Patent Description:
From the Polish description of the application of the invention <CIT> is known a method of obtaining a highly refractory composite from boron carbide and an intermetallic compound of the Ti-Si system, relaying on mixing starting powders in the form of boron carbide B<NUM>C, the intermetallic compound of the Ti-Si system and carbon C in an alcohol environment, forming shaped pieces from the mixture of powders and subjecting them to sintering, in which titanium silicide Ti<NUM>Si<NUM> and carbon C are added to the boron carbide B<NUM>C powder, in the molar ratio B<NUM>C:Ti<NUM>Si<NUM>:C of <NUM>:<NUM>:<NUM>. Then, the whole is mixed in the isopropyl alcohol environment for <NUM>-<NUM> minutes and dried until the complete evaporation of the alcohol for <NUM>-<NUM> minutes, after which the shaped pieces are pre-formed and subjected to isostatic pressing under a pressure of <NUM>-<NUM> MPa. The achieved moulded pieces are subjected to the free sintering process in argon atmosphere at a temperature of <NUM>-<NUM>, with a temperature increase of <NUM>-<NUM>/minute and a holding time of <NUM>-<NUM> minutes at a maximum temperature, achieving the TiB<NUM>-TiC-SiC-Ti<NUM>Si<NUM> composite consisting of <NUM>-<NUM>% of TiB<NUM>, <NUM>-<NUM>% of TiC, <NUM>-<NUM>% of SiC, and <NUM>-<NUM>% of Ti<NUM>Si<NUM> by weight. The efficiency of the process is at least <NUM>%.

It is known from the Polish description of the application of the invention PL425041A1 a ceramic composite of the group of UHTC materials with the matrix of hafnium diboride HfB<NUM> and a method of manufacturing thereof. The method is characterized in that the additives in the form of silicon carbide SiC and/or boron carbide B<NUM>C in the amount from <NUM>% by volume to <NUM>% by volume and graphene nanoflakes having an average particle size <<NUM> in the amount from <NUM>% by volume to <NUM>% by volume are introduced into the powder with hafnium diboride HfB<NUM> in the amount from <NUM>% by volume to <NUM>% by volume and the starting mixture is subjected to high-pressure sintering using the HPHT method under the pressure of <NUM> GPa at the temperature of <NUM>±<NUM>.

It is known from the European patent description <CIT> a method of manufacturing high-density UHTC composites in the ZrB<NUM>-SiC-ZrC system. This method is characterized in that zirconium powders having a purity higher than <NUM>% and a particle size less than <NUM> are dry mixed with boron carbide powder having a purity higher than <NUM>% and a particle size less than <NUM>, and then mixed with graphite powder having a particle size ranging from <NUM> to <NUM>. The mixture thus achieved is subjected to the SHS synthesis, and then sintered using the Electric Current Activated Sintering (ECAS) method at temperatures ranging from <NUM> to <NUM>, with a holding for <NUM> to <NUM> minutes at a maximum temperature.

It is known from the Chinese patent description <CIT>a method of manufacturing UHTC composites from the B<NUM>C-ZrB<NUM> system. This method is characterized in that composite powder is produced in the sintering process of the mixture of powders of B<NUM>C, ZrB<NUM>, carbon black and metallic silicon. The mixture of powders is isostatically pressed under a pressure ranging from <NUM> to <NUM> MPa, and then freely sintered at a temperature ranging from <NUM> to <NUM> with a holding for <NUM> to <NUM> hours at a maximum temperature. <NPL>) describe a TiB<NUM>-TiC-SiC ternary composite and disclose the manufacture of <NUM> TiB<NUM> - x TiC - (<NUM>-x) SiC by reactive hot pressing, namely: mixing Si : B<NUM>C : Ti powders in a molar ratio (<NUM>-x) : <NUM> : (<NUM>+x), i.e. <NUM> : <NUM>: <NUM> and <NUM> : <NUM> : <NUM> ; hot pressing at <NUM> under <NUM> MPa in vacuum, for <NUM> with a heat rate of <NUM>/min.

The purpose of the method according to the invention is to increase heat resistance of a cutting tool while maintaining high hardness.

The gist of the method of manufacturing a cutting tool from a highly refractory composite obtained from boron carbide and an intermetallic compound of the Ti-Si system, relaying on mixing starting powders in the form of boron carbide (B<NUM>C), the intermetallic compound of the Ti-Si system, carbon C and boron B in the isopropyl alcohol environment, forming shaped pieces from the mixture of powders and subjecting them to sintering, relay on that the highly refractory composite contains titanium silicide TiSi or TiSi<NUM> as the intermetallic compound of the Ti-Si system in the molar ratio B<NUM>C:TiSi/TiSi<NUM>:C:B of <NUM>:<NUM>:<NUM>:<NUM>. The obtained TiB<NUM>-TiC-SiC-TiSi composite containing titanium silicide TiSi has <NUM>-<NUM>% by weight of TiB<NUM>, <NUM>-<NUM>% by weight of TiC, <NUM>-<NUM>% by weight of SiC and <NUM>-<NUM>% by weight of TiSi, while the obtained TiB<NUM>-TiC-SiC-TiSi<NUM> composite containing titanium silicide TiSi<NUM> has <NUM>-<NUM>% by weight of TiB<NUM>, <NUM>-<NUM>% by weight of TiC, <NUM>-<NUM>% by weight of SiC and <NUM>-<NUM>% by weight of TiSi<NUM>. The sintering process of the formed shaped pieces is carried out by the spark plasma sintering method SPS under the protection of argon at a temperature of <NUM>-<NUM>, with a temperature increase of <NUM>-<NUM> per minute, with a holding time of <NUM>-<NUM> minutes and under the pressure of <NUM> MPa or by the hot pressing method at a temperature of <NUM>-<NUM>, with the temperature increase of <NUM>, with the holding time of <NUM> minutes and under the pressure of <NUM> MPa.

The use of titanium silicide TiSi or TiSi<NUM> as the intermetallic compound of the Ti-Si system in a highly refractory composite made it possible to eliminate unreacted carbon formed as the result of the decomposition of boron carbide (B<NUM>C) during the synthesis, while simultaneously achieving the largest possible amount of the TiB<NUM> phase having the highest melting point (T=<NUM>) among the components of the composite and the TiC phase (T=<NUM>), which improved the refractoriness of the produced composite, while simultaneously increasing its hardness. The preferable phase composition of the composite, i.e. the high content of TiB<NUM> and TiC phases, compared to the composites known from the state of the art and produced from boron carbide and an intermetallic compound of the Ti-Si system, allows the composite according to the invention to work at high temperatures for a longer time while maintaining preferable mechanical properties. On the other hand, the conduction of the sintering process using the spark plasma sintering method SPS under the protection of argon makes it possible to significantly lower the synthesis temperature to <NUM>, and thus reduce the costs of tools manufacturing.

The obtained shaped pieces of cutting tool obtained by the method according to the invention are characterized by high hardness as measured by the Vickers method and ranging from <NUM> to <NUM> (GPa) and can work up to a temperature of <NUM>-<NUM> at the edge of cutting tool without the use of coolant in the form of water. The proposed shaped pieces can be made with different geometry of the blade shape through mechanical working, and their average density is up to <NUM>%. The obtained cutting tools are characterized in that they can be regenerated from <NUM>-<NUM> times by using the additive of boron and carbon to the composition and re-sintering the obtained shaped pieces by using laser treatment under the protection of argon or by mechanical re-working the shaped pieces and removing damaged or deformed surfaces. Due to the high abrasion resistance of the obtained composites, the average friction factor can be determined at the level of <NUM>-<NUM>.

The following powders were prepared to obtain the composite: boron carbide B<NUM>C, titanium silicide TiSiz, carbon C in the form of P-<NUM> technical carbon black (Tuymazy) and amorphous boron, which consisted of three phases: beta boron, boric acid and boron. Commercial boron carbide B<NUM>C powder (Boron carbide B4C GRADE HS by Höganäs) containing the following phases: B<NUM>C<NUM> (<NUM>%) and graphite (<NUM>%) was used. To produce the TiSi<NUM> powder, the process of self-developing high-temperature synthesis (SHS) was used, as described in the publication by <NPL>, according to which the powders of Ti and Si were used in the molar ratio of <NUM>:<NUM>. The mixture of powders was placed in a reactor with argon atmosphere under the overpressure of <NUM> atm. The SHS synthesis reaction was initiated locally by the heat released during current flow, through a graphite foil placed in the mixture of powders. The current intensity was <NUM> A, and the flow time was <NUM> minute. The produced titanium silicide TiSi<NUM>, carbon C in the form of P-<NUM> technical carbon black (Tuymazy) and amorphous boron were added to the boron carbide B<NUM>C powder, in the molar ratio B<NUM>C:TiSi<NUM>:C:B of <NUM>:<NUM>:<NUM>:<NUM>, and the whole mixture was then stirred in a rotary-vibrating mill in the isopropyl alcohol environment for <NUM> minutes, after which it was dried until the complete evaporation of the alcohol for <NUM> minutes. The obtained powders were preformed into disks having the diameter of <NUM> and the height of <NUM> and subjected to isostatic pressing under the pressure of <NUM> MPa. The achieved moulded pieces were subjected to the sintering process by the spark-plasma method SPS in argon (Ar) atmosphere under the protection of argon, at the temperature of <NUM>, with the temperature increase of <NUM> per minute, with the holding time of <NUM> minutes and under the pressure of <NUM> MPa. The TiB<NUM>-TiC-SiC-TiSi<NUM> composite containing titanium silicide TiSi<NUM>, obtained by the method according to the invention, had the following phase composition: <NUM> % by weight of TiB<NUM>, <NUM> % by weight of TiC, <NUM> % by weight of SiC, and <NUM> % by weight of TiSi<NUM>. The thus obtained moulded pieces of the composite having the composition as above in the form of the cylinder having the diameter of <NUM> and the height of <NUM> were subjected to mechanical working.

The manufactured tool in the form of a multi-blade plate having the RNGN1204 geometry, intended for use in a cutting device, had high hardness of <NUM> (GPa) as measured by the Vickers method, wherein during the test it worked at the temperature of <NUM> without the use of coolant in the form of water. The obtained cutting tools are characterized in that they can be regenerated by using the additive of boron and carbon to the composition and re-sintering the obtained shaped pieces, it is possible to use laser treatment under the protection of argon or by mechanical re-working the shaped pieces and removing damaged or deformed surfaces. Due to the high abrasion resistance of the obtained composites, the average friction factor can be determined at the level of <NUM>. The use of intermetallics and starting products in the form of boron carbide (B<NUM>C), boron (B) and carbon (C) confirms the occurrence of the reaction sintering during the synthesis, which makes it possible to achieve a density of the obtained composites at the level of <NUM>%.

The following powders were prepared to obtain the composite: boron carbide B<NUM>C, titanium silicide TiSi, carbon C in the form of P-<NUM> technical carbon black (Tuymazy) and amorphous boron, which consisted of three phases: beta boron, boric acid and boron. Commercial boron carbide B<NUM>C powder (Boron carbide B<NUM>C GRADE HS by Höganäs) containing the following phases: B<NUM>C<NUM> (<NUM>%) and graphite (<NUM>%) was used. To produce the TiSi powder, the process of self-developing high-temperature synthesis (SHS) was used, as described in the publication by <NPL>, according to which the powders of Ti and Si were used in the molar ratio of <NUM>:<NUM>. The mixture of powders was placed in a reactor with argon atmosphere under the overpressure of <NUM> atm. The SHS synthesis reaction was initiated locally by the heat released during current flow, through a graphite foil placed in the mixture of powders. The current intensity was <NUM> A, and the flow time was <NUM> minute. The produced titanium silicide TiSi, carbon C in the form of P-<NUM> technical carbon black (Tuymazy) and amorphous boron were added to the boron carbide B<NUM>C powder, in the molar ratio B<NUM>C:TiSi:C:B of <NUM>:<NUM>:<NUM>:<NUM>, and the whole mixture was then stirred in a rotary-vibrating mill in the isopropyl alcohol environment for <NUM> minutes, after which it was dried until the complete evaporation of the alcohol for <NUM> minutes. The obtained powders were preformed into disks having the diameter of <NUM> and the height of <NUM> and subjected to isostatic pressing under the pressure of <NUM> MPa. The achieved moulded pieces were subjected to the sintering process by the spark-plasma method SPS in argon (Ar) atmosphere under the protection of argon, at the temperature of <NUM><NUM>, with the temperature increase of <NUM> per minute, with the holding time of <NUM> minutes and under the pressure of <NUM> MPa. The TiB<NUM>-TiC-SiC-TiSi composite containing titanium silicide TiSi, obtained by the method according to the invention, had the following phase composition: <NUM>% by weight of TiB<NUM>, <NUM>% by weight of TiC, <NUM>% by weight of SiC and <NUM>% by weight of TiSi. The thus obtained moulded pieces of the composite having the composition as above in the form of the plate with the square base having the side of <NUM> and the height of <NUM> were subjected to mechanical working.

The following powders were prepared to obtain the composite: boron carbide B<NUM>C, titanium silicide TiSiz, carbon C in the form of P-<NUM> technical carbon black (Tuymazy) and amorphous boron, which consisted of three phases: beta boron, boric acid and boron. Commercial boron carbide B<NUM>C powder (Boron carbide B<NUM>C GRADE HS by Höganäs) containing the following phases: B<NUM>C<NUM> (<NUM>%) and graphite (<NUM>%) was used. To produce the TiSi<NUM> powder, the process of self-developing high-temperature synthesis (SHS) was used, as described in the publication by <NPL>, according to which the powders of Ti and Si were used in the molar ratio of <NUM>:<NUM>. The mixture of powders was placed in a reactor with argon atmosphere under the overpressure of <NUM> atm. The SHS synthesis reaction was initiated locally by the heat released during current flow, through a graphite foil placed in the mixture of powders. The current intensity was <NUM> A, and the flow time was <NUM> minute. The produced titanium silicide TiSi<NUM>, carbon C in the form of P-<NUM> technical carbon black (Tuymazy) and amorphous boron were added to the boron carbide B<NUM>C powder, in the molar ratio B<NUM>C:TiSi<NUM>:C:B of <NUM>:<NUM>:<NUM>:<NUM>, and the whole mixture was then stirred in a rotary-vibrating mill in the isopropyl alcohol environment for <NUM> minutes, after which it was dried until the complete evaporation of the alcohol for <NUM> minutes. The obtained powders were preformed into disks having the diameter of <NUM> and the height of <NUM> and subjected to isostatic pressing under the pressure of <NUM> MPa. The achieved moulded pieces were subjected to the sintering process by the hot pressing method at the temperature of <NUM>, with the temperature increase of <NUM> per minute, with the holding time of <NUM> minutes and under the pressure of <NUM> MPa. The TiB<NUM>-TiC-SiC-TiSi<NUM> composite containing titanium silicide TiSi<NUM>, obtained by the method according to the invention had, the following phase composition: <NUM>% by weight of TiB<NUM>, <NUM>% by weight of TiC, <NUM>% by weight of SiC and <NUM>% by weight of TiSi<NUM>. The thus obtained moulded pieces of the composite having the composition as above in the form of the cylinder having the diameter of <NUM> and the height of <NUM> were subjected to mechanical working.

The following powders were prepared to obtain the composite: boron carbide B<NUM>C, titanium silicide TiSi, carbon C in the form of P-<NUM> technical carbon black (Tuymazy) and amorphous boron, which consisted of three phases: beta boron, boric acid and boron. Commercial boron carbide B<NUM>C powder (Boron carbide B<NUM>C GRADE HS by Höganäs) containing the following phases: B<NUM>C<NUM> (<NUM>%) and graphite (<NUM>%) was used. To produce the TiSi powder, the process of self-developing high-temperature synthesis (SHS) was used, as described in the publication by <NPL>, according to which the powders of Ti and Si were used in the molar ratio of <NUM>:<NUM>. The mixture of powders was placed in a reactor with argon atmosphere under the overpressure of <NUM> atm. The SHS synthesis reaction was initiated locally by the heat released during current flow, through a graphite foil placed in the mixture of powders. The current intensity was <NUM> A, and the flow time was <NUM> minute. The produced titanium silicide TiSi<NUM>, carbon C in the form of P-<NUM> technical carbon black (Tuymazy) and amorphous boron were added to the boron carbide B<NUM>C powder, in the molar ratio B<NUM>C:TiSi:C:B of <NUM>:<NUM>:<NUM>:<NUM>, and the whole mixture was then stirred in a rotary-vibrating mill in the isopropyl alcohol environment for <NUM> minutes, after which it was dried until the complete evaporation of the alcohol for <NUM> minutes. The obtained powders were preformed into disks having the diameter of <NUM> and the height of <NUM> and subjected to isostatic pressing under the pressure of <NUM> MPa. The achieved moulded pieces were subjected to the sintering process by the hot pressing method at the temperature of <NUM>, with the temperature increase of <NUM> per minute, with the holding time of <NUM> minutes and under the pressure of <NUM> MPa. The TiB<NUM>-TiC-SiC-TiSi composite containing titanium silicide TiSi, obtained by the method according to the invention, had the following phase composition: <NUM>% by weight of TiB<NUM>, <NUM>% by weight of TiC, <NUM>% by weight of SiC and <NUM>% by weight of TiSi. The thus obtained moulded pieces of the composite having the composition as above in the form of the square having the side of <NUM> and the height of <NUM> were subjected to mechanical working.

Claim 1:
A method of manufacturing a cutting tool from a highly refractory composite obtained from boron carbide and an intermetallic compound of the Ti-Si system, relaying on mixing starting powders in the form of boron carbide (B<NUM>C), the intermetallic compound of the Ti-Si system, carbon C and boron B in the isopropyl alcohol environment, forming shaped pieces from the mixture of powders and subjecting them to sintering and mechanical working, characterized in that the highly refractory composite contains titanium silicide TiSi or TiSi<NUM> as the intermetallic compound of the Ti-Si system, in the molar ratio B<NUM>C:TiSi/TiSi<NUM>:C:B of <NUM>:<NUM>:<NUM>:<NUM>, wherein the obtained TiB<NUM>-TiC-SiC-TiSi composite containing titanium silicide TiSi has <NUM>-<NUM>% by weight of TiB<NUM>, <NUM>-<NUM>% by weight of TiC, <NUM>-<NUM>% by weight of SiC and <NUM>-<NUM>% by weight of TiSi, while the obtained TiB<NUM>-TiC-SiC-TiSi<NUM> composite containing titanium silicide TiSi<NUM> has <NUM>-<NUM>% by weight of TiB<NUM>, <NUM>-<NUM>% by weight of TiC, <NUM>-<NUM>% by weight of SiC and <NUM>-<NUM>% by weight of TiSi<NUM>, and the sintering process of the formed shaped pieces is carried out by spark plasma sintering method SPS under the protection of argon, at a temperature of <NUM>-<NUM>, with a temperature increase of <NUM>-<NUM> per minute, with a holding time of <NUM>÷<NUM> minutes and under the pressure of <NUM> MPa or by the hot pressing method at a temperature of <NUM>-<NUM>, with the temperature increase of <NUM> per minute, with the holding time of <NUM> minutes and under the pressure of <NUM> MPa.