Ceramic abrasive material capable of being used for steel rail grinding as well as preparation method and application of ceramic abrasive material

Abstract

The invention discloses a ceramic abrasive material composition, a ceramic abrasive material prepared from the ceramic abrasive material composition and a ceramic abrasive material abrasive belt comprising the ceramic abrasive material. The ceramic abrasive composition comprises the following components in parts by weight: 15-45 parts of aluminum oxide, 10-25 parts of cubic silicon carbide, 1-4 parts of silicon dioxide, 5-10 parts of a sintering additive, 1-4 parts of iron oxide, 1-5 parts of a wetting agent, 3-6 parts of vanadium pentoxide, 1-4 parts of zirconium oxide and 5-20 parts of water, wherein the cubic silicon carbide is alpha-silicon carbide, the purity of the cubic silicon carbide is 95% or above, and the Mohs hardness of the cubic silicon carbide is 9.0 or above. The invention also discloses a preparation method of the cubic silicon carbide. The ceramic abrasive material disclosed by the invention has excellent grinding performance and is suitable for grinding steel rails.

Description

Technical Field

[0001] The invention belongs to the field of grinding and grinding devices, and particularly relates to a ceramic abrasive that can be used for rail grinding, a preparation method thereof, and an application thereof. Background Art

[0002] Rails, as the most crucial component of rail transit systems like railways and subways, are directly related to train safety and are a key focus of track maintenance, repair, and safety risk prevention. After prolonged use by trains, rails can develop surface damage such as surface defects, abrasions, dents, corrugations, side wear, and fish scales. Failure to promptly polish damaged rails can lead to train jolting and even accidents.

[0003] Currently, the main grinding tools used for rail grinding are grinding wheels and abrasive belts. Unlike the rigid grinding of grinding wheels, belt grinding is a flexible contact grinding method. The contact length of abrasive belts with the workpiece within the grinding zone is greater than that of grinding wheels, resulting in a greater number of abrasive grains involved in grinding. The load on each abrasive grain is small and uniform, resulting in less grain breakage. Therefore, the wear of the entire abrasive belt is much less than that of a grinding wheel. Furthermore, the abrasive grains of abrasive belts are sharper than those of grinding wheels, providing better cutting conditions, minimal material deformation during grinding, and a high removal rate.

[0004] Sanding belts are coated abrasives, and their basic components are: a substrate, abrasive, and a binder, with the abrasive bonded to the substrate via the binder. Abrasives are classified by hardness into two main categories: superhard abrasives and conventional abrasives. To adapt to the hardness of rails, sanding belts used for rail grinding often use superhard abrasives such as corundum, diamond, and cubic boron nitride. For example, the abrasive disclosed in publication number CN101664904A is diamond / cubic boron nitride, while publication number CN108908146A discloses black corundum abrasives. Publication number CN112876950A discloses abrasive particles comprising one or more of natural corundum, garnet jade, white corundum, brown corundum, silicon carbide, zirconium corundum, artificial diamond, and cubic boron nitride. Another example is the abrasive disclosed in publication number CN112876950A using single crystal corundum. The abrasive is either directly embedded on the adhesive to form an abrasive layer, or is encapsulated with resin or alloy powder and then solidified or brazed to form an abrasive layer, which is then adhered to the substrate.

[0005] Due to the special operating mode of railway transportation and rail transit, the maintenance window of rails is relatively short. Therefore, it is necessary to continue to improve the formulation of superhard abrasives to provide ceramic abrasives suitable for rail grinding with low cost, excellent grinding performance and wide ambient temperature adaptability. Summary of the Invention

[0006] The present application provides a new ceramic abrasive composition that can be used for rail grinding, a ceramic abrasive prepared from the composition, and an abrasive belt for rail grinding comprising the ceramic abrasive.

[0007] One object of the present application is to provide a ceramic abrasive composition comprising the following components in parts by weight:

[0008] 15-45 parts of aluminum oxide, 10-25 parts of cubic silicon carbide, 1-4 parts of silicon dioxide, 5-10 parts of sintering additive, 1-4 parts of iron oxide, 1-5 parts of wetting agent, 3-6 parts of vanadium pentoxide, 1-4 parts of zirconium oxide and 5-20 parts of water;

[0009] Wherein, the cubic silicon carbide is prepared by the following method:

[0010] I. mixing quartz powder and graphite powder in a mass ratio of 1:0.5 to 1, and then performing a first sintering at about 1500° C. to about 2000° C. for about 10 to about 12 hours to obtain a first sintered mixture;

[0011] II. The first sintered mixture obtained in step I is crushed, mixed, and then subjected to a second sintering at about 3000 ℃ to about 3200 ℃ for a sintering time of about 10 to about 12h to obtain a second sintered mixture;

[0012] III. The second sintered mixture obtained in step II is sieved, and the silicon carbide particles on the sieve are taken;

[0013] IV. The silicon carbide particles obtained in step III are washed, dried, crushed and sieved in sequence to obtain cubic silicon carbide with a particle size of 20 to 50 nm.

[0014] Preferably, the mass ratio of quartz powder to graphite powder is 1:0.6-0.9.

[0015] Also preferably, the particle size of the quartz powder is 230-450 μm.

[0016] Preferably, the particle size of the graphite powder is 200-350 μm.

[0017] Preferably, the mixing in step I and the mixing in step II are each independently carried out by mechanical stirring at a rotation speed of about 400 to about 500 r / min, more preferably about 400 to about 450 r / min, and a stirring time of about 8 to about 12 h, more preferably about 10 to about 12 h.

[0018] Preferably, in step I, the first sintering temperature is about 1600° C. to about 1800° C., and the sintering time is about 12 hours.

[0019] Preferably, in the step II, the first sintered mixture is crushed to a particle size of 50 to 100 μm.

[0020] Preferably, in step II, the second sintering temperature is about 3000° C. to about 3100° C., and the sintering time is 12 hours.

[0021] In step IV, the drying conditions are not limited, and can be natural drying or heat drying.

[0022] In step IV, mechanical or manual screening can be used, for example, using a vibrating screening machine for screening.

[0023] Quartz powder as a silicon source and graphite powder as a carbon source undergo a solid-phase carbothermal reduction reaction at high temperature to produce large-sized cubic silicon carbide particles (mostly α-silicon carbide). The cubic silicon carbide particles can be separated from the unreacted powdered quartz powder and graphite powder by simple sieving.

[0024] Preferably, in step IV, the washing solvent is water.

[0025] The water can be tap water or purified water, such as deionized water, distilled water, etc.

[0026] In order to improve washing efficiency and reduce costs, high-pressure tap water washing can be used.

[0027] In step IV, the pulverization method may be a commonly used method in the art, including but not limited to grinding, ball milling, etc.

[0028] Preferably, in step IV, the particle size of the cubic boron carbide particles obtained by screening is 30 to 40 nm.

[0029] The cubic silicon carbide prepared by the above method is α-silicon carbide with a purity of more than 95% and a Mohs hardness of more than 9.0.

[0030] As a preferred embodiment, the present application provides a ceramic abrasive composition comprising the following components in parts by weight:

[0031] 15-45 parts of aluminum oxide, 15-25 parts of cubic silicon carbide, 1-2 parts of silicon dioxide, 6-9 parts of sintering additives, 1-2 parts of iron oxide, 2-5 parts of wetting agent, 3-5 parts of vanadium pentoxide, 1-3 parts of zirconium oxide and 5-15 parts of water.

[0032] As a more preferred embodiment, the present application provides a ceramic abrasive composition comprising the following components in parts by weight:

[0033] 20-40 parts of aluminum oxide, 15-20 parts of cubic silicon carbide, 1.5-2 parts of silicon dioxide, 5-8 parts of sintering additives, 1.5-2 parts of iron oxide, 3-4 parts of wetting agent, 3-4 parts of vanadium pentoxide, 2-3 parts of zirconium oxide and 10-15 parts of water.

[0034] In the above preferred embodiments, the cubic silicon carbide is prepared by the method described in the present application, and has a particle size of 20 to 50 nm, preferably 30 to 40 nm.

[0035] Preferably, the aluminum oxide is α-aluminum oxide.

[0036] Also preferably, the particle size of the α-alumina is 50 to 200 nm, more preferably 50 to 100 nm.

[0037] Preferably, the sintering additive is selected from one of magnesium oxide and calcium oxide, or the two in any proportion.

[0038] Preferably, the wetting agent is selected from one of dextrin and sodium carboxymethyl cellulose or the two in any ratio.

[0039] Another object of the present application is to provide a method for preparing a ceramic abrasive, using the above-mentioned ceramic abrasive composition as a raw material, comprising the following steps:

[0040] S1. The components are mixed in parts by weight and pressed to obtain a green body;

[0041] S2. The green body obtained in step S1 is first pre-fired in stages at about 40°C to about 100°C for a total of about 10 to 24 hours, and then continuously roasted in stages at about 800°C to about 1500°C for a total of about 60 to 240 minutes; the roasted product is immediately water quenched, then ball-milled and dried, and sieved according to particle size to obtain ceramic abrasives of different particle size ranges.

[0042] Preferably, in step S1, during the pressing process, the pressure is about 100-150 MPa, and the pressure is maintained for about 30-60 minutes.

[0043] Preferably, in step S2, the continuous staged pre-burning is performed, and the heating program is:

[0044] First, raise the temperature from room temperature to about 40°C, keep warm for about 2 to 3 hours, then raise the temperature by about 10°C each time, keep warm for about 2 to 3 hours, until the temperature is raised to about 100°C, keep warm for about 2 to 3 hours.

[0045] Specifically, the temperature rising procedure of continuous staged pre-firing is: room temperature → about 40°C, keep warm for about 2 to 3 hours; about 40°C → about 50°C, keep warm for about 2 to 3 hours; about 50°C → about 60°C, keep warm for about 2 to 3 hours; about 60°C → about 70°C, keep warm for about 2 to 3 hours; about 70°C → about 80°C, keep warm for about 2 to 3 hours; about 80°C → about 90°C, keep warm for about 2 to 3 hours; about 90°C → about 100°C, keep warm for about 2 to 3 hours.

[0046] The moisture in the green body can be fully removed through the above-mentioned staged pre-firing.

[0047] Preferably, in step S2, the continuous staged roasting is three-stage roasting; the process conditions of each stage roasting are:

[0048] First calcination, temperature is about 800℃ to about 900℃, and calcination time is about 20 to about 30 minutes;

[0049] The second calcination temperature is about 1000°C to about 1200°C, and the calcination time is about 30 to about 120 minutes;

[0050] The third calcination is performed at a temperature of about 1300° C. to about 1500° C. and a calcination time of about 30 to about 60 minutes.

[0051] Preferably, the first calcination is performed at a temperature of about 800° C. to 850° C. and for a time of about 30 minutes.

[0052] Preferably, the second calcination is performed at a temperature of about 1100° C. to 1200° C., and for a time of about 60 to about 120 minutes.

[0053] Preferably, the third calcination is performed at a temperature of about 1400° C. to 1450° C. and for about 60 minutes.

[0054] Also preferably, the heating rate to the first calcination temperature is about 5 to 10° C. / min, more preferably about 5 to 8° C. / min.

[0055] Preferably, the heating rate to the second calcination temperature is about 10-20° C. / min, more preferably about 15-20° C. / min.

[0056] Preferably, the heating rate to the third calcination temperature is about 10-20° C. / min, more preferably about 15-20° C. / min.

[0057] The green body is sintered through the above procedure, and the components react fully, the grains become finer and more uniform, and the grinding performance of the abrasive is improved.

[0058] In step S2, the green body after calcination is rapidly placed in water for water quenching. The water quenching operation can be carried out according to conventional operations in the art. Water quenching can quickly reduce the temperature of the calcined product, fix the crystal structure in the calcined product, improve the physical properties of the ceramic abrasive, and increase the hardness of the ceramic abrasive.

[0059] Preferably, in step S2, the drying is oven drying at a temperature of about 80°C to about 120°C, more preferably about 100°C.

[0060] In step S2, the dried abrasive is sieved according to particle size to obtain abrasives of different particle size specifications.

[0061] In addition, another object of the present application is to provide a ceramic abrasive prepared by the above preparation method.

[0062] The present application also provides a ceramic abrasive sanding belt, wherein a binder layer, an abrasive layer and a resin layer are sequentially arranged on a base, and the abrasive layer is formed by the ceramic abrasive described in the present application.

[0063] Preferably, the abrasive layer has a thickness of about 0.1 to 0.3 mm.

[0064] Those skilled in the art should understand that the thickness of the abrasive layer refers to the height of the portion of the abrasive exposed from the adhesive layer.

[0065] The adhesive layer and the resin layer are each independently formed of bismaleimide resin glue or phenolic modified epoxy resin.

[0066] The substrate can be any synthetic fiber material that can be used as a sanding belt substrate, for example, it can be pure polyester grey cloth, nylon, polyester cloth base, etc., preferably pure polyester grey cloth.

[0067] The sand belt can be prepared by gravity sand planting or electrostatic sand planting methods conventional in the art.

[0068] The present application also provides a method for preparing the above-mentioned ceramic abrasive belt, comprising the following operations:

[0069] One side of the substrate is fully coated with bismaleimide resin glue or phenolic modified epoxy resin; then the ceramic abrasive described in this application is evenly covered on the entire surface of the adhesive layer by gravity sand planting or electrostatic sand planting to form an abrasive layer about 0.1 to 0.3 mm thick; finally, a layer of bismaleimide resin glue or phenolic modified epoxy resin is coated on the surface of the abrasive layer to obtain.

[0070] The present application also provides the use of the ceramic abrasive belt described in the present application in rail grinding.

[0071] According to tests, the ceramic abrasive provided herein has excellent compressive strength, which gives the ceramic abrasive belt described in this application good grinding performance.

[0072] In the specification of this application, the numerical value of "parts by weight" indicates the mass ratio between the relevant components, rather than the actual mass. Depending on the actual situation, 1 part by weight can be any mass, such as 1g, 10g, 50g, 100g, 450g, 500g, 1kg, etc.

[0073] In the description of the present application, the term "about" has the meaning that a person of ordinary skill in the art would reasonably give it when used in conjunction with a specified numerical value or range, namely, indicating slightly above or slightly below the specified value or range: within the range of ±10% of the specified value, ±9% of the specified value, ±8% of the specified value, ±7% of the specified value, ±6% of the specified value, ±5% of the specified value, ±4% of the specified value, ±3% of the specified value, ±2% of the specified value, or ±1% of the specified value. DETAILED DESCRIPTION

[0074] The present invention is described below with reference to specific examples. Those skilled in the art will appreciate that these examples are only used to illustrate the present invention and are not intended to limit the scope of the present invention in any way.

[0075] The experimental methods in the following examples are conventional methods unless otherwise specified. The raw materials, reagents, etc. used in the following examples are commercially available products unless otherwise specified.

[0076] Quartz powder: particle size is 230-450μm;

[0077] Graphite powder: particle size is 200-350μm;

[0078] α-alumina: particle size is 50-100nm.

[0079] Example 1 A ceramic abrasive composition and ceramic abrasive prepared therefrom

[0080] The ceramic abrasive composition of this embodiment is composed of the following components: 20 parts by weight of α-aluminum oxide, 20 parts by weight of cubic silicon carbide (particle size of 30-40 nm), 2 parts by weight of silicon dioxide, 5 parts by weight of magnesium oxide (sintering additive), 2 parts by weight of iron oxide, 3 parts by weight of dextrin (wetting agent), 3 parts by weight of vanadium pentoxide, 2 parts by weight of zirconium oxide, and 10 parts by weight of water; where 1 part by weight = 1 kg.

[0081] The cubic silicon carbide is prepared by the following method:

[0082] I. adding quartz powder and graphite powder in a mass ratio of 1:0.6 into a device equipped with a stirring device, stirring at 450 rpm for about 10 hours, performing a first sintering at about 1600°C for about 12 hours to obtain a first sintered mixture, and cooling to room temperature;

[0083] II. The first sintered mixture was crushed to a particle size of 50 to 70 μm and then transferred to a device with a stirring device, stirred at 450 r / min for about 10 h, and a second sintering was performed at about 3000 ° C for about 12 h,

[0084] obtaining a second sintered mixture, and cooling the mixture to room temperature;

[0085] III using a vibrating screening machine to sieve the second sintered mixture, discard the powder, take the silicon carbide particles on the sieve;

[0086] IV. The silicon carbide particles were rinsed with high-pressure tap water, dried at about 100°C, crushed, and sieved to obtain cubic silicon carbide with a particle size of 30 to 40 nm.

[0087] The ceramic abrasive composition is used as a raw material to prepare the ceramic abrasive by the following method:

[0088] S1. Take the ceramic abrasive composition, mix well, then place in a mold, and press at a pressure of about 120 MPa for about 30 min to obtain a green body;

[0089] S2. The green body obtained in step S1 is placed in an oven, heated from room temperature to about 40°C, and kept warm for 2 hours; then heated to about 50°C, and kept warm for about 2 hours; then heated to about 60°C, and kept warm for about 2 hours; then heated to about 70°C, and kept warm for about 3 hours; then heated to about 80°C, and kept warm for about 3 hours; then heated to about 90°C, and kept warm for about 3 hours; finally heated to about 100°C, and kept warm for about 3 hours; then placed in a tube furnace, heated to about 800°C at 5°C / min and kept warm for about 30 minutes for the first roasting, then heated to about 1100°C at 15°C / min and kept warm for about 120 minutes for the second roasting; finally heated to about 1400°C at 15°C / min and kept warm for about 60 minutes for the third roasting, and then immediately water quenched; after being taken out of water, ball milled, then dried at about 100°C, sieved according to particle size, and obtained ceramic abrasives of different particle size specifications.

[0090] Example 2 A ceramic abrasive composition and ceramic abrasive prepared therefrom

[0091] The ceramic abrasive composition of this embodiment is composed of the following components, by weight: 30 parts by weight of α-aluminum oxide, 20 parts by weight of cubic silicon carbide (particle size of 30-40 nm), 2 parts by weight of silicon dioxide, 6 parts by weight of magnesium oxide (sintering additive), 2 parts by weight of iron oxide, and dextrin (wetting agent).

[0092] 3 parts by weight, 3 parts by weight of vanadium pentoxide, 2 parts by weight of zirconium oxide and 10 parts by weight of water. 1 part by weight = 1 kg.

[0093] The cubic silicon carbide is prepared by the following method:

[0094] I. adding quartz powder and graphite powder in a mass ratio of 1:0.7 to a device equipped with a stirring device, stirring at 400 rpm for about 12 hours, and performing a first sintering at about 1800° C. for about 10 hours to obtain a first sintered mixture;

[0095] II. The first sintered mixture was crushed to a particle size of 80 to 100 μm, transferred to an apparatus with a stirring device, stirred at 400 r / min for about 12 h, and sintered for a second time at about 3200 ° C for about 10 h to obtain a second sintered mixture;

[0096] III using a vibrating screening machine to sieve the second sintered mixture, discard the powder, take the silicon carbide particles on the sieve;

[0097] IV. The silicon carbide particles were rinsed with high-pressure tap water, dried naturally, crushed, and sieved to obtain cubic silicon carbide with a particle size of 30 to 40 nm.

[0098] The ceramic abrasive composition is used as a raw material to prepare the ceramic abrasive by the following method:

[0099] S1. Taking the ceramic abrasive composition, mixing it uniformly, placing it in a mold, and pressing it at a pressure of about 150 MPa for about 30 minutes to obtain a green body;

[0100] S2. The green body obtained in step S1 is placed in an oven, heated from room temperature to about 40°C, and kept warm for about 3 hours; then heated to about 50°C, and kept warm for about 3 hours; then heated to about 60°C, and kept warm for about 3 hours; then heated to about 70°C, and kept warm for about 3 hours; then heated to about 80°C, and kept warm for about 3 hours; then heated to about 90°C, and kept warm for about 3 hours; finally heated to about 100°C, and kept warm for about 3 hours; then placed in a tube furnace, heated to about 900°C at 10°C / min and kept warm for about 20 minutes for the first roasting, then heated to about 1200°C at 20°C / min and kept warm for about 90 minutes for the second roasting; finally heated to about 1450°C at 20°C / min and kept warm for about 30 minutes for the third roasting, and then immediately water quenched; after being taken out of water, ball milled, then dried at about 100°C, sieved according to particle size, and obtained ceramic abrasives of different particle size specifications.

[0101] Example 3 A ceramic abrasive composition and ceramic abrasive prepared therefrom

[0102] The ceramic abrasive composition of this embodiment is composed of the following components, by weight: 40 parts α-aluminum oxide, 15 parts cubic silicon carbide (particle size 30-40 nm), 2 parts silicon dioxide, 8 parts magnesium oxide (sintering additive), 2 parts iron oxide, 3 parts dextrin (wetting agent), 3 parts vanadium pentoxide, 2 parts zirconium oxide, and 15 parts water. Where 1 part by weight = 1 kg.

[0103] The cubic silicon carbide is prepared by the following method:

[0104] I. adding quartz powder and graphite powder in a mass ratio of 1:1 into a device equipped with a stirring device, stirring at 500 rpm for about 8 hours, performing a first sintering at about 1500°C for about 12 hours to obtain a first sintered mixture, and cooling to room temperature;

[0105] II. The first sintered mixture was crushed to a particle size of 60 to 80 μm, transferred to an apparatus with a stirring device, stirred at 500 r / min for about 10 h, and sintered for a second time at about 3100 ° C for about 12 h to obtain a second sintered mixture, which was cooled to room temperature;

[0106] III using a vibrating screening machine to sieve the second sintered mixture, discard the powder, take the silicon carbide particles on the sieve;

[0107] IV. The silicon carbide particles were washed with high-pressure tap water, dried naturally, crushed, and sieved to obtain cubic silicon carbide with a particle size of 30 to 40 nm.

[0108] The ceramic abrasive composition is used as a raw material to prepare the ceramic abrasive by the following method:

[0109] S1. Take the ceramic abrasive composition, mix well, then place in a mold, and press at a pressure of about 100 MPa for about 30 min to obtain a green body;

[0110] S2. The green body obtained in step S1 is placed in an oven, heated from room temperature to about 40°C, and kept warm for about 2 hours; then heated to about 50°C, and kept warm for about 2 hours; then heated to about 60°C, and kept warm for about 2 hours; then heated to about 70°C, and kept warm for about 2 hours; then heated to about 80°C, and kept warm for about 3 hours; then heated to about 90°C, and kept warm for about 3 hours; finally heated to about 100°C, and kept warm for about 3 hours; then placed in a tube furnace, heated to about 850°C at 8°C / min and kept warm for 30 minutes for the first roasting, then heated to about 1200°C at 20°C / min and kept warm for about 90 minutes for the second roasting; finally heated to about 1300°C at 20°C / min and kept warm for about 60 minutes for the third roasting, and then immediately water quenched; after being taken out of water, ball milled, then dried at about 100°C, sieved according to particle size, and obtained ceramic abrasives of different particle size specifications.

[0111] Examples 4 to 6: A ceramic abrasive belt

[0112] The ceramic abrasive belts of Examples 4 to 6 include a substrate and a binder layer, an abrasive layer, and a resin layer sequentially disposed on the substrate; wherein the substrate is a pure polyester fabric, the binder layer and the resin layer are formed of bismaleimide resin glue, and the abrasive layers are ceramic abrasives prepared in Examples 1 to 3, respectively, with a particle size of P400 (the abrasive layer of Example 4 is formed of the ceramic abrasive of Example 1, the abrasive layer of Example 5 is formed of the ceramic abrasive of Example 2, and the abrasive layer of Example 6 is formed of the ceramic abrasive of Example 3); and are prepared by the following steps:

[0113] Bismaleimide resin glue is fully coated on one side of the all-polyester grey cloth, and a binder layer is formed after the surface is dried; then, the ceramic abrasives with a particle size of P400 prepared in Examples 1 to 3 are respectively taken and fed into the electrostatic area of ​​the electrostatic sand planting machine, so that the ceramic abrasives are evenly attached to the binder layer to form a 0.1 mm thick abrasive layer. After drying, a layer of bismaleimide resin glue is coated on the surface of the abrasive layer to form a resin layer, and a ceramic abrasive belt is obtained after drying.

[0114] Comparative Example 1 A ceramic abrasive composition and ceramic abrasive prepared therefrom

[0115] The ceramic abrasive composition of this embodiment is composed of the following components: 20 parts by weight of α-aluminum oxide, 55 parts by weight of cubic silicon carbide (particle size of 30-40 nm), 2 parts by weight of silicon dioxide, 5 parts by weight of magnesium oxide (sintering additive), 2 parts by weight of iron oxide, 3 parts by weight of dextrin (wetting agent), 3 parts by weight of vanadium pentoxide, 2 parts by weight of zirconium oxide, and 10 parts by weight of water; where 1 part by weight = 1 kg.

[0116] The preparation process of cubic silicon carbide and the preparation process of ceramic abrasive are the same as those in Example 1.

[0117] Comparative Example 2 A ceramic abrasive composition and ceramic abrasive prepared therefrom

[0118] The difference from Example 1 is that there is no silicon dioxide in the ceramic abrasive composition; the preparation process of cubic silicon carbide and the preparation process of the ceramic abrasive are the same as those in Example 1.

[0119] Comparative Example 3 A ceramic abrasive composition and ceramic abrasive prepared therefrom

[0120] The ceramic abrasive composition of this embodiment is composed of the following components: 20 parts by weight of α-aluminum oxide, 20 parts by weight of cubic silicon carbide (particle size of 30-40 nm), 2 parts by weight of silicon dioxide, 5 parts by weight of magnesium oxide (sintering additive), 2 parts by weight of iron oxide, 3 parts by weight of dextrin (wetting agent), 3 parts by weight of vanadium pentoxide, 2 parts by weight of zirconium oxide, and 10 parts by weight of water; where 1 part by weight = 1 kg.

[0121] The cubic silicon carbide is prepared by the following method:

[0122] I. Quartz powder and graphite powder were added to a device equipped with a stirring device in a mass ratio of 1:5, stirred at 450 r / min for 10 hours, and sintered at 1200°C for 12 hours to obtain a first sintered mixture, which was then cooled to room temperature;

[0123] II. The first sintered mixture was crushed to a particle size of 50 to 80 μm, transferred to an apparatus with a stirring device, stirred at 450 r / min for 10 h, and sintered for a second time at 2500 ° C for 12 h to obtain a second sintered mixture, which was cooled to room temperature;

[0124] III using a vibrating screening machine to sieve the second sintered mixture, discard the powder, take the silicon carbide particles on the sieve;

[0125] IV. The silicon carbide particles were washed with high-pressure tap water, dried at about 100°C, crushed, and sieved to obtain cubic silicon carbide with a particle size of 30 to 40 nm.

[0126] The preparation process of the ceramic abrasive is the same as that in Example 1.

[0127] Comparative Example 4 A ceramic abrasive composition and ceramic abrasive prepared therefrom

[0128] The ceramic abrasive composition is exactly the same as that in Example 1, and the ceramic abrasive is prepared by the following method:

[0129] S1. Take the ceramic abrasive composition, mix well, then place in a mold, and press at a pressure of about 120 MPa for about 30 min to obtain a green body;

[0130] S2. The green body obtained in step S1 is placed in an oven, heated from room temperature to about 40°C, and kept warm for about 2 hours; then heated to about 50°C, and kept warm for about 2 hours; then heated to about 60°C, and kept warm for about 2 hours; then heated to about 70°C, and kept warm for about 3 hours; then heated to about 80°C, and kept warm for about 3 hours; then heated to about 90°C, and kept warm for about 3 hours; finally heated to about 100°C, and kept warm for about 3 hours; then placed in a tube furnace, heated to 800°C at 5°C / min and kept warm for about 30 minutes for the first roasting, then heated to 1400°C at 15°C / min and kept warm for 150 minutes for the second roasting; then immediately water quenched; taken out of water and ball milled, then dried at about 100°C, sieved according to particle size, and obtained ceramic abrasives of different particle size specifications.

[0131] Comparative Example 5 A ceramic abrasive composition and ceramic abrasive prepared therefrom

[0132] The ceramic abrasive composition is exactly the same as that in Example 1, and the ceramic abrasive is prepared by the following method:

[0133] S1. Take the ceramic abrasive composition, mix well, then place in a mold, and press at a pressure of about 120 MPa for about 30 min to obtain a green body;

[0134] S2. The green body obtained in step S1 is placed in an oven, heated directly from room temperature to 100°C, and kept warm for 18 hours; then placed in a tubular furnace, heated to 800°C at a rate of 5°C / min and kept warm for 30 minutes for a first calcination, then heated to 1100°C at a rate of 15°C / min and kept warm for 120 minutes for a second calcination; finally, heated to 1400°C at a rate of 15°C / min and kept warm for 60 minutes for a third calcination, and then immediately water quenched; after being removed from water, ball milled, dried at about 100°C, and sieved according to particle size to obtain ceramic abrasives of different particle size specifications.

[0135] Comparative Example 6 A ceramic abrasive composition and ceramic abrasive prepared therefrom

[0136] The ceramic abrasive composition is exactly the same as that in Example 1, and the ceramic abrasive is prepared by the following method:

[0137] S1. Take the ceramic abrasive composition, mix well, then place in a mold, and press at a pressure of about 120 MPa for about 30 min to obtain a green body;

[0138] S2. The green body obtained in step S1 is placed in an oven, heated from room temperature to about 40°C, and kept warm for 2 hours; then heated to about 50°C, and kept warm for 2 hours; then heated to about 60°C, and kept warm for 2 hours; then heated to about 70°C, and kept warm for 3 hours; then heated to about 80°C, and kept warm for 3 hours; then heated to about 90°C, and kept warm for 3 hours; finally heated to about 100°C, and kept warm for 3 hours; then placed in a tubular furnace, heated to 1400°C at a rate of 5°C / min, and kept warm for 210 minutes for roasting; then immediately water quenched; taken out of water, ball milled, and then dried at about 100°C, sieved according to particle size, and obtained ceramic abrasives of different particle size specifications.

[0139] Comparative Examples 7-12 Ceramic Abrasive Belt

[0140] The ceramic abrasive belts of Comparative Examples 7 to 12 comprise a substrate and a binder layer, an abrasive layer, and a resin layer sequentially disposed on the substrate; wherein the substrate is a pure polyester grey cloth, the binder layer and the resin layer are formed of bismaleimide resin glue, and the abrasive layer is the ceramic abrasive prepared in Comparative Examples 1 to 6, with a particle size of P400; and are prepared by the following steps:

[0141] Bismaleimide resin glue is fully coated on one side of the all-polyester grey cloth, and a binder layer is formed after the surface is dried; then the ceramic abrasives with a particle size of P400 prepared in comparative examples 1 to 6 are respectively taken and fed into the electrostatic area of ​​the electrostatic sand planting machine, so that the ceramic abrasives are evenly attached to the binder layer to form a 0.1 mm thick abrasive layer. After drying, a layer of bismaleimide resin glue is coated on the surface of the abrasive layer to form a resin layer, and a ceramic abrasive belt is obtained after drying.

[0142] Test Case

[0143] The grinding performance tests were performed on the ceramic abrasive belts of Examples 4 to 6 and Comparative Examples 7 to 12, respectively.

[0144] The test employed a belt surface grinding method. The ceramic abrasive belt to be tested was cut into a 400# circular sanding disc with a diameter of 150 mm. The disc was secured to its back with Velcro. A steel workpiece was then surface ground on a universal grinder using a water-based emulsion at a speed of 1250 rpm, a grinding time of 60 seconds, and a grinding pressure of 0.05 MPa. The measured removal rate and surface roughness Ra of the workpiece are shown in Table 1.

[0145] Table 1 Grinding performance of ceramic abrasive belts of Examples 4 to 6 and Comparative Examples 7 to 12

[0146] sanding belt Ceramic abrasives <![CDATA[Removal rate mm 3 / s]]> Surface roughness Ra / μm Example 4 Example 1 7.33 0.43 Example 5 Example 2 7.25 0.52 Example 6 Example 3 7.36 0.56 Comparative Example 7 Comparative Example 1 3.95 0.82 Comparative Example 8 Comparative Example 2 5.56 0.66 Comparative Example 9 Comparative Example 3 4.02 1.01 Comparative Example 10 Comparative Example 4 4.21 1.06 Comparative Example 11 Comparative Example 5 6.85 0.62 Comparative Example 12 Comparative Example 6 6.15 0.95

[0147] As can be seen from Table 1, the ceramic abrasive provided by the present invention has excellent grinding performance; however, from the ceramic abrasive of Comparative Example 1, the addition of cubic silicon carbide is too much and is not within the scope of this application, so the grinding performance of the sanding belt is not improved but reduced; from the ceramic abrasive of Comparative Example 2, the composition lacks silicon dioxide and iron oxide, the grinding rate of the sanding belt is significantly reduced, and the surface roughness is improved. This is because the addition of silicon dioxide and iron oxide can improve the hardness and wear resistance of the ceramic abrasive, thereby improving the grinding rate of the sanding belt. In addition, from the ceramic abrasive of Comparative Example 3, the preparation process of cubic silicon carbide is different from that of the present application, and the obtained material is not α-silicon carbide, so the ceramic abrasive prepared thereby has poor grinding performance; from the ceramic abrasives of Comparative Examples 4, 5 and 6, the roasting process affects the grinding performance of the sanding belt to a certain extent.

Claims

1. A ceramic abrasive composition comprising the following components in parts by weight: 15-45 parts of aluminum oxide, 10-25 parts of cubic silicon carbide, 1-4 parts of silicon dioxide, 5-10 parts of sintering additive, 1-4 parts of iron oxide, 1-5 parts of wetting agent, 3-6 parts of vanadium pentoxide, 1-4 parts of zirconium oxide and 5-20 parts of water; in, The cubic silicon carbide is α-silicon carbide with a purity of more than 95% and a Mohs hardness of more than 9.0, and is prepared by the following method: I. mixing quartz powder and graphite powder in a mass ratio of 1:0.5 to 1, and then performing a first sintering at about 1500° C. to about 2000° C. for about 10 to about 12 hours to obtain a first sintered mixture; II. The first sintered mixture obtained in step I is crushed, mixed, and then subjected to a second sintering at about 3000 ℃ to about 3200 ℃ for a sintering time of about 10 to about 12h to obtain a second sintered mixture; III. The second sintered mixture obtained in step II is sieved, and the silicon carbide particles on the sieve are taken; IV. The silicon carbide particles obtained in step III are washed, dried, crushed and sieved in sequence to obtain cubic silicon carbide with a particle size of 20 to 50 nm.

2. The ceramic abrasive composition according to claim 1, wherein The mass ratio of quartz powder to graphite powder is 1:0.6-0.9; Preferably, the particle size of the quartz powder is 230 to 450 μm; Preferably, the particle size of the graphite powder is 200-350 μm.

3. The ceramic abrasive composition according to claim 1, wherein The mixing in step I and the mixing in step II are each independently carried out by mechanical stirring at a speed of about 400 to about 500 r / min, more preferably about 400 to about 450 r / min, and a stirring time of about 8 to about 12 hours, more preferably about 10 to about 12 hours; Preferably, in step I, the first sintering temperature is about 1600° C. to about 1800° C., and the sintering time is about 12 hours; Preferably, in step II, the first sintered mixture is crushed to a particle size of 50 to 100 μm; Preferably, in step II, the second sintering temperature is about 3000° C. to about 3100° C., and the sintering time is 12 hours; In step IV, the drying conditions are not limited and can be natural drying or heat drying; In step IV, screening is performed by mechanical screening or manual screening; Preferably, in step IV, the washing solvent is water; Preferably, in step IV, the particle size of the cubic boron carbide particles obtained by screening is 30 to 40 nm.

4. The ceramic abrasive composition according to any one of claims 1 to 3, comprising the following components in parts by weight: 15-45 parts of aluminum oxide, 15-25 parts of cubic silicon carbide, 1-2 parts of silicon dioxide, 6-9 parts of sintering additives, 1-2 parts of iron oxide, 2-5 parts of wetting agent, 3-5 parts of vanadium pentoxide, 1-3 parts of zirconium oxide and 5-15 parts of water; Preferably, the ceramic abrasive composition comprises the following components in parts by weight: 20-40 parts of aluminum oxide, 15-20 parts of cubic silicon carbide, 1.5-2 parts of silicon dioxide, 5-8 parts of sintering additives, 1.5-2 parts of iron oxide, 3-4 parts of wetting agent, 3-4 parts of vanadium pentoxide, 2-3 parts of zirconium oxide and 10-15 parts of water.

5. The ceramic abrasive composition according to claim 1 or 4, characterized in that The aluminum oxide is α-aluminum oxide; Also preferably, the particle size of the α-alumina is 50 to 200 nm, more preferably 50 to 100 nm; Preferably, the sintering additive is selected from one of magnesium oxide and calcium oxide or the two in any ratio; Preferably, the wetting agent is selected from one of dextrin and sodium carboxymethyl cellulose or the two in any ratio.

6. A method for preparing a ceramic abrasive, using the ceramic abrasive composition according to any one of claims 1 to 5 as a raw material, comprising the following steps: S1. The components are mixed in parts by weight and pressed to obtain a green body; S2. The green body obtained in step S1 is first pre-fired in stages at about 40°C to about 100°C for a total of about 10 to 24 hours, and then continuously roasted in stages at about 800°C to about 1500°C for a total of about 60 to 240 minutes; the roasted product is immediately water quenched, then ball-milled and dried, and sieved according to particle size to obtain ceramic abrasives of different particle size ranges.

7. The preparation method according to claim 6, characterized in that In step S1, during the pressing process, the pressure is about 100-150 MPa, and the pressure is maintained for about 30-60 minutes.

8. The preparation method according to claim 6, characterized in that In step S2, the continuous segmented pre-burning is performed, and the temperature rise program is: First, heat from room temperature to about 40°C, keep warm for about 2-3 hours, then increase the temperature by about 10°C, keep warm for about 2-3 hours, until the temperature reaches about 100°C, keep warm for about 2-3 hours; Preferably, the heating program for continuous staged pre-firing is: room temperature → about 40°C, keep warm for about 2 to 3 hours; about 40°C → about 50°C, keep warm for about 2 to 3 hours; about 50°C → about 60°C, keep warm for about 2 to 3 hours; about 60°C → about 70°C, keep warm for about 2 to 3 hours; about 70°C → about 80°C, keep warm for about 2 to 3 hours; about 80°C → about 90°C, keep warm for about 2 to 3 hours; about 90°C → about 100°C, keep warm for about 2 to 3 hours.

9. The preparation method according to claim 6, characterized in that In step S2, the continuous segmented roasting is a three-stage continuous roasting; the process conditions of each stage roasting are: First calcination, temperature is about 800℃ to about 900℃, and calcination time is about 20 to about 30 minutes; The second calcination temperature is about 1000°C to about 1200°C, and the calcination time is about 30 to about 120 minutes; The third calcination is performed at a temperature of about 1300° C. to about 1500° C. and a calcination time of about 30 to about 60 minutes.

10. The preparation method according to claim 9, characterized in that The first calcination is performed at a temperature of about 800° C. to 850° C. for about 30 minutes; Preferably, the second calcination is performed at a temperature of about 1100° C. to 1200° C. and for a time of about 60 to about 120 minutes; Preferably, the third calcination is performed at a temperature of about 1400° C. to 1450° C. and for about 60 minutes. Also preferably, the heating rate to the first calcination temperature is about 5 to 10°C / min, more preferably about 5 to 8°C / min; Preferably, the heating rate to the second calcination temperature is about 10-20°C / min, more preferably about 15-20°C / min; Preferably, the heating rate to the third calcination temperature is about 10-20° C. / min, more preferably about 15-20° C. / min.

11. The preparation method according to claim 6, characterized in that In step S2, the drying is oven drying at a temperature of about 80°C to about 120°C, more preferably about 100°C.

12. A ceramic abrasive prepared by the preparation method according to any one of claims 6 to 11.

13. A ceramic abrasive belt, comprising a binder layer, an abrasive layer, and a resin layer sequentially provided on a substrate, wherein the abrasive layer is formed of the ceramic abrasive according to claim 12; Preferably, the abrasive layer has a thickness of about 0.1 to 0.3 mm; The adhesive layer and the resin layer are each independently formed of bismaleimide resin glue or phenolic modified epoxy resin; The substrate can be any synthetic fiber material that can be used as a sanding belt substrate, preferably a pure polyester grey cloth.

14. The method for preparing the ceramic abrasive belt according to claim 13, comprising the following steps: One side of the substrate is fully coated with bismaleimide resin glue or phenolic modified epoxy resin; then the ceramic abrasive described in this application is evenly covered on the entire surface of the adhesive layer by gravity sand planting or electrostatic sand planting to form an abrasive layer about 0.1 to 0.3 mm thick; finally, a layer of bismaleimide resin glue or phenolic modified epoxy resin is coated on the surface of the abrasive layer to obtain.

15. Use of the ceramic abrasive belt according to claim 13 or the ceramic abrasive belt obtained by the preparation method according to claim 14 in rail grinding.