JP2704317B2 - Physical vapor deposition of titanium nitride on non-conductive substrates - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a process for physically depositing a refractory coating on a non-conductive substrate and a product made therefrom.

More particularly, the present invention relates to a process for physically depositing a titanium nitride coating on a ceramic substrate and a product made therefrom.

Description of Related Art Various methods for physically depositing a material on a substrate, such as a base metal, are well known. For example, gaseous species are physically deposited on metal substrates by evaporation, reactive evaporation, ion plating and sputtering.

An exemplary ion plating system for coating a substrate is described in U.S. Patent No. 3.329.601.
The system includes a metal source, a source of electrons, such as filament, and a vacuum chamber having a substrate material supported in a substrate holder that is negatively biased with respect to the plasma generated in the chamber. When driving, the chamber is evacuated first and then filled with an inert gaseous type such as Angong. The electrons are then emitted by a filament and a metal source. Some of the electrons collide with neutral molecules in the plasma, causing excitation and partial ionization of gaseous species. This state of the partially ionized and excited gaseous type, together with free electrons, is called a plasma. The excited particles emit photons when returning to a lower energy state, and a visible glow is observed around the substrate. Under the influence of the applied electric field, argon ions from the region of "brightness" accelerate and strike the biased substrate, effectively cleaning the substrate surface from dirt and increasing the substrate surface temperature. It is also possible to independently heat the substrate prior to ion bombardment. Once the cleaning is completed, a coated metal source, such as titanium, placed in a crucible is heated in a known manner to evaporate the coating material and place it in a glow discharge. The ionized metal is allowed to react during the ion plating process with a gaseous species such as ionized nitrogen. The ion plating process results in a uniform coating of a material such as titanium nitride on the substrate.

Titanium and / or titanium nitride coatings have been successfully applied to carburized carbide and tool steel substrates by physical vapor deposition. Examples of various processes for the physical deposition of coatings on cutting tools are described in U.S. Pat.
4.469.489; 4.406.669; 4.539.251 and 4.337.300.

However, ion plating of a titanium nitride coating on a ceramic substrate tends to form a charge on the substrate surface because the ceramic substrate is inherently electrically insulating. The bias voltage applied between the plasma and the ceramic substrate affects the adhesion of the titanium nitride coating. Insufficient biasing of the voltage due to charge buildup results in the coating peeling off the ceramic substrate, thereby producing a totally unsatisfactory coated ceramic.

To overcome the aforementioned problems, we have invented a new process for physically depositing a refractory coating on a non-conductive substrate. More specifically, the present invention utilizes an ion-plated physical vapor deposition process for coating titanium nitride on a suitable non-conductive substrate, such as a substrate made of a ceramic material or the like.
Sialon (Si-Al-ON) based ceramic substrate or Si
Al ₂ O ₃ based ceramic substrate containing ₃ N ₄ based ceramic substrate or Shirukonia and / or other or made of hard material and an alloy or Al ₂ O ₃ composite without the addition of these, such as silicon carbide whiskers Any suitable substrate such as can be coated according to the present invention. The present invention overcomes the ineffectiveness of the applied bias voltage between the plasma and the insulator and provides a process for depositing a titanium nitride coating on a non-conductive substrate.

It is therefore an object of the present invention to provide a tool or article with a coating having improved adhesion by a physical vapor deposition process such as ion plating.

Another object of the present invention is high abrasion resistance, heat resistance,
And to provide a coated article or tool having corrosion resistance.

Yet another object of the present invention is to provide cutting tools, wear-resistant parts and decorative articles having improved wear, corrosion and corrosion resistance.

SUMMARY OF THE INVENTION Briefly, the present invention proposes a tool insert coated by physical vapor deposition using an applied electrical bias. The coated tool has a surface conductive ceramic substrate on which a first layer of titanium is deposited by physical vapor deposition to provide an electrical bias between the conductivity of the ceramic substrate and the physical vapor deposition. Giving it increased effectiveness. The coating also includes a second layer of titanium nitride deposited and deposited over the first layer by physical vapor deposition.

Briefly, the present invention also proposes a method for physical vapor deposition of a heat resistant coating, preferably a titanium nitride coating, on a non-conductive substrate such as a ceramic substrate. This method cleans the surface of a non-conductive substrate, then deposits a first layer of a refractory metal such as titanium by physical vapor deposition, and then deposits a second layer of a refractory metal compound such as titanium nitride.
Depositing the layer to create a coated non-conductive substrate with enhanced coating adhesion.

A particular advantage created by the products and methods of the present invention is an improved adhesion between the non-conductive substrate of ceramic and the coating deposited by physical vapor deposition. Preferably, the level of adhesion is 45k as determined by an indentation adhesion test
g or more, more preferably 60 kg
Is equal to or greater than

The first layer increases the conductivity of the non-conductive substrate so that electrical bias in the ion plating process is effective. Ion-plated titanium nitride coatings on ceramic substrates, such as ceramic insert cutting tools, can be cast iron or nickel-based superalloys in the case of Si-Al-ON based ceramic substrates, or Al.
It has been found that reducing the friction coefficient between the cutting tool and the work piece, such as carbon and heat resistant steel, and reducing the flank wear in the case of ₂ O ₃ based ceramic substrate, reduce the frictional force, titanium nitride It acts as an obstruction to diffusion migration between the insert cutting tool and the work piece due to the chemical stability of the insert, thereby reducing the problems of tool surface dents, flank wear and notches.

BRIEF DESCRIPTION OF THE DRAWINGS Further features, other objects and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the drawings. In this drawing: FIG. 1 is a perspective view of a Kenloc style insert, and FIG. 2 is a perspective view of a Kendex style insert.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Although the present invention has been described with reference to a physical vapor deposition process of ion plating for coating non-conductive ceramic substrates, the present invention is also directed to almost any suitable non-conductive substrate. Also used for coating. The non-conductive substrate is coated by first cleaning the surface of the non-conductive substrate and then depositing a first layer of titanium on the surface of the cleaned substrate. A second layer of titanium nitride is deposited over the first layer to yield a coated substrate having an outer coating having enhanced adhesion.

In an ion plating physical vapor deposition process, a non-conductive substrate acts as an electrical insulator, as opposed to being electrically conductive, where charge builds up on the substrate surface. The formation of charge effectively reduces the bias applied on the substrate, which in turn results in a reduced adhesion of the titanium nitride coating to the non-conductive substrate.

It will be appreciated that the physical vapor deposition process of the present invention also includes, but is not limited to, ion plating, including evaporation, reactive evaporation, ion plating, sputtering and magnetron sputtering. However, in a preferred embodiment, the titanium nitride layer is deposited by ion plating, wherein the material to be deposited is energized as positive ions by applying a negative acceleration voltage to the substrate. As used herein, ion plating is a process that occurs on a substrate and is virtually independent of the method used to generate the ions that bind to form the coating compound. For example, various methods for generating metal ions are used for ion plating, such as thermal evaporation ion plating, sputter ion plating, arc evaporation ion plating, and others.

The present invention can be applied to the production of coated articles, such as cutting tool inserts with non-conductive ceramic insert substrates.

Cutting tool inserts are also manufactured by conventional ceramic powder processing techniques, densified by hot pressing or pressureless sintering. The ceramic insert substrate is
Ceramic cutting insert with Si-Al-ON substrate, Al
KYON2000, KYON3000 by Kenna Metal Company for ₂ O ₃ based ceramic cutting inserts and other products
And those commercially available under the designation KO90, but are not limited thereto. KYON and KO90 consist of hard ceramic material in the form of a cutting tool insert, such as a ceramic material in the form of a cutting tool insert and wear-resistant parts and inserts used in dies or tools for cutting or forming materials. Kennametal is a registered trademark for wearable parts.

Si-Al-ON grade cutting inserts are beta-based Si
It can be -Al-ON, alpha-based Si-Al-ON or mixtures thereof and can also contain a glassy phase ranging from 0 to 10 percent by weight. KYON3000 is a chemical formula
Beta-based Si-Al-O represented by Si ₆ -zAlzOzN ₈ -z
N, where z has a value greater than 0 but less than 4.2. Beta-based Si-Al-
For a description of ON materials, reference is made to US Patent No. 4.127.416, which is hereby incorporated by reference. KYON2000, is mainly for alpha and beta-based Si-Al-
ON. Alpha-based Si-Al-ON has the chemical formula Mx (Si,
Al) ₁₂ (O, N) ₁₆ , where x
Is greater than 0 and less than z and M is Li, Na, Ca, M
It is at least one selected from the group consisting of g, Y and some rare earth elements. For a complete description of alpha-based, beta-based Si-Al-ON compositions useful for cutting tool inserts, see U.S. Pat.
Reference is made to Issue 4.547.470, which is incorporated herein by reference.

Among the many ceramic cutting inserts designed according to the present invention based on Al ₂ O ₃ are cutting inserts having a microstructure of Al ₂ O ₃ , among which SiC and / or refractory metals (titanium) , hafnium, Vuanajiumu, tantalum, zirconium, and the compound of niobium) (oxides, nitrides, carbides and nitrides) such as, preferably, TiC and / or ZrO ₂ particles and / or SiC or Ti
C whiskers are dispersed there. As disclosed in U.S. patent application Ser.No. 07 / 266.719, filed Nov. 3, 1988, assigned to Kennametal by Merlottra, alumina-based ceramic cutting inserts are approximately 1.
5 to 12 v / o (volume percent) silicon carbide whiskers and about 7.5 to 17.5 v / o zirconia are provided dispersed in an alumina-based matrix. Another
Al ₂ O ₃ based ceramic cutting insert is one of Merota
988, November 3 days described in commonly assigned U.S. patent application No. 07 / 266.721 and No. 07 / 266.735 to apply Kennametal Inc. cage, 17.5V from Al ₂ O ₃ based cutting insert of about 1.5 /
o silicon carbide whiskers, from about 5 to 17.5 v / o zirconia, the residue of the addition of magnesium, oxide or other magnesium oxide and at least 4 v / o tetragonal zirconia. Yet another Al ₂ O ₃ -based cutting insert is described in US patent application Ser. No. 07 / 266.714, assigned to Kennametal, filed Nov. 3, 1988, by Melota. Al ₂ O ₃ based cutting inserts described in U.S. patent application Ser.No. 07 / 266.714 are 1.5 to 37.5 v / o silicon carbide housker, about 5 to 17.5 v / o zirconia, magnesium, oxide or other magnesium. It contains the residue of the oxide addition and at least 2 v / o of tetragonal zirconia. Silicon carbide whiskers (SiC
w) is discontinuous and single crystal silicon carbide (S
iC) Fiber is a known technique. The silicon carbide whiskers used are of the commercially available brand used in the past for alumina-based cutting inserts.

On the Al ₂ O ₃ -SiC composite reinforced by whiskers
The TiN layer presents a chemically inert obstruction that prevents the reaction of the SiC whiskers with the steel work piece.

One example of a ceramic composition comprising an alumina matrix with titanium carbide (TiC) whiskers dispersed therein is disclosed in U.S. Pat. No. 4,852.99 assigned to Kennametal.
No. 9 is referenced.

U.S. Patent No. 4.852.999 and U.S. Patent Application Nos. 07 / 266.719; 07 / 266.721;
07 / 266.735 and 07 / 266.714 are hereby incorporated by reference.

Al ₂ O ₃ A preferred composition of the base of the ceramic insert is not or added added sintering auxiliary additives about 5-10v / o
Zirconia refractory metal compound particles and / or whiskers and / or SiC whiskers.

Al ₂ O ₃ based ceramic insert is prepared by grinding to a fine finish surfaces of the insert. Dye penetrants of the type well known in the art are added to the insert to aid in visual inspection of the abrasive finish and check of the abrasive clutch. The dye penetrant is soap and about 56
It is preferably removed by ultrasonic cleaning in a mixture of warm water at about 1 hour. The insert is then baked in an air-heated oven usually used for drying operations to completely evaporate the washing mixture. The use of the dye penetrant and the washing step used to remove the dye penetrant from the insert can be omitted and does not affect the present invention.

The applicant may heat the surface of the substrate, first thoroughly clean it under vacuum, ion-etch the substrate for a sufficient length of time to provide a stain-free surface, and then apply the non-conductive substrate It has been discovered that by depositing a first layer of titanium thereon, the aforementioned problems associated with electrical conductivity are overcome.

The ceramic substrate is evacuated and then placed in a chamber filled with an inert gas such as argon. The inert gas is partially ionized and excited in the plasma as described above. The ceramic substrate is then cleaned by heating and ion etching. The ceramic substrate is heated by suitable means according to known techniques, such as electron bombardment. In electron bombardment, a positive potential is applied to the substrate in the chamber to attract the electrons from the gaseous plasma.
Under a vacuum of about 10 ^-3 torr, the substrate is heated by electrons that strike the surface of the substrate and remove various oxides from the substrate surface. Si-Al-ON-based substrate and Al ₂ O ₃ based substrate is preferably heated to a temperature of about 400 ° C..
Although there is a charge formation during the electron bombardment,
It has been observed that the current density of the electrons between the substrate and the plasma is high enough to overcome this formation, thus allowing surface heating by electron bombardment. The substrate is then subjected to ion etching, where the polarity of the substrate is increased by applying heavy argon ions, typically used for ion etching, to the substrate from a gaseous plasma to remove surface contaminants such as grease, dirt, etc. It is reversed to a negative potential to attract. Depending on the temperature, the surface area of the insert to be cleaned, and the degree of contamination, the applicant may require a ceramic substrate in vacuum for about 4 hours to 6 hours.
Found to be cleaned after a period of time range.

For example, to achieve substantially free of contaminants from the substrate, the higher the heating temperature, the shorter the required cleaning time.

A first layer of titanium is then deposited on the evaporated and cleaned ceramic substrate. The titanium is evaporated and deposited for about 10 minutes by any suitable means known in the art, such as resistance heating, electron bombardment or radio frequency induction heating. The electrical bias during the physical vapor deposition process is effective because the deposited titanium layer increases the electrical conductivity of the ceramic substrate surface at the deposited temperature.

A second layer of titanium nitride is then deposited over the first layer. A second layer of titanium nitride is deposited by introducing nitrogen gas into the vacuum chamber to react with the titanium there to form titanium nitride. The negative bias of the titanium-coated substrate results in a glow discharge which increases the kinetic energy of the deposited titanium nitride material and results in the deposition of various thicknesses of the titanium nitride coating. As a result of the present invention, an excellent coating adhesive strength to the ceramic substrate and a high-density coated structure can be obtained.

The invention of the present application is further illustrated by considering the following examples: Kenloc and Kend as shown in FIGS.
ex-style Kennametal Si-Al-ON and Kennametal
Several indexable metal cutting inserts of Al ₂ O ₃ grade were each coated with titanium nitride. As shown in FIGS. 1 and 2, each metal cutting insert 10 has a flank surface 12, a rake surface 14, and a cutting blade 16 at the junction of the flank and rake surfaces. There is an opening 18 through the rake face of the Kenloc style insert shown in FIG. Kenloc and Kendex are registered trademarks of Kennametal for cutting tools with indexable cutting inserts and carbide cutting tools, respectively.

The ceramic substrate was coated in a BARTAS BAI830 physical vapor deposition system with a vertically movable pot. The ceramic substrate was heated under a vacuum of about ^10-3 Torr for a period of about 3 to 6 hours. From there, titanium was deposited on the cleaned ceramic substrate. Titanium nitride was then deposited on the titanium coating. Next, the thickness and adhesion of the titanium nitride coating on the flank surface of the insert was evaluated. The thickness of the coating and the degree of adhesion were similar when using the present invention to those found in a cemented carbide substrate coated with titanium nitride by physical vapor deposition.

Example 1 Several ceramic metal cutting inserts of the SNGA-433 type consisting of Kyon2000 and Kgon3000 were individually heated in a separate test to a temperature of about 400 ° C. for about 4 hours and subsequently Barthour B
A half hour ion etch was performed at a pressure of about 10 ^-3 Torr in the AI830 system. The first layer of titanium applies an arc current of about 125 amps to the titanium in the crucible for about 5 minutes as the crucible moves vertically in the vacuum chamber, and then increases the arc current to 200 amps. The insert was coated on the surface by holding for about 5 minutes. Thereafter, nitrogen gas was introduced into the system for about 80 minutes to form a titanium nitride coating on the insert surface.

Although the thickness of the titanium layer was too thin to measure with an optical microscope, the presence of the titanium layer was observed by transmission electron microscopy. The thickness of the titanium nitride coating is specified in a paper by PK Merlotla, DT Quint and GJ Vuolhue, pp. 757 of the 9th International Conference on CVD, 1984, Electrochemical Society of Pennington, New Jersey. Abrasion flaw thickness test ". This paper is incorporated herein by reference. The thickness of the titanium nitride coating was measured to be about 2-3 microns on the face of the flank. The level of adhesion of the coating is hereby incorporated by reference. “Shin Solid Film”,
154 (1987) 361-375. The thickness and degree of adhesion of the coating according to the present invention were similar to those found on physically vapor-deposited titanium nitride coated cemented carbide substrates. The adhesive belt was determined to be equal to or greater than 60 kg for each tested sample.

Example 2 Several ceramic metal cutting inserts of the SNGA-433 type, consisting of Kyon2000 and Kyon3000, were heated in a separate test here to about 400 ° C. for about 3 hours, and subsequently to BAL83 from Baltour.
A 1/2 hour ion etch was performed in the 0 system at a pressure of about 10 ^-3 Torr. The first layer of titanium is about
The surface of the insert was coated by applying an arc current of 125 amps to the titanium in the crucible for about 5 minutes as the crucible moved vertically in the vacuum chamber. The arc current was then raised to about 200 amps and nitrogen gas was immediately introduced into the system for about 85 minutes, forming a titanium nitride coating on the insert surface.

The thicknesses of the titanium nitride coatings can be found in the Electrochemical Society of Pennington, New Jersey, 1984, 9th International Conference on CVD, pp. 757 of the 9th CVD, incorporated herein by reference.
Determined by the "Thickness test after ball abrasion" specified in a dissertation by PK Mellowtra, DT Kind and GJ Vuolhue. The thickness of the titanium nitride coating was measured to be about 2-3 microns on the flank face. The level of adhesion of the coating was determined by the dent test specified in Example 1. Adhesion was not constant with some loss. The level of adhesion may be reduced due to shorter heating cycles as well as insufficient removal of surface contaminants as a result of insufficient titanium layer coverage.
It was determined to be less than or equal to 30 kg. It is believed that surface contaminants affected the coating of the titanium layer on the substrate surface and in turn affected the electrical bias of the applied ion plating process.

Example 3 Several ceramic metal cutting inserts of the SNGA-433 type, consisting of Kyon2000 and Kyon3000, were individually heated in a separate test to about 400 ° C. for about 4 hours, and subsequently continued with Baltour BAI83.
A 1/2 hour ion etch was performed in the 0 system at a pressure of about 10 ^-3 Torr. The first layer of titanium increases the arc current from about 125 amps to about 200 amps in about 2 minutes as the crucible moves vertically into the crucible in the crucible in the vacuum chamber and increases the arc current maintained at 200 amps for about 8 minutes. The surface of the insert was coated by adding. Thereafter, nitrogen gas was introduced into the system for about 80 minutes to form a titanium nitride coating on the insert surface.

The thickness of the titanium nitride coating can be found in the Electrochemical Society of Pennington, New Jersey, 1984, 9th International Conference on CVD, page 757, 9th CVD, incorporated herein by reference.
Determined by the "Thickness test after ball abrasion" specified in PK Mellowtra, DT Kind, and GJ Vuolhue's dissertation. The adhesion level of the coating was determined by the dent test specified in Example 1.
The adhesion level was determined to be equal to or greater than 60 kg. An improved adhesive coating comprising a first layer of titanium and a second layer of titanium nitride adhered and deposited on a ceramic substrate, such as a cutting insert, reduces flank wear and reduces cutting and iron work. It has been found to reduce the coefficient of wear between the piece material. In addition, because titanium nitride is chemically stable, it acts as a barrier to diffusion between the cutting insert and the iron and nickel based work piece materials, thus reducing tool wear problems as described above. It was discovered to be.

Example 4 TNG332 known as K090 under the name K090, consisting of about 73v / o Al ₂ O ₃ and 27v / o TiC
Several ceramic metal cutting inserts of type T are individually heated in a separate test to about 400 ° C. for about 4 hours, followed by 1/2 hour ion etching at a pressure of about 10 ^-3 Torr in a Bartour BAI830 system. Was made. The first layer of titanium is applied to the surface of the insert by applying an arc current of about 125 amps to the titanium in the crucible for about 5 minutes as the crucible rises vertically in the vacuum chamber, after which the crucible is moved vertically to the vacuum chamber. Coating was achieved by applying an arc current of about 200 amps for about 5 minutes when descending in. Nitrogen gas was then introduced into the system for about 80 minutes to form a titanium nitride coating on the insert surface.

Although the thickness of the titanium layer was too thin for optical microscopy measurements, the presence of the titanium layer was observed by transmission electron microscopy. The thickness of the titanium nitride coating is based on 19 Electrochemical Society of Pennington, New Jersey, which is incorporated herein by reference.
1984 9th International Conference Bulletin on CVD, page 757, PK Mellowtra, DT Quint, and
Determined by the "thickness test after ball abrasion" specified in a GJ Vuolhue paper. The thickness of the titanium nitride coating is about 3 on the flank.
It was measured to be microns. The level of adhesion of the coating was determined by the indentation test specified in "Shin Solid Film", No. 154 (1987) pp. 361-375, which is incorporated herein by reference. Using the invention was similar to that of a cemented carbide substrate coated with titanium nitride by physical vapor deposition. The level of adhesion was determined to be equal to or greater than 45 kg for each sample tested.

Example 5 Manufactured in accordance with US Patent Application No. 07 / 266.721,
About 2.5v / o of SiCw, of 10v / o zirconia, magnesia and the remaining 0.5 v / o is, SnGa-433 type several ceramic metal cutting insert with Al ₂ O ₃ is polished to a fine, surface finish And assessed visually by the use of a dye penetrant and washed ultrasonically as described above. The inserts were individually heated in separate tests to a temperature of about 400 ° C. for about 4 hours, followed by a 1/2 hour ion etch in a Bartour BAI830 system at a pressure of about 10 ⁻³ Torr. The first layer of titanium is applied to the surface of the insert, to the titanium in the crucible in the vacuum chamber, by applying an arc current of about 125 amps for about 5 minutes as the crucible rises vertically in the vacuum chamber, and then to the crucible. Was coated by applying an arc current of about 200 amps for about 5 minutes as it descended vertically through the vacuum chamber. Thereafter, nitrogen gas was introduced into the system for about 80 minutes to form a titanium nitride coating on the insert surface.

The thicknesses of the titanium nitride coatings are based on the thicknesses of the Electrochemical Society of Pennington, New Jersey, 1984, 9th International Conference on CVD, 757, incorporated herein by reference.
Page, PK Mellowtra, DT Quint, and GJ Vuolhue determined by the "thickness test after ball wear". The thickness of the titanium nitride coating was measured to be about 2.6 microns on the flank face. Example of coating adhesion level 1
Determined by the dent test specified in This level of adhesion was determined to be equal to or greater than 45 kg for each sample tested.

Example 6 Approximately 5.0 v / o of SiCw, 10 v / o of zirconia, 0.5 v / o of magnesia and the remainder Al ₂ O ₃ in the form of SNGA-433 manufactured according to U.S. patent application Ser. No. 07 / 266.721. Several ceramic metal cutting inserts were polished to a fine surface finish, visually evaluated by the use of a dye penetrant, and ultrasonically cleaned as described above. The insert is then separately heated in a separate test to a temperature of about 400 ° C. for about 4 hours,
After that, about 10 in the Bar Tour BAI830 system
Ion etching was performed at a pressure of ^-3 torr for 1/2 hour. The first layer of titanium is titanium in the crucible. When the crucible rises vertically in the vacuum chamber,
The insert was coated on the surface of the insert by applying an arc current of about 5 amps for about 5 minutes, and then applying an arc current of about 200 amps for about 5 minutes as the crucible descended vertically through the vacuum chamber. Thereafter, nitrogen gas was introduced into the system for about 90 minutes to form a titanium nitride coating on the insert surface.

The thicknesses of the titanium nitride coatings are based on the Electrochemical Society of Pennington, New Jersey, 1984 9th International Conference on CVD 757, CVD, incorporated herein by reference.
Page, PK Mellowtra, DT Quint, and GJ Vuolhue determined by the "thickness test after ball wear". The thickness of the titanium nitride coating was measured to be about 2.6 microns on the flank face. The adhesion level of the coating was determined by the dent test specified in Example 1. The adhesion level was determined to be equal to or greater than 45 kg for each tested sample.

Example 7 About 1.5 v / o of SiCw, 10 v / o of zirconia, 0.5 v / o of magnesia and the remainder are Al ₂ O ₃ in US patent application Ser. No. 07 / 266.721.
Several ceramic metal cutting inserts of the SNGA-433 type manufactured in accordance with the standard are polished to a fine surface finish, visually evaluated by the use of a dye penetrant and then ultrasonically washed as described above. Was done. The inserts were then separately heated in a separate test to a temperature of about 400 ° C. for about 4 hours, followed by a 1/2 hour ion etch at a pressure of about 10 ^-3 Torr in a Bartour BAI830 system. Was done. The first layer of titanium is placed on the titanium in the crucible, about 12 when the crucible rises vertically in the vacuum chamber.
The insert surface was coated by applying an arc current of 5 amps for about 5 minutes, followed by an arc current of about 200 amps for about 5 minutes as the crucible descended vertically through the vacuum chamber. Thereafter, nitrogen gas was introduced into the system for about 90 minutes to form a titanium nitride coating on the insert surface. The thicknesses of the titanium nitride coatings are based on 19 Electrochemical Society, Pennington, New Jersey, which is incorporated herein by reference.
Determined by the "Thickness test after ball wear" specified in the article of the 9th International Conference on CVD in 1984, p. 757, PK Mellowtra, DT Quint, and GJ Vuolhue. The thickness of the titanium nitride coating was measured to be about 2.6 microns on the flank face. The adhesion level of the coating was determined by the dent test specified in Example 1. The adhesion level was determined to be equal to or greater than 45 kg for each tested sample.

The improved adhesive coating includes a first layer of titanium and a second layer of titanium nitride adhered and deposited on a ceramic substrate, such as a cutting insert, to reduce flank wear and to reduce the wear of the cutting insert and iron. It will be appreciated that it has been found to reduce the coefficient of wear between the work piece material. Furthermore, because titanium nitride is chemically stable, it acts as a diffusion barrier between the cutting insert and the iron and nickel based work piece material, thereby reducing the aforementioned tool wear problem. Was found.

The patents and patent applications referred to herein are hereby incorporated by reference.

While the presently preferred embodiments of the invention have been described herein, it should be understood that they can be embodied in other ways within the scope of the appended claims.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Quint Dennis Tay, Pennsylvania, USA 15650 Greensburg Beacon Valerie Road 912 (56) References JP-A-63-45190 (JP, A) JP-A-60-224778 (JP, A) JP-A-60-239365 (JP, A) JP-A-53-102845 (JP, A) JP-A-60-216551 (JP, A) JP-B-63-11425 (JP, B2) 55-38425 (JP, B2)

Claims (8)

(57) [Claims] A method for producing a non-conductive ceramic cutting tool substrate coated by physical vapor deposition, said non-conductive ceramic cutting tool substrate having a source of titanium, partially ionized, Placed in a vacuum chamber filled with an inert gas excited by a gaseous plasma, the substrate of the non-conductive ceramic cutting tool includes a rake surface, a flank surface, and a joint between the rake surface and the flank surface. In the method having a cutting blade at a point, (a) rake and flank surfaces of the substrate of the non-conductive ceramic cutting tool and the cutting blade for at least 3 hours under a vacuum of about 10 ^-3 Torr; Heating to a temperature of 400 ° C, ion etching of the rake surface, the flank surface and the cutting blade, the heating is performed by the impact of high current density electrons, and the non-conductive ceramic substrate A positive potential is placed on the substrate to attract and clean electrons from the gaseous plasma to the rake surface, the flank surface and the cutting blade, and (b) the non-conductive ceramic cutting tool substrate. Depositing a first layer of titanium on the rake face, flank face and cutting blade of (c), depositing a second layer of titanium nitride on the first layer and on the non-conductive ceramic substrate Producing a coating having enhanced adhesion to the coating. 2. A process for the production of a coated non-conductive ceramic cutting tool substrate as defined in claim 1, wherein the rake surface, flank surface and cutting blade of said non-conductive ceramic substrate are subjected to said vacuum. A method characterized in that it is cleaned for at least 4 hours. 3. A method for the production of a coated non-conductive ceramic cutting tool substrate as defined in claim 1, wherein the first layer of titanium is formed on the rake surface, flank surface and cutting edge of the ceramic substrate. A method comprising depositing for about 10 minutes to increase electrical conductivity. 4. A method for the production of a coated non-conductive ceramic cutting tool substrate as defined in claim 1, wherein said physical vapor deposition method is ion plating. 5. A method for producing a coated non-conductive ceramic cutting tool substrate as defined in claim 1, wherein a negative potential is applied to said non-conductive ceramic substrate during said ion etching step. Attracting ions from the gaseous plasma to the rake face, flank face and cutting blade of the non-conductive ceramic substrate. 6. A tool insert coated by physical vapor deposition with an applied electrical bias, comprising: (a) a non-conductive ceramic substrate; and (b) a physical vapor deposited on said ceramic substrate. (C) a second layer of titanium nitride deposited and deposited by physical vapor deposition on the first layer; and (d) the tool insert has a flank face; A tool insert comprising a metal and a cutting insert having a rake surface and a cutting blade at a joint between the flank surface and the rake surface. 7. The tool insert defined in claim 6, wherein the level of adhesion of said titanium nitride layer to said ceramic substrate surface is at least 60 kg in an indentation adhesion test. 8. The tool insert as defined in claim 6, wherein the level of adhesion of said titanium nitride layer to said ceramic substrate surface is at least 45 kg in an indentation adhesion test.