustrates the luminescence of an abrasive wire according to a particular embodiment of the invention.
• The figure 7 illustrates the luminescence of an abrasive wire according to a particular embodiment of the invention.
• The figure 8 corresponds to the emission spectra of a plate treated with a galvanic deposition solution containing fluorescent particles.

DETAILED DESCRIPTION OF THE INVENTION

The present invention provides important advantages in the regular control of the abrasive properties of the abrasive substrate according to the invention.

• un substrat (1) ;
• un liant C1 recouvrant le substrat (1) ;
• des particules abrasives (2) présentant un enrobage C2 ;
• un revêtement C3 recouvrant le liant C1 et les particules abrasives (2) enrobées de C2.

The figure 1 represents a substrate (1) comprising sawing or polishing abrasive, comprising:

• a substrate (1);
• a binder C1 covering the substrate (1);
• abrasive particles (2) having a C2 coating;
• a coating C3 covering the binder C1 and the abrasive particles (2) coated with C2.

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

In the present invention, the abrasive substrate comprises at least one luminescent compound CL in the binder C1 and / or in the coating C2 and / or in the coating C3.

Thus, in order to obtain different information on the abrasive substrate, it is possible to dissociate the fluorescence signal on the three layers C1, C2 and C3.

As illustrated by Figures 3 and 4 the presence of the luminescent compound CL can be detected by different devices. The quality control and wear control of the abrasive substrate can be monitored by these devices that can excite the luminescent compounds, coupled with the acquisition of images. Thus, it is possible to check the number of diamonds after manufacture or when using the abrasive substrate.

The system of acquisition / observation of luminescence according to the figure 3 comprises a camera C and a lens O provided with a bandpass filter for selecting the emission wavelength of the luminescent compound integrated in the abrasive substrate.

The emission of the luminescent compound can be ensured by exposing the abrasive substrate SA to a filtered light source SL.

The luminescence acquisition system according to the figure 4 comprises an optical fiber spectrometer S, the illumination (excitation of the luminescent compound) being carried out by a laser La with a chosen wavelength and a spectrum width sufficiently fine to avoid any spurious signal.

When the abrasive substrate SA comprises a plurality of luminescent compounds, one or more excitation sources may be used to detect all the luminescent compounds present in the abrasive substrate SA. In this case, an image acquisition system comprising one or more optical filters may be used, the filters only allowing the desired wavelengths for measuring the quality or wear of the abrasive substrate.

The quantification of the detected signal is ensured by a calibration of the system with wear standards of the abrasive substrate so as to define two main thresholds, high and low threshold.

On the other hand, it is preferable to clean the abrasive substrate prior to measuring its luminescence. This cleaning eliminates any unwanted signals from dirt cutting or polishing. It can be made by high-pressure water jet just before the acquisition zone which itself is outside the cutting or polishing zone.

• en sortie de la machine de fabrication, en stoppant le défilement pendant le temps d'acquisition pour suivre la qualité du substrat abrasif ; ou
• dans la zone de découpe ou de polissage pour suivre l'usure du substrat abrasif. Pour un fil abrasif, il peut s'agir de la chambre de bobinage et dé-bobinage d'une machine de découpe industrielle à fils (par exemple pour les tranches (wafers) solaires), la mesure de luminescence pouvant se produire à chaque changement de sens du fil lors de la coupe.

Thus, the measurement of the luminescence of the abrasive substrate can be carried out from a device, for example according to the figure 3 or 4 , installed:

• at the output of the manufacturing machine, stopping the scrolling during the acquisition time to monitor the quality of the abrasive substrate; or
• in the cutting or polishing zone to follow the wear of the abrasive substrate. For an abrasive wire, it may be the winding chamber and de-winding of an industrial wire cutting machine (for example for wafers), the luminescence measurement can occur at each change of the direction of the thread when cutting.

The figure 5 corresponds to a particular embodiment of the invention in which the abrasive substrate comprises a luminescent compound CL1 in the binder C1.

In general, the abrasive substrate is replaced as soon as the signal L1 reaches a predefined threshold corresponding to a wear rate that does not allow it to perform its sawing or polishing function. A calibration of the control device makes it possible to define this threshold.

This configuration makes it possible to monitor the wear of the abrasive substrate by monitoring the appearance of the signal L1 corresponding to the emission of the luminescent compound CL1. This signal appears as soon as abrasive particles (2) are torn from the substrate (1).

This embodiment (CL1 in C1) is particularly suitable for a diamond grinding wheel type substrate which requires regular brightening to discover the abrasive particles so as to maintain its abrasive power. The presence of a luminescent compound in the binder C1 makes it possible to indicate the end of life of the tool.

The figure 6 corresponds to a particular embodiment of the invention in which the abrasive substrate comprises a luminescent compound CL2 in the coating C2.

In use, wear of the abrasive substrate can be monitored by monitoring the decrease of the L2 signal. However, the small amount of the layer C2 and thus CL2 around the particles has the disadvantage of limiting the dynamics of the measurement.

This embodiment is particularly suitable for a textile substrate. For example, in a polishing mat, the presence of a luminescent compound in the coating C2 makes it possible to control the abrasive quality of the carpet. A sharp decrease in the signal emitted by the luminescent compound then corresponds to a decrease in the abrasive properties resulting from the loss of abrasive particles. It is then necessary to replace the carpet.

The figure 7 corresponds to a particular embodiment of the invention in which the abrasive substrate comprises a luminescent compound CL3 in the coating C3.

In this configuration, the presence of the luminescent compound CL3 in the coating C3 makes it possible to create a contrast between CL3 and the abrasive particles C2.

The luminescence signal comes from the coating C3. No signal is observed at the level of the diamonds when they have been ground, that is to say without the C3 coating. This configuration makes it possible to follow the wear of the wire thanks to a predefined low signal threshold commanding the stopping of the machine as soon as this threshold is reached.

The abrasive substrate according to the invention can also comprise simultaneously two or three luminescent compounds among CL1 (in C1), CL2 (in C2) and CL3 (in C3).

This embodiment makes it possible to improve the monitoring of the quality and wear of the abrasive substrate from its manufacture until its change.

This embodiment is particularly suitable for substrates of the diamond polishing support type. In this case, the binder C1 and / or the coating C2 of the abrasive particles may respectively comprise the luminescent compounds CL1 and CL2. The emission of CL1 and / or the absence or decrease of the emission of CL2 demonstrates the reduction of the abrasive power, triggering the replacement of the abrasive substrate.

EXAMPLES OF CARRYING OUT THE INVENTION

1. a) Formation d'un liant C1 comprenant des particules abrasives et un composé luminescent CL1 (INV-1).

The following examples illustrate the formation, on a metal substrate, of a) a binder C1 comprising a luminescent compound CL1, b) a coating C3 comprising a luminescent compound CL3.

1. a) Formation of a binder C1 comprising abrasive particles and a luminescent compound CL1 (INV-1).

• préparation d'une première solution contenant 500ml d'eau dé-ionisée, 600g/l de sel de nickel (sulfate de nickel) et 5 à 60g/l de particules abrasives ;
• préparation d'une deuxième solution aqueuse de 200ml de solution de nanocolloïdes cationiques (YVO₄:Eu) à 4g/l ;
• formation d'un bain électrolyte par mélange de la première et de la deuxième solutions ;
• ajustement à pH = 2 par addition d'acide sulfamique.

A solution containing abrasive particles, a luminescent compound and metal ions was prepared as follows:

• preparation of a first solution containing 500 ml of deionized water, 600 g / l of nickel salt (nickel sulphate) and 5 to 60 g / l of abrasive particles;
• preparation of a second aqueous solution of 200 ml of cationic nanocolloid solution (YVO ₄ : Eu) at ₄ g / l;
• forming an electrolyte bath by mixing the first and second solutions;
• adjustment to pH = 2 by addition of sulfamic acid.

Once the first and second solutions are mixed, the galvanic treatment is carried out on a brass substrate at a temperature of 50 ° C.

The galvanic deposition is carried out with mechanical stirring of the electrolyte bath so as to maintain the dispersion of the particles in solution.

Electrolytic deposition is accomplished by passing a current between two electrodes in the aqueous electrolyte bath. The substrate to be covered corresponds to one of the electrodes (cathode). The skilled person will use his knowledge to determine the nature (intensity, potential) of the current to be applied, depending on the geometry, the distance between electrodes, the nature of the metal ions or their concentration in solution ( see in particular: Galvanotechnical Treaty, Louis Lacourcelle, 1997, Galva-Conseils Edition ).

The current flow conditions, the reaction time and the geometry of the electrodes in the bath are interdependent and are fixed so as to obtain a layer 4 microns thick covering the surface of the cathode at the end of the deposition time ( 1 minute).

These conditions make it possible to obtain a homogeneous deposition of binder C1 comprising abrasive particles and a luminescent compound CL1.
b) Formation of a coating C3 comprising a luminescent compound CL3 (INV-2, figure 8 ).

The protocol described for the binder C1 was followed, but in the absence of abrasive particles in the first solution containing the nickel salt.

The solution thus prepared is homogeneous. It is not a dispersion requiring permanent agitation. In addition, the cationic nanocolloid solution used has a migration behavior towards the cathode similar to that of the metal ions used in the solution to form a metal deposit under the influence of a galvanic current.

These conditions make it possible to obtain a homogeneous deposition of coating C2 comprising a luminescent compound CL2.
(c) Counterexample (EC, figure 8 ).

• mélanger une dispersion de poudres de composés luminescents de dispersité sub-micrométrique et micrométrique ;
• maintenir la dispersion en solution par voie d'agitation ; et
• procéder au dépôt galvanique sur un substrat en laiton.

This counterexample consists in:

• mixing a dispersion of powders of luminescent compounds of sub-micrometric and micrometric dispersity;
• maintain dispersion in solution by agitation; and
• proceed with the galvanic deposition on a brass substrate.

The resulting substrate has fluorescent zones but distributed very heterogeneously.

It emerges from Examples a) to c) the importance of preparing the electrolyte bath by mixing between the luminescent compounds in the form of an aqueous solution and a solution containing the metal salts precursors of the metal deposit.

The solution of luminescent compounds does not interfere with the migration of ions and nanoparticles in homogeneous solution under the effect of the current. It is possible to form a smooth metal surface. On the other hand, the presence of particles in suspension disturbs the deposition of the metal layer, rendering it rough, heterogeneous and discontinuous.

The third curve of the figure 8 optimizes the excitation of the luminescent compound for better efficiency.

Claims (10)

1. An abrasive sawing or polishing substrate, comprising:

   - a substrate (1) ;

   - a binder C1 covering at least a portion of the substrate;

   - abrasive particles (2) having an at least partial coating, C2;

   - a coating C3 coating binder C1 and the abrasive particles coated with C2; the abrasive particles coated with C2 being in contact with binder C1 and with coating C3;

   in which the abrasive substrate is characterized by at least one light-emitting compound.
2. The abrasive substrate of claim 1, characterized in that:

   - the substrate is selected from the group comprising: a steel wire; a textile; and a metal plate;

   - 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;

   - coating C2 of the abrasive particles is made of a material selected from the group comprising nickel; cobalt; iron; copper; and titanium;

   - 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.
3. The abrasive substrate of claim 1 or 2, characterized in that it comprises a light-emitting compound CL1 in binder C1.
4. The abrasive substrate of any of claims 1 to 3, characterized in that it comprises a light-emitting compound CL2 in coating C2.
5. The abrasive substrate of any of claims 1 to 4, characterized in that it comprises a light-emitting compound CL3 in coating C3.
6. The abrasive substrate of any of claims 1 to 5, characterized in that 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.
7. The abrasive substrate of any of claims 1 to 6, characterized in that the abrasive particles are made of a material selected from the group comprising silicon carbide SiC; silica SiO₂; tungsten carbide WC; silicon nitride Si₃N₄; cubic boron nitride cBN; chromium dioxide CrO₂; aluminum oxide Al₂O₃; diamond; and diamonds pre-coated with nickel, iron, cobalt, copper, or titanium, or with alloys thereof.
8. The abrasive substrate of any of claims 1 to 7, characterized in that the light-emitting compound is selected from the group comprising metal oxide; metal sesquioxide; metal oxyfluoride; metal vanadate; metal fluoride; and mixtures thereof.
9. A method of manufacturing the abrasive substrate (1) of any of claims 1 to 8, comprising the steps of:

   - forming of an abrasive substrate by electrodeposition on a substrate of a binder C1 and of abrasive particles (2), by passing through an electrolyte bath B₁ 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 B₂,

   ▪ coating C3 at least partially covering binder C1 and the abrasive particles,

   ▪ the abrasive particles being in contact with binder C1 and coating C3;

   the method of manufacturing being characterized by the integration of at least one light-emitting compound in at least one layer from among binder C1, coating C2, or coating C3.
10. A method of manufacturing the abrasive substrate of claim 9, characterized in that the light-emitting compound is introduced in the form of an aqueous solution of light-emitting nanoparticles or nanocolloids into bath B₁ or B₂.

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