Title of Invention

A CUTTING TOOL/INSERT AND A METHOD OF COATING A CUTTING TOOL

Abstract The present invention relates to ceramic cutting tools, such as, a aluminum oxide with zirconium oxide ceramic cutting tool with diffusion bonding enhanced layer and CVD coatings, particularly useful for machining modem metal materials. The method comprises a chemical reaction with a mixture including nitrogen and aluminum chloride introduced to form a diffusion bonding enhanced layer between the ceramic substrate and the CVD coatings. Thus formed diffusion bonding is highly adherent to the aluminum oxide with zirconium oxide ceramic substrate and significantly enhances the CVD coating properties, and thus improving the machining performance in terms of the tool life of zirconium-based aluminum oxide with zirconium oxide ceramic cutting tools.
Full Text BACKGROUND OF THE INVENTION
At the present time, most cutting inserts comprise substrates made from
cemented carbides because cemented carbides have a high degree of toughness and
good wear resistance. However, the use of cutting tools and cutting inserts ("ceramic
tools") having ceramic substrates is increasing. These ceramic tools find use in a wide
range of high-speed finishing operations and for the machining of difficult-to-machine
materials at a high removal rate. The increase in use of ceramic tools may be due to
improvements in alloyed ceramics and ceramic-matrix composites, as well as with the
advances in ceramic processing technology. The ceramics used in cutting tools are
typically inorganic, nonmetallic materials.
The production of ceramic tools typically involves the consolidation and
sintering of powdered ceramics. Sintering provides the necessary densification of the
consolidated powder and may optionally be performed under pressure. In pressureless
sintering, the powder is first shaped into a green, or unsintered, body which may then be
sintered to achieve the necessary densification. Hot pressing of ceramics involves heating
along with simultaneous uniaxial pressing of the powder in a die. Although hot-pressed
ceramics are more expensive, they may be prepared with a finer grain size, a higher
density and higher transverse rupture strength than cold-pressed materials.
The ceramics currently used in cutting tools are based either on aluminum
oxide (alumina, Al2O3) or silicon nitride (Si3N4). Other ceramics, such as, magnesia, yttria,
zirconia, chromium oxide', and titanium carbide may be used as additives to aid sintering or
to form alloyed ceramics with improved thermo-mechanical properties.
A ceramic tool comprising an aluminum oxide substrate may be used in
metal machining with high cutting speed due to the chemical inertness and great strength
of the aluminum oxide substrate. Commercially significant aluminum oxide ceramic tools
were basically fine grained (less than 5 µm) AI2O3 with magnesia added as a sintering aid
and grain growth inhibitor. Aluminum oxide ceramics may also be alloyed with suboxides
or titanium or chromium to form solid solutions. The three main commercially available
aluminum oxide based tool materials are Al2O3/Ti, AI2O3/Z1-O2, and Al203 reinforced with
silicon carbide (SiC) whiskers. Other Al203 base ceramics may have additives of TiN, TiB2,
Ti(C,N), and Zr(C,N).
Alumina-zirconia (AI2O3/Z1-O2) is an alloyed ceramic. The addition of
zirconium oxide increases the higher fracture toughness and thermal shock resistance of
an aluminum oxide substrate. The toughening of aluminum oxide with zirconium oxide
exploits a specific crystallographic change, a martensitic type transformation, that results
from an energy absorbing mechanism. The presence of metastable tetraorthoganol ZrO2
provides the potential for transformation under stress into a stable monoclinic structure.
The transformation acts as a stress absorber and prevents, even when cracks exist, further
cracking.
Typically, the zirconia oxide particles are concentrated at the aluminum
oxide grain boundaries. Although fracture is intergranular, the presence of these particles
is believed to provide additional toughness before failure can occur by fracture. The three
most popular compositions contain 10, 25, and 40 weight % (wt.%) ZrO2 with the remainder
being aluminum oxide. The 40 wt.% ZrO2 composition is close to the eutectic
concentration. The higher ZrO2 compositions are less hard but tougher.
Cutting inserts may be coated to increase their resistance to wear. Single or
multiple layers of coatings by chemical vapor deposition ("CVD") or physical vapor
deposition ("CVD") may be applied to cutting tool. Titanium nitride (TiN), titanium carbon
nitride (TiCN) and aluminum oxide (AI2O3) are among the most popular CVD coating
materials for carbide-based cutting tools. Thin coatings (2 µm to 5 µm) on ceramic
substrates have been developed primarily to limit chemical interactions between the tool
and the work material and improve wear resistance. Examples of the very recent research
efforts in applying the latest CVD coating technologies to ceramic cutting inserts include
coated reinforced ceramic cutting tools, United States Patent No. 6,447,896; coated silicon
nitride ceramic cutting tools, United States Patent Application No. 2002/0076284; coated
composite ceramic cutting inserts containing a hard phase dispersed with an alumina
matrix phase, Published United States Patent Application No. 2002/0054794.
There is a need to develop new coating technologies for ceramic tools in
order to further improve the wear and chemical resistance of ceramic tools to meet the
ever-increasing demands on machining productivity.
SUMMARY OF THE INVENTION
In at least one aspect, the present invention is directed to cutting tools
comprising a substrate, wherein the substrate comprises aluminum oxide and zirconium
oxide and a diffusion bonding enhanced layer. The present invention is also directed to
methods of forming a diffusion bonding enhanced layer on a substrate. A diffusion bonding
enhanced layer increases the adherence of a wear resistant coating applied to the cutting
tool. The diffusion bonding enhanced layer comprises the reaction products between a
mixture comprising nitrogen and aluminum chloride, and at least the zirconium oxide
present in the substrate.
In another aspect, the present invention is directed to a cutting insert
comprising a substrate, wherein the substrate comprises aluminum oxide and zirconium
oxide, an intermediate layer comprising nitrides of zirconium, zirconium oxide and nitrides
of aluminum, and at least one wear resistant coating.
An embodiment of the method of the present invention comprises exposing
an substrate to aluminum chloride and nitrogen, wherein the substrate comprises alumina
and zirconia; and coating the substrate by at least one of chemical vapor deposition
process or pressure vapor deposition process. The substrate may comprise, by weight,
from 0.5 to 45 % zirconium oxide of the total weight of the substrate. The method may
include exposing the substrate to a gaseous mixture comprising aluminum chloride and
nitrogen.
The coating on the substrate may be applied by CVD or PVD, as well as
other means. Each coating may independently comprise at least one of a metal carbide, a
metal nitride, a metal silicon, and a metal oxide of a metal oxide of a metal selected from
Groups IIIA, IVB, VB, and VIB of the periodic table, such as, but not limited to at least one
of titanium nitride (TiN), titanium carbonitride (TiCN), titanium aluminum nitride (TiAIN),
titanium aluminum nitride plus carbon (TiAIN+C), aluminum titanium nitride (AiTiN),
aluminum titanium nitride plus carbon (AITiN+C), titanium aluminum nitride plus tungsten
carbide/carbon (TiAIN+WC/C), aluminum titanium nitride plus tungsten carbide/carbon
(ATTiN+WC/C), aluminum oxide (Al2O3), titanium diboride (TiB2), tungsten carbide carbon
(WC/C), chromium nitride (CrN) and aluminum chromium nitride (AlCrN).
The reader will appreciate the foregoing details and advantages of the
present invention, as well as others, upon consideration of the following detailed
description of embodiments of the invention. The reader also may comprehend such
additional details and advantages of the present invention upon making and/or using
embodiments within the present invention.
Brief Description Of The Accompanying Drawings(s)
The features and advantages of the present invention may be better
understood by reference to the accompanying figures in which:
Figure 1 is a photomicrograph taken at 1000x magnification of a prepared
cross-section showing the diffusion bonding enhanced layer formed on the surface of the
AI2O3/ZrO2 ceramic substrate;
Figures 2A and 2B are photomicrographs taken at 1000x magnification for
comparison of a CVD coated Al2O3/ZrO2 ceramic substrate without a diffusion bonding
enhanced layer (Figure 2A) and a CVD coated Al2O3/ZrO2 ceramic substrate with a
diffusion bonding enhanced layer (Figure 2B);
Figures 3A and 3B are photomicrographs of Al2O3/ZrO2 ceramic cutting
inserts after scratch tests were performed under a constant load of 10 kg on the CVD
coatings of the two Al2O3/ZrO2 ceramic cutting inserts, one cutting insert was prepared
without a diffusion bonding enhanced layer (Figure 3A) and the other cutting insert was
prepared with diffusion bonding enhanced layer (Figure 3B); and
Figures 4A and 4B are graphs depicting the results of comparative
machining tests (Case 1 and Case 2) that were carried out under different cutting
conditions and with work materials in order to demonstrate the advantages of the ceramic
cutting inserts comprising a substrate of aluminum oxide and zirconium oxide with diffusion
bonding enhanced layer and wear-resistant coatings.
DETAILED DESCRIPTION OF THE PRESENT INVENTION
The present invention relates cutting tools comprising a substrate
comprising aluminum oxide and zirconium oxide, and a diffusion bonding enhanced layer.
The diffusion bonding enhanced layer results from the reaction between reagents and at
least one of the zirconium oxide and aluminum oxide in the substrate. The diffusion
bonding enhanced layer may comprise nitrides of zirconium and nitrides of aluminum and
the presence of these compounds enhances the adhesion of subsequent coatings.
Therefore, the diffusion bonding enhanced layer may be used as an intermediate layer
between the substrate and a wear resistant coating. The presence of a diffusion bonding
enhanced layer may significantly improve the tool life of coated Al203 ceramic cutting
inserts. An embodiment of the present invention results in a chemical reaction between at
least one of the aluminum oxide and the zirconium oxide of the substrate and a mixture of
nitrogen (N2) and aluminum chloride (AICI3) in a surface region. The reaction may be
between a gaseous mixture of N2 and AICI3 and the components of the substrate. Single
or mu.ltiple wear resistant coatings may be applied by a known coating means, including,
but not limited to, CVD and PVD.
The thickness of the diffusion bonded enhanced layer depends on the
diffusion of the reactants into the substrate. Diffusion is the process by which molecules
intermingle as a result of their kinetic energy of random motion, or in other words, it is the
result of random motion of the individual atoms in a surface region of the substrate, i.e. the
aluminum oxide with zirconium oxide ceramic substrate in this invention. At a relatively
high temperature, the rate of diffusion increases and, therefore, certain reactants may be
chemically bonded to a surface region at a certain depth into the substrate. The diffusion
bonding enhanced layer does not intend to function as a wear resistant coating, rather as
an intermediate layer between the ceramic substrate and the refractory metals-based CVD
coatings to increase adherence. Experiments have shown consistently that the direct
application of CVD coatings on the aluminum oxide with zirconium oxide ceramic substrate
often does not result in good adhesion. The coatings typically peel and crack during the
machining process resulting in a short service life of the ceramic tool.
The diffusion bonding enhanced layer provided in this invention may be
relatively uniform, stable and highly adherent layer to the ceramic substrate. It is believed
that the diffusion bonding enhanced layer comprises the products of a reaction between
nitrogen and aluminum chloride, and the zirconium oxide present in the substrate. The
thickness of the diffusion bonding enhanced layer may be controlled by adjusting at least
one of the temperature, pressure, reaction time, surface roughness of the substrate, as
well as other parameters to produce the desired thickness of the coating.
Embodiments of the cutting tool of the present invention comprise a
substrate comprising aluminum oxide and zirconium oxide. Typically, such presently
commercially available substrates comprise, by weight, from 0.5 to 45 % zirconium oxide.
In certain embodiments, such as where a harder substrate may be desired, the substrate
may comprise, by weight, from 0.5 to 26 % zirconium oxide or preferably, from 2 to 26 %
zirconium oxide, or more preferably from 9 to 11 % zirconium oxide.
Embodiments of the cutting tool may comprise single or multiple wear
resistant or chemical resistant coatings, together referred to herein as "wear resistant
coatings." The single or multiple wear resistant coatings on a diffusion enhanced bonding
layer as a bonding interface intermediate the first wear resistant coating and coatings and
the substrate, results in enhanced adhesive performance of coating and the aluminum
oxide with zirconium oxide ceramic substrate is enhanced. The cutting tool may comprise
any coating capable of being deposited by CVD or PVD. More particularly, the wear
resistant coatings may independently comprise at least one of a metal carbide, a metal
nitride, a metal carbonitride, a metal silicon and a metal oxide of a metal selected from
groups II1A, IVB, VB, and V1B of the periodic table or combination thereof, such as, but not
limited to, titanium nitride (TiN), titanium carbonitride (TiCN), titanium aluminum nitride
(TiAIN), titanium aluminum nitride plus carbon (TiAIN+C), aluminum titanium nitride (AITiN),
aluminum titanium nitride plus carbon (AITiN+C), titanium aluminum nitride plus tungsten
carbide/carbon (TiAIN+WC/C), aluminum titanium nitride plus tungsten carbide/carbon
(AITiN+WC/C), aluminum oxide (Al203), titanium diboride (TiB2), tungsten carbide carbon
(WC/C), chromium nitride (CrN) and aluminum chromium nitride (AlCrN). A typical
commercial multilayer coating for a cutting tool may comprise, for example, a first wear
resistant coating of titanium nitride, a second wear resistant coating of titanium
carbonitride, and the third wear resistant coating of titanium nitride.
The thickness of each wear resistant coating may be any thickness desired
for the specific machining application or the material to be machined. The total thickness
of the coating on the surface of the substrate will typically be from about 1 to about 20
micrometers or more typically from 1 to 5 micrometers. Individual wear resistant coatings,
typically, may have a thickness of from 0.25 to 2 micrometers.
Embodiments of the cutting tools of the invention may also comprise a
substrate, wherein the substrate comprises aluminum oxide and zirconium oxide, an
intermediate layer comprising nitrides of zirconium, zirconium oxide and nitrides of
aluminum, and at least one wear resistant coating.
The present invention also relates to a method of coating a cutting tool.
Embodiments of the method comprise exposing an substrate to aluminum chloride and
nitrogen, wherein the substrate comprises aluminum oxide and zirconium oxide, and
coating the substrate by at least one process selected from CVD and PVD. Embodiments
of the method of the present invention include a substrate comprising, by weight, from 0.5
to 45 % zirconium oxide. In certain embodiments where a harder substrate may be
desired, the substrate comprises, by weight, from 0.5 to 26 % zirconium oxide or
preferably, by weight, from 2 to 26 % zirconium oxide, or more preferably, by weight, from
9 to 11 % zirconium oxide.
The substrate may be exposed to a gaseous mixture comprising aluminum
chloride and nitrogen. The gaseous mixture may comprise an aluminum chloride
concentration from 25% to 99% by weight or more preferably, from 75% to 99% by weight.
The gaseous mixture may contain other components that are inert or essentially inert, by
"essentially inert" is meant that the additional components do not interfere with formation of
a diffusion bonding enhanced layer. When a gaseous mixture comprising aluminum
chloride and nitrogen is used to form the diffusion bonding enhanced layer any pressure
may be used although higher pressures will allow more interaction between the gaseous
phase and the solid phase. The pressure of gaseous mixture used in the diffusion process
may be used to control the reaction for forming the diffusion enhanced layer. A higher
pressure may promote a higher level of reactivity between the zirconium oxide and
nitrogen. Therefore, to provide the appropriate control, it may be preferable to maintain a
pressure from 200 millibar to 1500 millibar or even a pressure from 400 millibar to 1000
millibar.
Diffusion may occur in a solid at any temperature. Either the gaseous
mixture or the substrate may be heated to increase the rate of diffusion. Higher
temperatures may result in a higher rate of diffusion but the operating temperatures should
not be so high as to cause any undesired changes in the solid substrate. Therefore, for
substrates comprising aluminum oxide and zirconium oxide, it may be preferred that the
gaseous mixture or the substrate is at a temperature from 50°C to 1400°C or from 50°C to
1200"C. More narrow temperature ranges may be desired to maintain a commercially
acceptable rate of diffusion and not affect the substrate, therefore, it may be desired to
have a temperature of the gaseous mixture or the substrate from 500°C to 1200°C or more
preferably from 10008C to 1200°C.
Unless otherwise indicated, all numbers expressing quantities of
ingredients, time, temperatures, and so forth used in the present specification and claims
are to be understood as being modified in all instances by the term "about." Accordingly,
unless indicated to the contrary, the numerical parameters set forth in the following
specification and claims are approximations that may vary depending upon the desired
properties sought to be obtained by the present invention. At the very least, and not as an
attempt to limit the application of the doctrine of equivalents to the scope of the claims,
each numerical parameter should at least be construed in light of the number of reported
significant digits and by applying ordinary rounding techniques.
Notwithstanding that the numerical ranges and parameters setting forth the
broad scope of the invention are approximations, the numerical values set forth in the
specific examples are reported as precisely as possible. Any numerical value, however,
may inherently contain certain errors necessarily resulting from the standard deviation
found in their respective testing measurements.
EXAMPLES OF EMBODIMENTS OF THE INVENTION
The following examples demonstrate the formation of diffusion bonding
enhanced layer on the substrate comprising aluminum oxide and zirconium oxide and the
increased adherence of the wear resistant coatings on the substrate. The ceramic
substrate of this example comprised in weight percentage, 90% Al203 and 10% ZrO2. The
substrate had a density of 4.0 g/cm3, a hardness of 1800 Hv, a toughness of 4.5 MN/m3/2,
and a heat transfer coefficient of 0.07 cal/cm.sec °C.
The substrate was exposed to a gaseous mixture comprising aluminum
chloride and nitrogen under a pressure of 500 millibar. The substrate was heated to a
temperature of approximately 1020°C. The ratio of AICI3/N2 in the gaseous mixture was
approximately 7.
Figure 1 is a photomicrograph taken at 1000X magnification of a prepared
cross-section of a cutting tool 10 of the present invention at a perspective view showing the
edge 11 between the top 12 and the cross-sectional face 13. The diffusion bonding
enhanced layer 14 is clearly shown on the substrate 15 after exposure to the gaseous
mixture. As may be seen in Figure 1, the diffusion bonding enhanced layer 14 is formed
evenly across the surface of the substrate 15. The thickness of the diffusion-bonding layer
14 on the substrate 15 of Figure 1 is about half micrometer (0.5 micrometer).
Figure 2A and 2B are photomicrographs taken at a magnification of 1000X
of cross-sections of coated Al2O3/ZrO2 ceramic substrate on which multiple wear resistant
coatings were applied. Figure 2A shows a photomicrograph of a cross-section of a coated
ceramic substrate 20 having a first coating of TiN 22, a second coating of TiCN 23, and a
third coating of TiN 24 applied directly on the substrate 21 without an intermediate diffusion
bonding enhanced layer. Figure 2B shows a photomicrograph of a cross-section of a
coated ceramic substrate 25 with a diffusion bonding enhanced layer 30 between the first
coating of TIN 27 coating and the substrate 26. The coated ceramic substrate 25 also has
a second coating of TiCN 28 and a third coating of TiN 29. As may be seen in Figure 2A,
the first coating of TiN 22 neither adheres well nor distributes uniformly across the
AlsO3/ZrO2 ceramic substrate 21, the poor adherence may be evidenced by the dark areas
31 of the photomicrograph between the first coating of TiN 22 and the substrate 21. In
contrast, the diffusion bonding enhanced layer 30 has good adherence and uniform
distribution on both the first coating of TiN 27 and the substrate 26. The multiple coatings
shown in both substrates 20 and 25 of Figures 2A and 2B are TiN-TiCN-TiN all deposited
by CVD with a total thickness of 3 micrometers The diffusion bonding enhanced layer
formed on the base Al203/ZrO2 ceramic substrate 26 may be composed of various
chemical elements or compounds, including zirconium nitride, zirconium oxide, and
aluminum nitride, that are melted together in a fashion to produce a uniform distribution of
the mixed metals.
TESTING OF COATED CUTTING TOOLS
Scratch Test
Performance tests were conducted to determine whether a cutting tool
comprising a diffusion bonding enhanced layer intermediate to the substrate and the first
wear resistant coating would provide a strong adherence for the CVD or PVD coatings
(single or multiple layers). Two cutting tools were prepared one with a multiple wear
resistant coatings applied directly to the substrate and a second with a diffusion enhanced
bonding layer intermediate to the substrate and the multiple wear resistant coatings formed
by the method described above. Both cutting inserts were similarly coated with TiN-TiCN-
TiN with three micrometers in thickness by CVD. Figure 3A and Figure 3B are
photographs of each of the coated ceramic substrates after scratch tests were performed
under a constant load of 10 kg. The cutting insert 40 of Figure 3A does not comprise a
diffusion bonding enhanced layer and the cutting insert 50 of Figure 3B does comprise the
diffusion bonding enhanced layer. As shown in Figure 3A, the CVD coatings 41 have
peeled and chipped along the scratch mark 42 and the white ceramic surface 43 is
exposed under the scratch pressure applied. In fact, the weak adhesion of the CVD
coatings without a diffusion bonding enhanced bonding layer is also indicated by
comparing the width scratch mark 42 in Figure 3A with the narrow scratch mark 52 in
Figure 3B. The formation of a wider scratch 42 in Figure 3A is because the wear resistant
coatings 41 has a low resistance to chipping and peeling from the scratch load applied
during the test (same 10-kg constant pressure for both cases). While the formation of the
narrow scratch mark 52 in Figure 3B is a result of the strong adherence of the CVD
coatings 51 to the diffusion bonding enhanced layer between the Al2O3/ZrO2 ceramic
substrate and the CVD coatings applied. The scratch test clearly indicates that the
diffusion bonding enhanced layer improves adherence of the CVD coatings on the
Al2O3/ZrO2 ceramic substrate.
Machining Tests
A series of comparative machining tests was carried out under various
cutting conditions and with various work materials to demonstrate the advantages of a
cutting tool comprising an intermediate diffusion bonding enhanced layer and multiple wear
resistant coatings.
Case 1: Machining of the Iron Material for Automotive Parts
Three Al2O3/ZrO2 ceramic cutting tools were selected for the comparative
machining test - as shown in Table 1. All the cutting inserts have the same style and
geometry, designated as SNEN120412, which denotes a square shape with an inscribed
diameter of 12mm, a thickness of 4.76 mm, and a corner nose radius of 1.20 mm
according to the ISO standard. The cutting inserts of Case 1 have a single T-Land around
the cutting edges.

The machining tests of Case 1 were performed under the following cutting
conditions:
Cutting speed = 1600 feet per minute (480 meters per minute)
Feed rate = 0.01 inch per revolution (0.25 mm per revolution)
Depth of cut = 0.020 inch (0.5 mm)
Insert designated C1B was coated directly on the substrate while insert
designated C1C was coated accordingly to the method of the present invention, as
described above. The test results are shown in Figure 4A. It is clear that the cutting insert
C1C (TiN-TiCN-TiN CVD coated) with the diffusion bonding enhanced layer demonstrated
the best performance. The diffusion bonding enhanced layer resulted in more than 80%
increase in tool life compared with the cutting insert C1B (TiN CVD coated), and a nearly
200% increase comparing with the uncoated cutting insert C1C.
Case 2: Machining of the Alloy Steels
Three Al2O3/ZrO2 ceramic cutting tools were selected for the comparative
machining test, as shown in Table 2. All the cutting inserts have the same style and
geometry, designated as RCGX251200, which denotes a round shape with a diameter of
25 mm, a side clearance angle of 7 degrees, and a thickness of 12.7 mm, according to the
ISO standard. The cutting inserts of Case 2 were prepared with double T-Lands around
the cutting edges.

The machining tests of Case 2 were performed under the following test
conditions:
Cutting speed = 1000 feet per minute (305 meters per minute)
Feed rate = 0.03 - 0.055 inch per revolution (0.76 - 1.40 mm per revolution)
Depth of cut = 0.027 - 0.055 inch (0.69 -1.40 mm)
The machining test results of Case 2 are shown in Figure 4B. It indicates
clearly that both the cutting insert C2B with TiN CVD coating and the cutting insert C2C
with TiN-TiCN-TiN CVD coating demonstrate better performance in terms of tool life than
the cutting insert C2A with TiN CVD coating of the prior art.
It is to be understood that the present description illustrates those aspects of
the invention relevant to a clear understanding of the invention. Certain aspects of the
invention that would be apparent to those of ordinary skill in the art and that, therefore,
would not facilitate a better understanding of the invention have not been presented in
order to simplify the present description. Although embodiments of the present invention
have been described, one of ordinary skill in the art will, upon considering the foregoing
description, recognize that many modifications and variations of the invention may be
employed. All such variations and modifications of the invention are intended to be
covered by the foregoing description and the following claims.
WE CLAIM:
1. A cutting tool, comprising:
a substrate, wherein the substrate comprises aluminum oxide and zirconium oxide;
and
a diffusion bonding enhanced layer, wherein the diffusion bonding enhanced layer
comprises the reaction products between a gaseous mixture comprising nitrogen and
aluminum chloride, and the zirconium oxide.
2. The cutting tool as claimed in claim 1, comprising:
a wear resistant coating.
3. The cutting tool as claimed in claim 1, wherein the thickness of the diffusion
bonding enhanced layer ranges from 0.25 to 2.0 micrometers.
4. The cutting tool as claimed in claim 1, wherein the diffusion bonding enhanced layer
comprises at least one of zirconium oxide, nitrides of zirconium, and nitrides of aluminum.
5. The cutting tool as claimed in claim 1, wherein the substrate comprises, by weight,
from 0.5 to 45% zirconium oxide.
6. The cutting tool as claimed in claim 5, wherein the substrate comprises, by weight,
from 0.5 to 26% zirconium oxide.
7. The cutting tool as claimed in claim 6, wherein the substrate comprises, by weight,
from 2 to 26% zirconium oxide.
8. The cutting tool as claimed in claim 7, wherein the substrate comprises, by weight,
from 9 to 11 % zirconium oxide.
9. The cutting tool as claimed in claim 1, wherein the substrate comprises, by weight,
from 0.3 to 35% zirconium.
10. The cutting tool as claimed in claim 9, wherein the substrate comprises, by weight,
from 6 to 20%.
11. The cutting tool as claimed in claim 2, wherein the coating comprises at least one of
a metal carbide, a metal nitride, a metal silicon and a metal oxide of a metal selected from
groups IIIA, IVB, VB, and VIB of the periodic table.
12. The cutting tool as claimed in claim 11, wherein the coating comprises at least one of
titanium nitride (TiN), titanium carbonitride (TiCN), titanium aluminum nitride (TiAIN),
titanium aluminum nitride plus carbon (TiAlN+C), aluminum titanium nitride (AlTiN),
aluminum titanium nitride plus carbon (AlTiN+C), titanium aluminum nitride plus tungsten
carbide/carbon (TiAlN+WC/C), aluminum titanium nitride plus tungsten carbide/carbon
(AlTiN+WC/C), aluminum oxide (Al2O3), titanium diboride (TiB2), tungsten carbide carbon
(WC/C), chromium nitride (CrN) and aluminum chromium nitride (AlCrN).
13. The cutting tool as claimed in claim 2, comprising a second coating.
14. The cutting tool as claimed in claim 13, wherein the second coating comprises at
least one of a metal carbide, a metal nitride, a metal silicon and a metal oxide of a metal
selected from groups IIIA, IVB, VB, and VIB of the periodic table.
15. The cutting tool as claimed in claim 14, wherein the second coating comprises at
least one of titanium nitride (TiN), titanium carbonitride (TiCN), titanium aluminum nitride
(TiAIN), titanium aluminum nitride plus carbon (TiAlN+C), aluminum titanium nitride
(AlTiN), aluminum titanium nitride plus carbon (AlTiN+C), titanium aluminum nitride plus
tungsten carbide/carbon (TiAlN+WC/C), aluminum titanium nitride plus tungsten carbide/
carbon (AlTiN+WC/C), aluminum oxide (Ab03), titanium diboride (TiB2), tungsten carbide
carbon (WC/C), chromium nitride (CrN) and aluminum chromium nitride (AlCrN).
16. The cutting tool as claimed in claim 11, wherein the coating has a thickness from 1
to 30 micrometers.
17. The cutting tool as claimed in claim 14, wherein the second coating has a thickness
from 1 to 20 micrometers.
18. A cutting insert, comprising:
a substrate, wherein the substrate comprises aluminum oxide and zirconium oxide;
an intermediate layer comprising nitrides of zirconium, zirconium oxide and nitrides
of aluminum; and
a first wear resistant coating.
19. The cutting insert as claimed in claim 18, comprising:
a second wear resistant coating.
20. The cutting insert as claimed in claim 19, wherein the thickness of the first wear
resistant coating and the second wear resistant coating together is between 1 and 20
micrometers.
21. The cutting insert as claimed in claim 20, wherein the first wear coating and the
second wear resistant coating independently comprise at least one of a metal carbide, a
metal nitride, a metal silicon and a metal oxide of a metal selected from groups IIIA, IVB,
VB, and VIB of the periodic table.
22. The cutting insert as claimed in claim 21, wherein the first wear resistant coating and
the second wear resistant coating independently comprise at least one of titanium nitride
(TiN), titanium carbonitride (TiCN), titanium aluminum nitride (TiAN), titanium aluminum
nitride plus carbon (TiAIN+C), aluminum titanium nitride (AlTiN), aluminum titanium
nitride plus carbon (AlTiN+C), titanium aluminum nitride plus tungsten carbide/carbon
(TiAlN+WC/C), aluminum titanium nitride plus tungsten carbide/carbon (AlTiN+WC/C),
aluminum oxide (A12O3) , titanium diboride (TiB2), tungsten carbide carbon (WC/C),
chromium nitride (CrN) and aluminum chromium nitride (AlCrN).
23. The cutting insert as claimed in claim 20, comprising a third wear resistant coating.
24. The cutting insert as claimed in claim 23, wherein the third wear resistant coating
comprises at least one of a metal carbide, a metal nitride, a metal silicon and a metal oxide
of a metal selected from groups IHA, IVB, VB, and VIB of the periodic table.
25. The cutting insert as claimed in claim 25, wherein the third wear resistant coating
comprises at least one of titanium nitride (TiN), titanium carbonitride (TiCN), titanium
aluminum nitride (TiAIN), titanium aluminum nitride plus carbon (TiAIN+C), aluminum
titanium nitride (AlTiN), aluminum titanium nitride plus carbon (AlTiN+C), titanium
aluminum nitride plus tungsten carbide/carbon (TiAlN+WC/C), aluminum titanium nitride
plus tungsten carbide/carbon (AlTiN+WC/C), aluminum oxide (Al203) , titanium diboride
(TiB2), tungsten carbide carbon (WC/C), chromium nitride (CrN) and aluminum chromium
nitride (AlCrN).
26. The cutting insert as claimed in claim 23, wherein the first wear resistant coating
comprises titanium nitride, the second wear resistant coating comprises titanium
carbonitride, and the third wear resistant coating comprises titanium nitride.
27. The cutting insert as claimed in claim 26, wherein the intermediate layer has a
thickness of from 0.25 to 2 micrometers.
28. The cutting insert as claimed in claim 27, wherein at least one of the first wear
resistant coating, second wear resistant coating, and the third wear resistant coating were
applied by chemical vapor deposition.
29. The cutting insert as claimed in claim 28, wherein the concentration of zirconium
oxide is from 0.5 to 45% by weight.
30. A method of coating a cutting tool, comprising:
exposing an substrate to aluminum chloride and nitrogen, wherein the substrate
comprises alumina and zirconia; and
coating the substrate with a first coating by at least one of chemical vapor deposition
process or physical vapor deposition process.
31. The method as claimed in claim 30, wherein the substrate comprises, by weight,
from 0.5 to 45% zirconium oxide.
32. The method as claimed in claim 31, wherein the substrate comprises, by weight,
from 0.5 to 26% zirconium oxide.
33. The method as claimed in claim 32, wherein the substrate comprises, by weight,
from 2 to 26% zirconium oxide.
34. The method as claimed in claim 33, wherein the substrate comprises, by weight,
from 0.5 to 11% zirconium oxide.
35. The method as claimed in claim 34, wherein the substrate comprises, by weight,
from 9 to 11% zirconium oxide.
36. The method as claimed in claim 31, wherein the exposing the substrate to aluminum
chloride and nitrogen comprises exposing the substrate to a gaseous mixture comprising
aluminum chloride and nitrogen.
37. The method as claimed in claim 36, wherein the gaseous mixture is under a pressure
from 200 millibar to 1500 millibar.
38. The method as claimed in claim 37, wherein the gaseous mixture is under a pressure
from 500 15 millibar to 1000 millibar.
39. The method as claimed in claim 31, wherein the gaseous mixture is at a temperature
from 50°C to 1400°C.
40. The method as claimed in claim 39, wherein the gaseous mixture is at a temperature
from 50°C to 1200°C.
41. The method as claimed in claim 40, wherein the gaseous mixture is at a temperature
from 500°C to 1200°C.
42. The method as claimed in claim 41, wherein the gaseous mixture is at a temperature
from 1000°C to 1200°C.
43. The method as claimed in claim 42, wherein the gaseous mixture comprises
aluminum chloride concentration from 25% to 99% by weight.
44. The method as claimed in claim 43, wherein the gaseous mixture comprises
aluminum chloride concentration from 75% to 99% by weight
45. The method as claimed in claim 30, wherein the coating the substrate by at least one
of chemical vapor deposition process and a physical vapor deposition process results in a
coating comprising at least one of a metal carbide, a metal nitride, a metal silicon, and a
metal oxide of a metal oxide of a metal selected from Groups IUA, IVB, VB, and VTB of the
periodic table.
46. The method as claimed in claim 45, wherein the coating comprises at least one of
titanium nitride (TiN), titanium carbonitride (TiCN), titanium aluminum nitride (TiAIN),
titanium aluminum nitride plus carbon (TiAlN+C), aluminum titanium nitride (AlTiN),
aluminum titanium nitride plus carbon (AlTiN+C), titanium aluminum nitride plus tungsten
carbide/carbon (TiAIN+WC/C), aluminum titanium nitride plus tungsten carbide/carbon
(AlTiN+WC/C), aluminum oxide (A1203), titanium diboride (TiB2), tungsten carbide carbon
(WC/C), chromium nitride (CrN) and aluminum chromium nitride (AlCrN).
47. The method as claimed in claim 30 comprises:
coating the substrate with a second coating by one of a physical vapor deposition
process and a chemical vapor deposition process.
48. The method as claimed in claim 47, wherein the coating the substrate with a second
coating results in a second coating comprising at least one of a metal carbide, a metal
nitride, a metal silicon, and a metal oxide of a metal oxide of a metal selected from Groups
mA, IVB, VB, and VIB of the periodic table.
49. The method as claimed in claim 49, wherein the second coating comprises at least
one of titanium nitride (TiN), titanium carbonitride (TiCN), titanium aluminum nitride
(TiAIN), titanium aluminum nitride plus carbon (TiAIN+C), aluminum titanium nitride
(AlTiN), aluminum titanium nitride plus carbon (AlTiN+C), titanium aluminum nitride plus
tungsten carbide/carbon (TiAIN+WC/C), aluminum titanium nitride plus tungsten carbide/
carbon (AlTiN+WC/C), aluminum oxide (Al2O3), titanium diboride (TiB2), tungsten carbide
carbon (WC/C), chromium nitride (CrN) and aluminum chromium nitride (AlCrN).
50. The method as claimed in claim 47, wherein the first coating has a thickness from
0.25 to 20 micrometers.
51. The method as claimed in claim 50, wherein the first coating has a thickness from
0.25 to 5.0 micrometers.
52. The method as claimed in claim 48, wherein the total coating has a thickness from 1
to 20 micrometers.


The present invention relates to ceramic cutting tools, such as, a aluminum oxide with
zirconium oxide ceramic cutting tool with diffusion bonding enhanced layer and CVD
coatings, particularly useful for machining modem metal materials. The method comprises a
chemical reaction with a mixture including nitrogen and aluminum chloride introduced to
form a diffusion bonding enhanced layer between the ceramic substrate and the CVD
coatings. Thus formed diffusion bonding is highly adherent to the aluminum oxide with
zirconium oxide ceramic substrate and significantly enhances the CVD coating properties,
and thus improving the machining performance in terms of the tool life of zirconium-based
aluminum oxide with zirconium oxide ceramic cutting tools.

Documents:

03274-kolnp-2006 abstract.pdf

03274-kolnp-2006 assignment.pdf

03274-kolnp-2006 claims.pdf

03274-kolnp-2006 correspondence others.pdf

03274-kolnp-2006 description(complete).pdf

03274-kolnp-2006 drawings.pdf

03274-kolnp-2006 form-1.pdf

03274-kolnp-2006 form-3.pdf

03274-kolnp-2006 form-5.pdf

03274-kolnp-2006 international publication.pdf

03274-kolnp-2006 internationalsearch authority.pdf

03274-kolnp-2006 pct other.pdf

03274-kolnp-2006-assignment-1.1.pdf

03274-kolnp-2006-correspondence-1.1.pdf

3274-KOLNP-2006-ABSTRACT 1.1.pdf

3274-KOLNP-2006-ASSIGNMENT.pdf

3274-KOLNP-2006-CLAIMS 1.1.pdf

3274-KOLNP-2006-CORRESPONDENCE 1.1.pdf

3274-KOLNP-2006-CORRESPONDENCE 1.2.pdf

3274-KOLNP-2006-CORRESPONDENCE 1.3.pdf

3274-KOLNP-2006-CORRESPONDENCE 1.4.pdf

3274-KOLNP-2006-CORRESPONDENCE 1.5.pdf

3274-KOLNP-2006-CORRESPONDENCE.pdf

3274-KOLNP-2006-DESCRIPTION (COMPLETE) 1.1.pdf

3274-KOLNP-2006-DRAWINGS 1.1.pdf

3274-KOLNP-2006-EXAMINATION REPORT REPLY RECIEVED.pdf

3274-KOLNP-2006-EXAMINATION REPORT.pdf

3274-KOLNP-2006-FORM 1 1.1.pdf

3274-KOLNP-2006-FORM 18 1.1.pdf

3274-kolnp-2006-form 18.pdf

3274-KOLNP-2006-FORM 2.pdf

3274-KOLNP-2006-FORM 3 1.1.pdf

3274-KOLNP-2006-FORM 3.pdf

3274-KOLNP-2006-FORM 5.pdf

3274-KOLNP-2006-FORM-27.pdf

3274-KOLNP-2006-GPA.pdf

3274-KOLNP-2006-GRANTED-ABSTRACT.pdf

3274-KOLNP-2006-GRANTED-CLAIMS.pdf

3274-KOLNP-2006-GRANTED-DESCRIPTION (COMPLETE).pdf

3274-KOLNP-2006-GRANTED-DRAWINGS.pdf

3274-KOLNP-2006-GRANTED-FORM 1.pdf

3274-KOLNP-2006-GRANTED-FORM 2.pdf

3274-KOLNP-2006-GRANTED-SPECIFICATION.pdf

3274-KOLNP-2006-OTHER DOCUMENT 1.1.PDF

3274-KOLNP-2006-OTHER DOCUMENT.PDF

3274-KOLNP-2006-OTHERS 1.1.pdf

3274-KOLNP-2006-OTHERS.pdf

3274-KOLNP-2006-PETITION UNDER RULE 137.pdf

3274-KOLNP-2006-PRIORITY DOCUMENT.pdf

3274-KOLNP-2006-REPLY TO EXAMINATION REPORT 1.1.pdf

abstract-03274-kolnp-2006.jpg


Patent Number 250466
Indian Patent Application Number 3274/KOLNP/2006
PG Journal Number 02/2012
Publication Date 13-Jan-2012
Grant Date 04-Jan-2012
Date of Filing 08-Nov-2006
Name of Patentee TDY INDUSTRIES, INC.
Applicant Address 1000 SIX PPG PLACE, PITTSBURGH, PA 15222
Inventors:
# Inventor's Name Inventor's Address
1 FANG ,X., DANIEL 509 HODGES COURT, FRANKLIN, TN 37067
2 FESTEAU , GILLES 456 ESSEX PARK CIRCLE , FRANKLIN , TN 37069
3 WILLS ,DAVID , J. 9051 FALLSWOOD LANE , BRENTWOOD , TN 37027
PCT International Classification Number C23C 12/00,B32B9/00;
PCT International Application Number PCT/US2005/015720
PCT International Filing date 2005-05-05
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10/848,776 2004-05-19 U.S.A.