U.S. patent application number 10/902381 was filed with the patent office on 2006-02-02 for mullite-aluminum titanate body and method for making same.
Invention is credited to Gregory A. Merkel.
Application Number | 20060021308 10/902381 |
Document ID | / |
Family ID | 35730576 |
Filed Date | 2006-02-02 |
United States Patent
Application |
20060021308 |
Kind Code |
A1 |
Merkel; Gregory A. |
February 2, 2006 |
Mullite-aluminum titanate body and method for making same
Abstract
This invention relates to a mullite-aluminum titanate body
having a low coefficient of thermal expansion of less than
15.times.10.sup.-7 C.sup.-1, a high porosity of at least 38% by
volume, a median pore diameter of at least 8 microns, and a narrow
pore size distribution as characterized by the relation
(d.sub.50-d.sub.10)/d.sub.50 being less than 0.50 corresponding to
a high degree of interconnected porosity. The inventive ceramic
body also contains at least 0.10% by weight metal oxide, the metal
being either yttrium, calcium, bismuth, a lanthanide metal or
combinations of thereof. The inventive ceramic body is particularly
useful as a wall-flow filter for diesel exhaust. A method of
fabrication is provided where the sintering temperature is between
1375.degree.-1550.degree. C.
Inventors: |
Merkel; Gregory A.; (Painted
Post, NY) |
Correspondence
Address: |
CORNING INCORPORATED
SP-TI-3-1
CORNING
NY
14831
US
|
Family ID: |
35730576 |
Appl. No.: |
10/902381 |
Filed: |
July 29, 2004 |
Current U.S.
Class: |
55/523 |
Current CPC
Class: |
C04B 2235/3454 20130101;
B01D 46/2444 20130101; F01N 2330/06 20130101; C04B 2235/3217
20130101; C04B 2235/3293 20130101; C04B 2235/3298 20130101; C04B
2235/3258 20130101; C04B 2235/3208 20130101; C04B 2235/322
20130101; C04B 2235/3227 20130101; Y02T 10/20 20130101; C04B
2235/3213 20130101; F01N 2330/14 20130101; C04B 35/478 20130101;
C04B 2235/445 20130101; Y10S 55/30 20130101; C04B 2235/3205
20130101; C04B 2235/9607 20130101; C04B 2235/3232 20130101; B01D
2046/2496 20130101; C04B 35/6263 20130101; C04B 2235/3222 20130101;
C04B 2235/3225 20130101; C04B 2235/5445 20130101; C04B 2235/3409
20130101; C04B 2235/3463 20130101; Y10S 55/10 20130101; C04B
2235/3218 20130101; F01N 3/022 20130101; C04B 2235/77 20130101;
C04B 2111/00129 20130101; C04B 2235/80 20130101; Y02T 10/12
20130101; B01D 46/2429 20130101; C04B 35/185 20130101; C04B
2235/3251 20130101; C04B 2235/96 20130101; B01D 46/244 20130101;
C04B 2235/5436 20130101; C04B 2235/3236 20130101; C04B 2235/3244
20130101; C04B 2235/3229 20130101; C04B 2235/3284 20130101; C04B
2235/3418 20130101; C04B 2235/3256 20130101; C04B 2235/6567
20130101; B01D 2046/2433 20130101; C04B 2235/3224 20130101; C04B
2235/3231 20130101; C04B 2235/3286 20130101; B01D 2279/30 20130101;
Y10S 55/05 20130101; B01D 2046/2437 20130101; C04B 35/632 20130101;
C04B 2111/00793 20130101; Y10S 264/48 20130101; C04B 38/0006
20130101; C04B 2235/349 20130101; C04B 2235/656 20130101; C04B
38/0006 20130101; C04B 35/185 20130101; C04B 35/478 20130101; C04B
38/0074 20130101; C04B 38/0006 20130101; C04B 35/185 20130101; C04B
35/478 20130101; C04B 38/0009 20130101; C04B 38/0051 20130101; C04B
38/0054 20130101; C04B 38/0074 20130101 |
Class at
Publication: |
055/523 |
International
Class: |
B01D 46/00 20060101
B01D046/00 |
Claims
1. A ceramic body comprising phase of mullite and aluminum
titanate, and at least 0.10% by weight of a metal oxide for a metal
selected from the group consisting of bismuth, calcium, yttrium,
lanthanides and combinations thereof, while exhibiting a set of
properties including a coefficient of thermal expansion
(RT-1000.degree. C.) less than 15.times.10.sup.-7 C.sup.-1, a
porosity of at least 38% by volume, a median pore diameter of at
least 8 microns, and a narrow pore size distribution as
characterized by the relation (d.sub.50-d.sub.10)/d.sub.50 being
less than 0.50 corresponding to a high degree of interconnected
porosity.
2. The ceramic body of claim 1 wherein the metal oxide is in an
amount of between 0.10% to 5.0% by weight.
3. The ceramic body of claim 2 wherein the metal is yttrium.
4. The ceramic body of claim 1 wherein the ceramic body exhibits
said set of properties when sintered to a temperature of between
1375.degree. C. to 1550.degree. C.
5. A diesel exhaust particulate filter comprising the ceramic body
of claim 1, wherein the ceramic body is a plugged, wall-flow
honeycomb body having a plurality of parallel end-plugged cell
channels traversing the body from a frontal inlet end to an outlet
end thereof.
6. The diesel exhaust particulate filter of claim 5 further
exhibiting a coefficient of thermal expansion (RT-1000.degree. C.)
not greater than 10.times.10.sup.-7 C.sup.-1, a porosity of between
45-60% by volume, a median pore diameter of between 10-20 microns,
and a narrow pore size distribution as characterized by the
relation (d.sub.50-d.sub.10)/d.sub.50 being not greater than 0.35
corresponding to a high degree of interconnected porosity.
7. A method for making a mullite-aluminum titanate ceramic body
comprising: a. providing a mixture of inorganic raw materials
comprising an alumina source, a silica source, and a titanium
dioxide source, in combination with a source of a metal oxide as a
sintering additive in an amount of at least 0.10% by weight
super-addition, the source corresponding to an oxide of a metal
selected from the group of metals consisting of bismuth, calcium,
yttrium, lanthanides and combinations thereof, b. shaping the
mixture into a body; and, c. sintering the body to a temperature of
between 1375.degree. C. to 1550.degree. C. for a period of between
1 hour to 15 hours; wherein the weighted average of the median
particle diameters of the inorganic raw materials, D.sub.50, is at
least 6 microns to form a pore size in the mullite-aluminum
titanate ceramic body after sintering of at least 8 microns.
8. The method of claim 7 wherein the metal oxide is added to the
raw material mixture in an amount between 0.10% and 5.0% by
weight.
9. The method of claim 8 wherein the metal is yttrium.
10. The method of claim 7 wherein an amount of at least 0.05% by
weight of molybdenum oxide or tungsten oxide is further added to
the mixture.
11. The method of claim 7 wherein the alumina source is a selected
from a group consisting of corundum, gamma-alumina or another
transitional alumina, boehmite, alumina hydroxide (gibbsite) and
mixtures thereof.
12. The method of claim 11 wherein the alumina source has a median
particle diameter greater than 15 microns.
13. The method of claim 7 wherein the mixture of inorganic raw
materials further includes an aluminosilicate source.
14. The method of claim 13 wherein the aluminosilicate source is
selected from the group consisting of mullite, kyanite,
sillimanite, kaolin, calcined kaolin, pyrophyllite, and mixtures
thereof.
15. The method of claim 7 wherein the silica source is selected
from the group consisting of quartz, cristobalite, zeolite,
diatomaceous earth, fused silica, colloidal silica, amorphous
silica, and combinations thereof.
16. The method of claim 7 wherein the titanium dioxide source is
selected from the group consisting of rutile, anatase, amorphous
titania, and mixtures thereof.
17. The method of claim 7 wherein the alumina source and titanium
dioxide source have median particle or agglomerate diameters of at
least 10 microns.
18. The method of claim 7 wherein the metal oxide source is
selected from the group consisting of bismuth oxide, calcium
carbonate, calcium hydroxide, calcium aluminate, calcium titanate,
calcium silicate, yttrium or rare earth oxide, hydroxide,
carbonate, fluoride-carbonate, aluminate, silicate, titanate,
chloride, nitrate, acetate, or other soluble or insoluble salt, a
mixed rare earth concentrate such as bastnasite, calcined
bastnasite, or monazite, and combinations thereof.
19. The method of claim 18 wherein the metal oxide source has a
median particle diameter of less than 5 microns.
20. The method of claim 7 wherein the mixture is shaped by
extrusion through a die to form a honeycomb structure.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a mullite-aluminum titanate
ceramic body that has improved properties for use in high
temperature applications and a method for making the same.
[0002] Porous refractory ceramics have long been used as
particulate filters in hot gas or corrosive environments such as
advanced coal-based gas turbine cycles, municipal and industrial
waste incinerators, and diesel or natural-gas engine exhaust
systems. For such applications, ceramic particulate filters must
possess chemical inertness, thermal shock resistance, high
filtration efficiency, low pressure drop, and adequate strength. In
particular, a diesel particulate filter (DPF) ideally combines low
CTE (for thermal shock resistance), low pressure drop (for engine
efficiency), high filtration efficiency (for removal of most
particles from the exhaust stream), high strength (to survive
handling, canning, and vibration in use), and low cost.
[0003] Candidate materials for DPFs include cordierite, silicon
carbide and aluminum titanate based ceramics. Cordierite is
attractive due to its low cost, low CTE, and good strength.
However, the relatively low volumetric heat capacity (approximately
2.8 J cm.sup.-3 .degree. C.-.sup.-1 at 800K) and low thermal
conductivity of cordierite can result in unacceptably high
temperatures during operation when the filters are regenerated
under certain conditions. Further, obtaining a well-interconnected
pore microstructure in cordierite filters, in combination with low
porosity required for high thermal mass, has been a challenge.
[0004] Silicon carbide filters have an advantage of a
well-interconnected porosity for low pressure drop. Higher
volumetric heat capacity (approximately 3.6 J cm.sup.-3 .degree.
C..sup.-1 at 800K) and high thermal conductivity, coupled with a
very high melting point, make silicon carbide thermally durable.
However, silicon carbide is relatively expensive. Furthermore, the
high coefficient of thermal expansion requires silicon carbide
filters to be fabricated as cement-bonded segments, adding to
manufacturing cost and raising concerns about their long-term
thermo-mechanical durability.
[0005] Aluminum titanate based ceramics and specifically
mullite-aluminum titanate (MAT) ceramics offer a very high
volumetric heat capacity (approximately 3.9 to 4.0 J cm.sup.-3
.degree. C..sup.-1 for fully dense MAT at 800K) in combination with
a low CTE. Further, MAT ceramics have excellent chemical durability
and high melting point.
[0006] However, in the manufacture of MAT bodies sintering
temperatures greater than 1600.degree. C. are often required to
achieve sufficient grain growth for microcracking and low thermal
expansion. Such high heating temperatures add cost to manufacturing
and final product. To reduce the sintering temperature some
approaches have utilized the addition of chemical components.
Nonetheless, such methods often result in a strong sensitivity of
the physical properties, including CTE, porosity, or pore size, to
the firing temperature, which is undesirable for manufacturability.
Also, desired properties for DPF use are not expected to be
achieved. Further, many methods for making aluminum titanate-based
bodies require the use of pre-reacted aluminum titanate and/or
mullite powders, which also increase the manufacturing cost.
[0007] A need therefore exists to have a mullite-aluminum titanate
body that can be manufactured at lower sintering temperatures with
properties that are useful for high temperature filtration
applications.
SUMMARY OF THE INVENTION
[0008] MAT ceramic bodies of the present invention offer low
thermal expansion, high thermal shock resistance, a narrow pore
size distribution and greater interconnectivity of the porosity,
and are fabricated at lower sintering temperatures of between
1375.degree. C.-1550.degree. C. by using a metal oxide sintering
additive in the raw material batch. The metal oxide is added in an
amount of at least 0.10% by weight, in some applications between
0.10%-5.0% by weight, the oxide relating to a metal selected from
the group consisting of yttrium, bismuth, calcium, lanthanide
metals, and combinations thereof.
[0009] In one embodiment the inventive materials exhibit a
coefficient of thermal expansion (RT-1000.degree. C.) less than
15.times.10.sup.-7 C.sup.-1, a porosity of at least 38% by volume,
a median pore diameter of at least 8 micrometers, and a narrow pore
size distribution as characterized by the relation
(d.sub.50-d.sub.10)/d.sub.50 being not more than 0.50 which
corresponds to a high degree of interconnected porosity.
[0010] The inventive bodies are especially useful in high
temperature applications including wall-flow filters for diesel
exhaust filtration. In one such embodiment the filter is a plugged,
honeycomb body composed of the inventive MAT ceramic and exhibiting
a coefficient of thermal expansion or CET (RT-1000.degree. C.) of
not greater than 10.times.10.sup.-7 C.sup.-1, a porosity of between
45-60% by volume, a median pore diameter of between 10-20
micrometers, and a narrow pore size distribution as characterized
by the relation (d.sub.50-d.sub.10)/d.sub.50 being not greater than
0.35 which corresponds to a high degree of interconnected
porosity.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] FIG. 1 is a scanning electron micrograph of the as-fired
surface of Inventive Example 16, showing the unique domain-type
microstructure of radiating crystals;
[0012] FIG. 2 is a scanning electron micrograph of the as-fired
surface of Comparative Example C5, showing the absence of any
groups of radiating crystals;
[0013] FIG. 3 shows the changes in %porosity, median pore diameter,
and mean CTE (RT-1000.degree. C.) as a function of the amount of
Y.sub.2O.sub.3 added to the raw material mixture when fired at
1400.degree. C.;
[0014] FIG. 4 shows the changes in %porosity, median pore diameter,
and mean CTE (RT-1000.degree. C.) as a function of the amount of
Y.sub.2O.sub.3 added to the raw material mixture when fired at
1500.degree. C.;
[0015] FIG. 5 is a scanning electron micrograph of a polished cross
section of Inventive Example 60 showing the high degree of
interconnected porosity of the inventive material;
[0016] FIG. 6 shows the relationship between the pressure drop
versus soot loading behavior of a commercially-available cordierite
DPF, a silicon carbide DPF, and a DPF comprising the ceramic of
Inventive Example 72, each having approximately the same heat
capacity per unit volume; and,
[0017] FIG. 7 shows the values for % porosity, median pore diameter
(microns) and CTE (RT-1000.degree. C., 10.sup.-7 .degree.
C..sup.-1) for Examples 89 to 93 plotted versus the temperature at
which the examples were fired.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0018] The ceramic body of the present invention is composed
primarily of mullite and aluminum titanate phases, while also
including at least 0.10% by weight of one or more metal oxides in
which the metal is selected from the group consisting of bismuth,
calcium, yttrium, lanthanides and combinations thereof. For certain
applications the metal oxide is limited to an amount of between
0.10% to 5.0% by weight.
[0019] It has been observed that the addition of one or more of the
recited metal oxides lowers the coefficient of thermal expansion
and increases the median pore diameter without substantially
reducing the amount of porosity in the fired body. A low CTE is
desired for high thermal shock resistance, while a large median
pore diameter contributes to low pressure drop.
[0020] Furthermore, the metal oxide sintering additives enable the
use of lower sintering temperatures. Also, the physical properties
of the inventive bodies are not sensitive to the firing temperature
employed such that conventional kilns without the need for
sophisticated and expensive temperature controls can be used.
Further, as a result of the metal oxide sintering additives used
the physical properties are not sensitive such that the inventive
MAT bodies can be used at temperatures higher than the sintering
temperatures used, for a period of duration of 5-10 hours or
somewhat more.
[0021] In fabricating the inventive ceramic bodies a raw material
mixture is first provided. The inorganic powders are selected from
sources of: (a) alumina such as corundum, gamma-alumina or another
transitional alumina, boehmite, alumina hydroxide (gibbsite) and
mixtures thereof, (b) aluminosilicate such as mullite, kyanite,
sillimanite, kaolin, calcined kaolin, pyrophyllite and mixtures
thereof, (c) silica such as quartz, cristobalite, zeolite,
diatomaceous earth, a silicon organometallic compound, fused
silica, colloidal silica, other amorphous silica, and combinations
thereof, and (d) titanium dioxide such as rutile, anatase,
amorphous titania, and mixtures thereof. Optionally, pre-reacted
aluminum titanate may be used as a raw material, but is not
required nor desired.
[0022] It is important that in the raw material mixture of powders
the weighted average of the median particle or agglomerate
diameters of the constituent inorganic powders, denoted D.sub.50,
is at least 6 microns. The value of D.sub.50 is calculated as
D.sub.50=.SIGMA.[(w.sub.i)(d.sub.50,i)]/.SIGMA.(w.sub.i) in which
w.sub.i denotes the weight percentage of each inorganic powder
exclusive of the metal oxide sintering additive, and d.sub.50,i is
the median particle or agglomerate diameter of that same inorganic
powder. The particle or agglomerate diameters are measured by a
laser diffraction technique. A weighted average particle size of
less than 6 microns would result in a pore size finer than 8
microns in the final MAT ceramic, contrary to the required
properties of the present invention.
[0023] The alumina source has a median particle size greater than
15 microns. When the particle size of the titania source is greater
than 5 microns the porosity of the body is desirably increased
without the need for large amounts of a pore-forming agent.
Preferably, both the alumina source and titanium dioxide source
have median particle or agglomerate diameters of at least 10
microns.
[0024] The raw material mixture further includes a metal oxide
sintering additive. Suitable metal oxides for purposes of the
present invention include but are not limited to bismuth oxide,
calcium carbonate, calcium hydroxide, calcium aluminate, calcium
titanate, calcium silicate, yttrium or rare earth oxide, hydroxide,
carbonate, fluoride-carbonate, aluminate, silicate, titanate,
chloride, nitrate, acetate, or other soluble or insoluble salt, or
a mixed rare earth concentrate such as bastnasite, calcined
bastnasite, or monazite. The metal oxide sintering additive
preferably has a median particle size of less than 5 microns, or is
in a water-soluble state. The metal oxide additive is present in an
amount of at least 0.10% by weight, or preferably between 0.10% to
5.0% by weight super-addition to the other inorganic raw materials
that react to form aluminum titanate and mullite phases. By
super-addition is meant that to 100 grams of inorganic raw material
mixture are added for example between 0.10 to 5 grams of metal
oxide.
[0025] Optionally, at least 0.05% by weight molybdenum oxide or
tungsten oxide may be added to the raw material mixture. The
addition of a molybdenum oxide or tungsten oxide source to the raw
material mixture increases the amount of porosity in the fired
ceramic, thus requiring less pore forming agent in the raw material
mixture.
[0026] Optionally, a pore former may be added to tailor the
porosity of the final ceramic body. The raw material mixture may
include up to 20.times. grams per 100 grams of the inorganic raw
materials, where X is the density of the pore former particle in
grams per cubic centimeter. The pore forming agent may be any
particulate material that undergoes combustion or vaporization
during heating of the green body so as to leave behind pores after
the sample has been fired.
[0027] Examples of pore forming agents include, but are not
restricted to, graphite, amorphous carbon, cellulose, wood flour,
nut shell flour, starches, and synthetic polymers such as
polyethylene, polystyrene, and polyacrylate. The pore forming agent
preferably has a median particle or agglomerate diameter of between
10-100 microns. Finer particle sizes result in an undesirably finer
pore size and higher pressure drop when the body is used as a
filtration device. Coarser particle sizes yield large pores than
weaken the body and may result in reduced filtration efficiency if
the body is used as a filter.
[0028] The raw materials and pore formers are further mixed with
organic and/or organometallic binders, lubricants, and plasticizers
and aqueous or non-aqueous solvents to form a plastic mixture that
can be shaped by any conventional means such as by molding or
extrusion through a die, such as for example to form a honeycomb
structure. The green-formed body is then dried and fired in air to
a temperature of between 1375.degree. to 1550.degree. C. and held
for approximately 1 to 15 hours before cooling to room
temperature.
[0029] MAT ceramics according to the present invention exhibit a
low coefficient of thermal expansion (CTE) from a microcracked
structure, good thermal durability, good strength, and highly
interconnected porosity. The amount of mullite in the body is
estimated to be between 2-60% by weight, and preferably between
15-40% by weight.
[0030] In one embodiment the inventive ceramic body is
characterized by the following properties: a coefficient of thermal
expansion (RT-1000.degree. C.) less than 15.times.10.sup.-7
C.sup.-1, a porosity of at least 38% by volume, a median pore
diameter of at least 8 micrometers, and a narrow pore size
distribution as characterized by the relation
(d.sub.50-d.sub.10)/d.sub.50 being not more than 0.50 which
corresponds to a high degree of interconnected porosity. The values
d.sub.10 and d.sub.50 are defined as the pore diameters at 10% and
50% of the cumulative pore size distribution based upon volume, as
measured by mercury porosimetry, with d.sub.10<d.sub.50. Thus,
d.sub.50 is the median pore diameter, and d10 is the pore diameter
at which 10% of the pores are finer, based upon volume.
[0031] A narrow pore size distribution corresponds to a greater
interconnectivity of the porosity, which results in a lower
pressure drop under soot-loaded conditions when the body is used as
a diesel particulate filter. The material strength of the MAT
ceramic, as indicated by the modulus of rupture (MOR) using the
four point method on a cylindrical rod, is at least 500 psi.
[0032] In another embodiment the inventive MAT ceramic is used in
the fabrication of filters for diesel exhaust and in particular as
a wall-flow filter. A wall-flow filter comprises a plugged,
honeycomb body having a plurality of parallel end-plugged cell
channels traversing the body from a frontal inlet end to an outlet
end thereof. Such structures are well known in the art. Part of the
total number of cells at the inlet end are plugged along a portion
of their lengths, and the remaining part of cells that are open at
the inlet end are plugged at the outlet end along a portion of
their lengths. This plugging configuration allows for engine
exhaust passing through the cells of the honeycomb from the inlet
end to the outlet end to flow into the open cells, through the cell
walls, and out of the structure through the open cells at the
outlet end. Suitable cellular densities for diesel particulate
filters range from 70 cells/in.sup.2 (10.9 cells/cm.sup.2) to 400
cells/in.sup.2 (62 cells/cm.sup.2).
[0033] In another embodiment a DPF comprising the inventive
material is preferably characterized by the following properties: a
coefficient of thermal expansion (RT-1000.degree. C.) not greater
than 10.times.10.sup.-7 C.sup.-1, a porosity of between 45-60% by
volume, a median pore diameter of between 10-20 micrometers, and a
narrow pore size distribution as characterized by the relation
(d.sub.50-d.sub.10)/d.sub.50 being not greater than 0.35 which
corresponds to a high degree of interconnected porosity.
EXAMPLES
[0034] The invention is further illustrated with the following
non-limiting examples. Inventive and comparative samples are
prepared by admixing the inorganic raw materials, metal oxide
additives, and pore-forming agents with 4 to 6 wt % methyl
cellulose binder, 0.15 wt % triethanol amine, 1% tall oil, and 14
to 18 wt % water. The mixture is plasticized in a stainless steel
muller and extruded as 5/16-inch diameter rod and 1-inch, 2-inch,
or 5.7-inch diameter honeycomb. Parts are dried and then fired in a
gas or electric kiln at 1400.degree. to 1500.degree. C. and held
for 4 to 10 hours.
[0035] After firing, the porosities of the samples are
characterized by mercury porosimetry, the CTEs measured by
dilatometry, and the modulus of rupture (MOR) by the four-point
method on 5/16-in diameter rods. MOR values are reported in pounds
per square inch (psi). Some samples are also crushed and their
crystalline phases identified by powder x-ray diffractometry. Pore
diameters (d.sub.10, d.sub.50 and d.sub.90) are in micrometers. The
meanings of d.sub.10 and d.sub.50 has been defined previously. The
value of d.sub.90 is the pore diameter for which 90% of the pores,
by volume, are finer in diameter thus
d.sub.10<d.sub.50<d.sub.90. Coefficients of thermal expansion
are in units of 10.sup.-7.degree. C..sup.-1.
[0036] Selected 2-inch and 5.7-inch diameter parts, 6-inches long,
are prepared as filters by plugging the ends of alternate channels
on one face, and then plugging the ends of the adjacent channels on
the opposite face, using a cold-set cement. Pressure drops across
the length of the filters are measured at ambient temperature at
air flow rates of 26.25 standard cubic feet per minute (scfm) on
2-inch diameter filters, and 210 scfm on the 5.7-inch diameter
filters. The filters are then progressively loaded with artificial
high surface area carbon soot at loadings from about 0.5
grams/liter to about 4.5 grams/liter, and the pressure drops
measured at the same flow rate for each soot loading. Pressure drop
values reported at 5 g/l soot loading are calculated by linear
extrapolation of the data at lower soot loadings.
[0037] Median particle sizes of the raw materials used in the
present inventive and comparative examples are listed in Table 1.
Raw materials and properties of the examples are provided in Tables
2 to 23. Nominal percentages of aluminum titanate
(Al.sub.2TiO.sub.5) and mullite (3Al.sub.2O.sub.3-2SiO.sub.2) for
each composition are by weight. All raw materials are also in parts
by weight.
[0038] Examples prefixed by the letter "C" denote comparative
(non-inventive) examples. Amounts of phases measured by powder XRD
are denoted as major (M), minor (m), very minor (vm), trace (tr),
small or very small trace (s.tr. and v.s.tr), or absent (0).
Examples in Tables 2 to 19, and 23, were fired in electric
furnaces; those in Tables 20-22 utilized either gas or electric
furnaces, as indicated in the tables. In Tables 2-23, "MPS" denotes
median particle size (diameter) in micrometers. MPS of the
inorganic raw materials is equivalent to D.sub.50 and is also in
micrometers. In the examples of Tables 2 to 23, the MPS of all
inorganic raw materials includes contributions from alumina,
aluminum hydroxide, titania, kaolin, and quartz.
[0039] Examples C1 and C2 in Table 2 show that, in the absence of a
metal oxide addition selected from the inventive group of
compounds, ceramic bodies of aluminum titanate+mullite fired at
1400 or 1500.degree. C. have a CTE greater than 15. Comparative
examples C3 and C4 show that, although the addition of 2.78%
Y.sub.2O.sub.3 reduces the CTE to less than 15, the median pore
size is undesirably less than 8 microns when the weighted average
of the median particle sizes of the inorganic raw materials is less
than 6 microns.
[0040] Table 3 shows that, even when the weighted average of the
median particle sizes of the inorganic raw materials is greater
than 6 microns, the CTEs of the aluminum titanate +mullite ceramics
are greater than 15 and the median pore sizes are less than 8
microns in the absence of a metal oxide addition selected from the
inventive group of compounds, regardless of whether the
compositions are fired at 1400.degree. C. or at 1500.degree. C.
Furthermore, in the absence of the inventive sintering additive,
substantial amounts of unreacted alumina and titania are present
when fired at 1400.degree. C. for these coarse raw materials.
[0041] By contrast, the inventive examples in Table 4 demonstrate
that, when the weighted average of the median particle sizes of the
inorganic raw materials is greater than 6 microns and the raw
materials mixture contains Y.sub.2O.sub.3, the CTEs of the aluminum
titanate +mullite ceramics are less than 7 and the median pore
sizes are greater than 8 microns when at least 1.0 wt %
Y.sub.2O.sub.3 is added to this raw material mixture.
[0042] Examples 2 and 3 further show that the %porosity of the
ceramic bodies is desirably increased by the addition of at least
1.0 wt % MoO.sub.3 to the raw materials. FIG. 1 illustrates that
the microstructure of Inventive Example 16 consists of "domains" of
radiating aluminum titanate crystals. Such domains provide a unique
microstructure that may influence the nature of the microcracking
in the inventive ceramics. This microstructure is contrasted with
that of Comparative Example C5 in FIG. 2, which depicts the lack of
domains when an inventive metal oxide additive is absent.
[0043] The examples in Table 5 illustrate that firing the inventive
compositions at 1500.degree. C. still yields very low CTE and a
median pore size greater than 8 microns while still preserving
desirable high porosities. Thus, the inventive sintering additives
do not result in excessive densification of the ceramic bodies with
increasing temperature, and are therefore conducive to
manufacturing processes that do not require stringent and expensive
control of the firing temperature to within a very narrow
range.
[0044] Tables 6 and 7 provide additional inventive examples based
upon Y.sub.2O.sub.3 with or without MoO.sub.3 for 80% aluminum
titanate/20% mullite and 70% aluminum titanate/30% mullite
compositions using various raw material combinations, some
including kaolin as a source of silica and alumina, sintered at
only 1400.degree. C. Tables 8 and 9 show that inventive properties
are still retained when these compositions are fired at
1500.degree. C.
[0045] Tables 10 and 11 characterize the dependence of the physical
properties of the MAT ceramics on the amount of Y.sub.2O.sub.3
addition to the raw material mixture, and the results are shown in
FIGS. 3 and 4. Table 10 illustrates that when an 80% aluminum
titanate/20% mullite composition in which the weighted average of
the median particle sizes of the inorganic raw materials is 9.3
microns is fired at 1400.degree. C., more than 0.5% Y.sub.2O.sub.3
is required to maintain a median pore size of at least 8 microns
and a CTE less than 15. Table 11 shows that when these compositions
are fired at 1500.degree. C., the amount of Y.sub.2O.sub.3 must be
less than 5% to maintain at least 38% porosity and greater than
0.1% to maintain a median pore size greater than 8 microns. It will
be appreciated that even lower amounts of Y.sub.2O.sub.3 could be
utilized at 1500.degree. C. if the weighted average of the median
particle sizes of the raw materials was greater than 9.3 microns.
FIGS. 3 and 4 show that an amount of Y.sub.2O.sub.3 between 1 and
3% is especially preferred for this raw material combination
because the porosity, pore size, and CTE are relatively stable
within this range of metal oxide addition.
[0046] The examples in Tables 12 and 13 show that, in addition to
yttrium oxide, the oxides of the lanthanides metals, and their
combinations, are effective in obtaining inventive bodies with
useful CTE, porosity, and pore size. Examples 48 and 57 demonstrate
that the lanthanide oxides may be provided in the form of a
calcined ore comprised primarily of the oxides of lanthanum,
cerium, praseodymium, and dysprosium.
[0047] Tables 14 and 15 illustrate that a source of calcium oxide,
in this case calcium carbonate, is also effective as a sintering
additive to promote low CTE and coarse pore size without reducing
porosity. However, sources of the oxides of strontium, indium, and
tin do not constitute inventive additives because they either
result in high CTE or low strength.
[0048] Tables 16 and 17 demonstrate that the oxides of molybdenum,
boron, niobium, tungsten, zinc, and zirconium alone are not
effective sintering additives. However, bismuth oxide does serve as
a useful sintering additive, provided that the firing temperature
is greater than 1400.degree. C., and the raw materials have a
median pore size greater than 6 microns.
[0049] In example C29, the median pore size is smaller than 8
microns because D.sub.50 of the inorganic raw materials is less
than 6 microns. However, it will be appreciated that the median
pore size the MAT ceramic prepared with bismuth oxide addition can
be increased to greater than 8 microns by the use of coarser raw
materials while still preserving a CTE (RT-1000.degree. C.) below
15.times.10.sup.-7.degree. C..sup.-1 and a porosity greater than
38%.
[0050] Table 18 shows that, by increasing the median particle size
of the alumina sources, the median pore size can be increased and a
narrow pore size distribution maintained even when the particle
size of the titania source remains very small. FIG. 5 depicts the
well interconnected porosity of Inventive Example 66.
[0051] The examples in Table 19 illustrate that the particle size
of both the titania and alumina sources can be varied while
maintaining the inventive properties. Coarse titania is especially
useful for increasing the porosity of the fired body without the
need for larger amounts of additional pore forming agent.
[0052] Example 72 also shows that a filter prepared from the
inventive body exhibits a very low clean and soot-loaded pressure
drop as a diesel particulate filter. The full pressure drop versus
soot loading curve measured at room temperature and a flow rate of
210 standard cubic feet per minute is depicted in FIG. 6 and
compared with the pressure drop curves for cordierite and silicon
carbide filters of the same size and approximately the same
volumetric heat capacity measured under the same test
conditions.
[0053] The three filters are all approximately 5.66 inches diameter
and 6 inches in length, and pressure drops were all measured at
room temperature and a flow rate of 210 standard cubic feet per
minute. The cordierite example has a cell density of 190
cells/inch.sup.2 and 0.017 inch walls. The silicon carbide example
has a cell density of 320 cells/inch2 and 0.010 inch walls. The
inventive example has a cell density of 311 cells/inch.sup.2 and
0.011 inch walls. The figure demonstrates the excellent low
pressure drop exhibited by filters of the inventive material.
[0054] The examples of Tables 20 to 22 demonstrate that the CTE,
porosity, and median pore size of the inventive materials do not
change greatly for firing temperatures from 1415 to 1475.degree.
C., and that the inventive properties are obtained whether the body
is fired in an electric kiln or a gas kiln. The properties for
Inventive Examples 89-93 are plotted against the firing temperature
in FIG. 7.
[0055] Table 23 shows the changes in length, CTE, and MOR of an
inventive body after cycling 300 times between 200 and 1100.degree.
C. in air. The small differences after thermal cycling demonstrate
the excellent dimensional and physical stability of the inventive
examples.
[0056] While the invention has been described with respect to a
limited number of embodiments, those skilled in the art, having
benefit of the disclosure, will appreciate that other embodiments
can be devised which do not depart from the scope of the invention
as disclosed herein. Accordingly, the scope of the invention should
be limited only by the attached claims. TABLE-US-00001 TABLE 1
Median Particle Diameter Raw Material (microns) Alumina A 6.8
Alumina B 9.0 Alumina C 9.0 Alumina D 23.8 Alumina E 41.8 Aluminum
hydroxide A 11.5 Aluminum hydroxide B 13.2 Aluminum hydroxide C
21.0 Titania A 0.50 Titania B 13.7 Titania C 22.7 Kaolin A 9.9
Quartz A 3.7 Quartz B 23.4 Quartz C 25.4 Graphite A 35.0 Graphite B
49.0
[0057] TABLE-US-00002 TABLE 2 Example Number C1 C2 C3 C4 %
Al.sub.2TiO.sub.5 80 80 80 80 % Mullite 20 20 20 20 Weight Percent
Y.sub.2O.sub.3 -- -- 2.78 2.78 Alumina A 53.52 53.52 53.52 53.52
Titania A 34.56 34.56 34.56 34.56 Kaolin A 11.92 11.92 11.92 11.92
Graphite A 25.00 25.00 25.00 25.00 MPS Alumina sources 6.8 6.8 6.8
6.8 MPS Titania source 0.50 0.50 0.50 0.50 MPS Quartz -- -- -- --
MPS Inorganic Raw Materials 5.0 5.0 5.0 5.0 Firing and Properties
Firing Temperature (.degree. C.) 1400 1500 1400 1500 Hold Time
(hours) 4 4 4 4 CTE (RT-1000.degree. C.) 44.8 28.1 12.3 5.7 %
Porosity 48.8 51.4 47.9 38.9 d.sub.50 3.9 3.8 5.8 7.4 d.sub.10 --
-- -- -- d.sub.90 -- -- -- -- (d.sub.50-d.sub.10)/d.sub.50 -- -- --
-- (d.sub.90-d.sub.10)/d.sub.50 -- -- -- -- MOR rod (psi) 2335 1490
1141 1073 Al.sub.2TiO.sub.5 M M M M Mullite m m m m Al.sub.2O.sub.3
m 0 tr tr TiO.sub.2 m 0 0 0
[0058] TABLE-US-00003 TABLE 3 Example Number C5 C6 C7 C8 C9 C10 %
Al.sub.2TiO.sub.5 80 90 95 80 90 95 % Mullite 20 10 5 20 10 5
Weight Percent MoO.sub.3 -- -- -- -- -- -- Y.sub.2O.sub.3 -- -- --
-- -- -- Alumina C 41.48 39.94 39.18 41.48 39.94 39.18 Aluminum
20.00 20.00 20.00 20.00 20.00 20.00 hydroxide B Titania A 33.27
37.43 39.51 33.27 37.43 39.51 Quartz A 5.25 2.62 1.31 5.25 2.62
1.31 Graphite A 25.00 25.00 25.00 25.00 25.00 25.00 MPS Alumina
10.4 10.4 10.4 10.4 10.4 10.4 sources MPS Titania 0.50 0.50 0.50
0.50 0.50 0.50 source MPS Quartz 3.7 3.7 3.7 3.7 3.7 3.7 MPS
Inorganic 6.7 6.5 6.4 6.7 6.5 6.4 Raw Materials Firing and
Properties Firing 1400 1400 1400 1500 1500 1500 Temperature
(.degree. C.) Hold Time 4 4 4 4 4 4 (hours) CTE 50.1 44.3 36.8 33.5
28.2 22.7 (RT-1000.degree. C.) % Porosity 49.8 50.4 49.9 52.6 55.4
54.6 d.sub.50 4.4 4.4 4.6 6.7 6.2 6.3 d.sub.10 2.2 2.1 2.1 3.4 3.1
3.2 d.sub.90 9.0 8.7 8.4 14.5 20.6 13.2 (d.sub.50 -
d.sub.10)/d.sub.50 0.50 0.51 0.53 0.50 0.51 0.50 (d.sub.90 -
d.sub.10)/d.sub.50 1.55 1.50 1.36 1.66 2.83 1.60 MOR rod (psi) 2084
1264 1145 2209 1623 1523 Al.sub.2TiO.sub.5 M M M M M M Mullite m tr
0 m tr 0 Al.sub.2O.sub.3 M M M tr m m TiO.sub.2 M M M tr m m
[0059] TABLE-US-00004 TABLE 4 Example Number 1 2 3 4 5 %
Al.sub.2TiO.sub.5 80 80 80 90 95 % Mullite 20 20 20 10 5 Weight
Percent MoO.sub.3 -- 2.61 1.30 -- -- Y.sub.2O.sub.3 2.78 1.39 2.78
2.73 1.35 Alumina C 41.48 41.48 41.48 39.94 39.18 Aluminum
hydroxide B 20.00 20.00 20.00 20.00 20.00 Titania A 33.27 33.27
33.27 37.43 39.51 Quartz A 5.25 5.25 5.25 2.62 1.31 Graphite A
25.00 25.00 25.00 25.00 25.00 MPS Alumina sources 10.4 10.4 10.4
10.4 10.4 MPS Titania source 0.50 0.50 0.50 0.50 0.50 MPS Quartz
3.7 3.7 3.7 3.7 3.7 MPS Inorganic Raw 6.7 6.7 6.7 6.5 6.4 Materials
Firing and Properties Firing Temperature 1400 1400 1400 1400 1400
(.degree. C.) Hold Time (hours) 4 4 4 4 4 CTE (RT-1000.degree. C.)
6.8 4.1 3.2 -0.8 -5.1 % Porosity 51.8 53.7 54.5 45.9 46.4 d.sub.50
9.2 8.5 9.7 8.5 8.3 d.sub.10 5.8 5.3 6.4 6.1 5.7 d.sub.90 17.6 17.9
20.4 30.2 15.1 (d.sub.50 - d.sub.10)/d.sub.50 0.37 0.37 0.34 0.28
0.31 (d.sub.90 - d.sub.10)/d.sub.50 1.28 1.48 1.44 2.83 1.13 MOR
rod (psi) 602 793 586 946 897 Al.sub.2TiO.sub.5 M M M M M Mullite m
m m 0 0 Al.sub.2O.sub.3 tr tr vm tr m TiO.sub.2 vm tr vm tr tr
[0060] TABLE-US-00005 TABLE 5 Example Number 6 7 8 9 10 11 12 %
Al.sub.2TiO.sub.5 80 80 80 80 90 90 95 % Mullite 20 20 20 20 10 10
5 Weight Percent MoO.sub.3 2.61 2.61 1.30 -- -- -- --
Y.sub.2O.sub.3 1.39 2.78 2.78 2.78 1.36 2.73 1.35 Alumina C 41.48
41.48 41.48 41.48 39.94 39.94 39.18 Aluminum hydroxide B 20.00
20.00 20.00 20.00 20.00 20.00 20.00 Titania A 33.27 33.27 33.27
33.27 37.43 37.43 39.51 Quartz A 5.25 5.25 5.25 5.25 2.62 2.62 1.31
Graphite A 25.00 25.00 25.00 25.00 25.00 25.00 25.00 MPS Alumina
sources 10.4 10.4 10.4 10.4 10.4 10.4 10.4 MPS Titania source 0.50
0.50 0.50 0.50 0.50 0.50 0.50 MPS Quartz 3.7 3.7 3.7 3.7 3.7 3.7
3.7 MPS All Inorganic Raw Materials 6.7 6.7 6.7 6.7 6.5 6.5 6.4
Firing and Properties Firing Temperature (.degree. C.) 1500 1500
1500 1500 1500 1500 1500 Hold Time (hours) 4 4 4 4 4 4 4 CTE
(RT-1000.degree. C.) -3.6 -5.9 -2.8 0.8 -4.9 -7.6 -12.5 % Porosity
52.5 50.9 51.8 48.2 47.7 44.9 44.4 d.sub.50 9.8 10.8 11.5 10.4 9.9
10.6 10.5 d.sub.10 6.8 8.3 8.8 8.3 7.0 8.4 8.1 d.sub.90 14.9 15.4
56.4 16.5 17.8 44.0 17.7 (d.sub.50 - d.sub.10)/d.sub.50 0.31 0.23
0.23 0.20 0.29 0.21 0.23 (d.sub.90 - d.sub.10)/d.sub.50 0.83 0.65
4.14 0.78 1.09 3.36 0.91 MOR rod (psi) 1040 1018 842 736 1063 1195
954 Al.sub.2TiO.sub.5 M M M M M M M Mullite m m m m tr tr 0
Al.sub.2O.sub.3 m m m tr tr m tr TiO.sub.2 0 0 tr tr tr tr v s.
tr
[0061] TABLE-US-00006 TABLE 6 Example Number 13 14 15 16 17 %
Al.sub.2TiO.sub.5 80 80 80 80 80 % Mullite 20 20 20 20 20 Weight
Percent MoO.sub.3 2.00 2.00 -- 2.00 -- Y.sub.2O.sub.3 2.00 2.00
2.00 2.00 2.00 Alumina C 41.48 41.48 41.48 36.18 36.18 Aluminum
hydroxide C 20.00 20.00 20.00 20.00 20.00 Titania A 33.27 33.27
33.27 32.73 32.73 Kaolin A -- -- -- 11.09 11.09 Quartz B 5.25 5.25
5.25 -- -- Graphite A 25.00 -- -- -- -- Graphite B -- 25.00 25.00
25.00 25.00 MPS Alumina sources 12.9 12.9 12.9 13.3 13.3 MPS
Titania source 0.50 0.50 0.50 0.50 0.50 MPS Quartz 23.4 23.4 23.4
-- -- MPS All Inorganic 9.3 9.3 9.3 8.7 8.7 Raw Materials Firing
and Properties Firing Temperature 1400 1400 1400 1400 1400
(.degree. C.) Hold Time (hours) 4 4 4 4 4 CTE (RT-1000.degree. C.)
6.6 0.5 8.3 1.7 4.8 % Porosity 49.2 52.1 49.5 53.4 51.2 d.sub.50
10.1 11.1 10.5 8.6 8.6 d.sub.10 6.3 6.7 6.0 4.9 4.6 d.sub.90 14.2
13.1 23.4 17.7 19.7 (d.sub.50 - d.sub.10)/d.sub.50 0.37 0.40 0.42
0.43 0.46 (d.sub.90 - d.sub.10)/d.sub.50 0.79 0.58 1.65 1.48 1.76
MOR rod (psi) 710 721 793 604 768 Al.sub.2TiO.sub.5 M M M M M
Mullite m m m m m Al.sub.2O.sub.3 tr tr tr tr tr TiO.sub.2 tr tr tr
tr tr
[0062] TABLE-US-00007 TABLE 7 Example Number 18 19 20 21 22 %
Al.sub.2TiO.sub.5 70 70 70 70 70 % Mullite 30 30 30 30 30 Weight
Percent MoO.sub.3 2.00 2.00 -- 2.00 -- Y.sub.2O.sub.3 2.00 2.00
2.00 2.00 2.00 Alumina C 43.01 43.01 43.01 35.10 35.10 Aluminum
hydroxide C 20.00 20.00 20.00 20.00 20.00 Titania A 29.12 29.12
29.12 28.40 28.40 Kaolin A -- -- -- 16.50 16.50 Quartz B 7.87 7.87
7.87 -- -- Graphite A 25.00 -- -- -- -- Graphite B -- 25.00 25.00
25.00 25.00 MPS Alumina sources 12.8 12.8 12.8 13.4 13.4 MPS
Titania source 0.50 0.50 0.50 0.50 0.50 MPS Quartz 23.4 23.4 23.4
-- -- MPS All Inorganic 10.1 10.1 10.1 9.1 9.1 Raw Materials Firing
and Properties Firing Temperature 1400 1400 1400 1400 1400
(.degree. C.) Hold Time (hours) 4 4 4 4 4 CTE (RT-1000.degree. C.)
8.9 8.6 8.4 14.0 14.1 % Porosity 51.5 53.9 52.7 53.8 54.0 d.sub.50
10.3 11.1 11.3 8.1 8.1 d.sub.10 6.1 5.9 5.8 4.4 4.0 d.sub.90 15.3
21.2 22.9 14.9 18.8 (d.sub.50 - d.sub.10)/d.sub.50 0.41 0.47 0.48
0.46 0.50 (d.sub.90 - d.sub.10)/d.sub.50 0.89 1.39 1.52 1.30 1.81
MOR rod (psi) 876 663 1091 726 765 Al.sub.2TiO.sub.5 M M M M M
Mullite m m m m m Al.sub.2O.sub.3 tr tr tr v.s.tr s.tr TiO.sub.2 tr
tr tr v.s.tr s.tr
[0063] TABLE-US-00008 TABLE 8 Example Number 23 24 25 26 27 %
Al.sub.2TiO.sub.5 80 80 80 80 80 % Mullite 20 20 20 20 20 Weight
Percent MoO.sub.3 2.00 2.00 -- 2.00 -- Y.sub.2O.sub.3 2.00 2.00
2.00 2.00 2.00 Alumina C 41.48 41.48 41.48 36.18 36.18 Aluminum
hydroxide C 20.00 20.00 20.00 20.00 20.00 Titania A 33.27 33.27
33.27 32.73 32.73 Kaolin A -- -- -- 11.09 11.09 Quartz B 5.25 5.25
5.25 -- -- Graphite A 25.00 -- -- -- -- Graphite B -- 25.00 25.00
25.00 25.00 MPS Alumina sources 12.9 12.9 12.9 13.3 13.3 MPS
Titania source 0.50 0.50 0.50 0.50 0.50 MPS Quartz 23.4 23.4 23.4
-- -- MPS All Inorganic 9.3 9.3 9.3 8.7 8.7 Raw Materials Firing
and Properties Firing Temperature 1500 1500 1500 1500 1500
(.degree. C.) Hold Time (hours) 4 4 4 4 4 CTE (RT-1000.degree. C.)
-2.0 -8.4 0.1 -4.5 -2.2 % Porosity 47.6 50.2 47.0 50.7 47.3
d.sub.50 11.2 11.6 11.6 10.0 10.0 d.sub.10 8.2 -- 7.6 6.5 6.8
d.sub.90 37.3 -- 20.8 19.4 19.2 (d.sub.50 - d.sub.10)/d.sub.50 0.27
-- 0.34 0.35 0.32 (d.sub.90 - d.sub.10)/d.sub.50 2.60 -- 1.14 1.29
1.24 MOR rod (psi) 593 489 706 489 670 Al.sub.2TiO.sub.5 M M M M M
Mullite m m m m m Al.sub.2O.sub.3 v.s.tr v.s.tr s.tr s.tr tr
TiO.sub.2 v.s.tr v.s.tr s.tr v.s.tr v.s.tr
[0064] TABLE-US-00009 TABLE 9 Example Number 28 29 30 31 32 %
Al.sub.2TiO.sub.5 70 70 70 70 70 % Mullite 30 30 30 30 30 Weight
Percent MoO.sub.3 2.00 2.00 -- 2.00 -- Y.sub.2O.sub.3 2.00 2.00
2.00 2.00 2.00 Alumina C 43.01 43.01 43.01 35.10 35.10 Aluminum
hydroxide C 20.00 20.00 20.00 20.00 20.00 Titania A 29.12 29.12
29.12 28.40 28.40 Kaolin A -- -- -- 16.50 16.50 Quartz B 7.87 7.87
7.87 -- -- Graphite A 25.00 -- -- -- -- Graphite B -- 25.00 25.00
25.00 25.00 MPS Alumina sources 12.8 12.8 12.8 13.4 13.4 MPS
Titania source 0.50 0.50 0.50 0.50 0.50 MPS Quartz 23.4 23.4 23.4
-- -- MPS All Inorganic 10.1 10.1 10.1 9.1 9.1 Raw Materials Firing
and Properties Firing Temperature 1500 1500 1500 1500 1500
(.degree. C.) Hold Time (hours) 4 4 4 4 4 CTE (RT-1000.degree. C.)
2.9 0.6 0.7 3.3 2.8 % Porosity 49.2 53.7 50.0 49.3 49.8 d.sub.50
11.0 12.6 12.4 9.1 9.4 d.sub.10 7.5 8.1 7.8 5.5 5.7 d.sub.90 16.2
20.1 27.0 25.2 19.8 (d.sub.50 - d.sub.10)/d.sub.50 0.32 0.36 0.37
0.39 0.40 (d.sub.90 - d.sub.10)/d.sub.50 0.79 0.96 1.55 2.16 1.51
MOR rod (psi) 694 630 780 753 728 Al.sub.2TiO.sub.5 M M M M M
Mullite m m m m m Al.sub.2O.sub.3 s.tr v.s.tr v.s.tr v.s.tr v.s.tr
TiO.sub.2 v.s.tr v.s.tr v.s.tr 0 v.s.tr
[0065] TABLE-US-00010 TABLE 10 Example Number 33 34 35 C11 C12 C13
% Al.sub.2TiO.sub.5 80 80 80 80 80 80 % Mullite 20 20 20 20 20 20
Weight Percent Y.sub.2O.sub.3 5.00 2.00 1.00 0.50 0.20 0.10 Alumina
C 41.48 41.48 41.48 41.48 41.48 41.48 Aluminum 20.00 20.00 20.00
20.00 20.00 20.00 hydroxide C Titania A 33.27 33.27 33.27 33.27
33.27 33.27 Quartz B 5.25 5.25 5.25 5.25 5.25 5.25 Graphite A 25.00
25.00 25.00 25.00 25.00 25.00 MPS Alumina 12.9 12.9 12.9 12.9 12.9
12.9 sources MPS Titania 0.50 0.50 0.50 0.50 0.50 0.50 source MPS
Quartz 23.4 23.4 23.4 23.4 23.4 23.4 MPS All 9.3 9.3 9.3 9.3 9.3
9.3 Inorganic Raw Materials Firing and Properties Firing 1400 1400
1400 1400 1400 1400 Temperature (.degree. C.) Hold Time 4 4 4 4 4 4
(hours) CTE 6.0 5.7 9.2 14.9 21.9 35.5 (RT-1000.degree. C.) %
Porosity 44.7 48.0 52.2 51.4 47.6 49.3 d.sub.50 9.9 9.2 8.8 7.2 6.0
5.8 d.sub.10 -- -- -- -- -- -- d.sub.90 -- -- -- -- -- -- (d.sub.50
- d.sub.10)/d.sub.50 -- -- -- -- -- -- (d.sub.90 -
d.sub.10)/d.sub.50 -- -- -- -- -- -- MOR rod (psi) 1213 1174 1450
916 1003 1048 Al.sub.2TiO.sub.5 -- -- -- -- -- -- Mullite -- -- --
-- -- -- Al.sub.2O.sub.3 -- -- -- -- -- -- TiO.sub.2 -- -- -- -- --
--
[0066] TABLE-US-00011 TABLE 11 Example Number C14 36 37 38 39 C15 %
Al.sub.2TiO.sub.5 80 80 80 80 80 80 % Mullite 20 20 20 20 20 20
Weight Percent Y.sub.2O.sub.3 5.00 2.00 1.00 0.50 0.20 0.10 Alumina
C 41.48 41.48 41.48 41.48 41.48 41.48 Aluminum 20.00 20.00 20.00
20.00 20.00 20.00 hydroxide C Titania A 33.27 33.27 33.27 33.27
33.27 33.27 Quartz B 5.25 5.25 5.25 5.25 5.25 5.25 Graphite A 25.00
25.00 25.00 25.00 25.00 25.00 MPS Alumina 12.9 12.9 12.9 12.9 12.9
12.9 sources MPS Titania 0.50 0.50 0.50 0.50 0.50 0.50 source MPS
Quartz 23.4 23.4 23.4 23.4 23.4 23.4 MPS All 9.3 9.3 9.3 9.3 9.3
9.3 Inorganic Raw Materials Firing and Properties Firing 1500 1500
1500 1500 1500 1500 Temperature (.degree. C.) Hold Time 4 4 4 4 4 4
(hours) CTE -0.9 -2.8 -2.1 3.8 6.5 10.7 (RT-1000.degree. C.) %
Porosity 36.8 47.2 49.9 51.2 52.6 55.2 d.sub.50 13.5 10.6 10.1 9.1
8.0 7.7 d.sub.10 -- -- -- -- -- -- d.sub.90 -- -- -- -- -- --
(d.sub.50 - d.sub.10)/d.sub.50 -- -- -- -- -- -- (d.sub.90 -
d.sub.10)/d.sub.50 -- -- -- -- -- -- MOR rod (psi) 942 751 819 808
831 909 Al.sub.2TiO.sub.5 -- -- -- -- -- -- Mullite -- -- -- -- --
-- Al.sub.2O.sub.3 -- -- -- -- -- -- TiO.sub.2 -- -- -- -- --
--
[0067] TABLE-US-00012 TABLE 12 Example Number 40 41 42 43 44 45 46
47 48 % Al.sub.2TiO.sub.5 70 70 70 70 70 70 70 70 70 % Mullite 30
30 30 30 30 30 30 30 30 Weight Percent Y.sub.2O.sub.3 2.63 -- -- --
-- -- -- -- -- CeO.sub.2 -- 3.84 -- -- -- -- -- -- --
La.sub.2O.sub.3 -- -- 3.42 -- -- -- -- -- -- Nd.sub.2O.sub.3 -- --
-- 3.81 -- -- -- -- -- Pr.sub.6O.sub.11 -- -- -- -- 3.63 -- -- --
-- Sm.sub.2O.sub.3 -- -- -- -- -- 3.89 -- -- -- Gd.sub.2O.sub.3 --
-- -- -- -- -- 3.90 -- -- Dy.sub.2O.sub.3 -- -- -- -- -- -- -- 4.10
-- Calcined Bastnasite -- -- -- -- -- -- -- -- 4.90 Alumina C 43.01
43.01 43.01 43.01 43.01 43.01 43.01 43.01 43.01 Aluminum hydroxide
C 20.00 20.00 20.00 20.00 20.00 20.00 20.00 20.00 20.00 Titania A
29.12 29.12 29.12 29.12 29.12 29.12 29.12 29.12 29.12 Quartz C 7.87
7.87 7.87 7.87 7.87 7.87 7.87 7.87 7.87 Graphite A 25.00 25.00
25.00 25.00 25.00 25.00 25.00 25.00 25.00 MPS Alumina sources 12.8
12.8 12.8 12.8 12.8 12.8 12.8 12.8 12.8 MPS Titania source 0.50
0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 MPS Quartz 25.4 25.4 25.4
25.4 25.4 25.4 25.4 25.4 25.4 MPS Inorganic Raw 10.2 10.2 10.2 10.2
10.2 10.2 10.2 10.2 10.2 Materials Firing and Properties Firing
Temperature (.degree. C.) 1400 1400 1400 1400 1400 1400 1400 1400
1400 Hold Time (hours) 4 4 4 4 4 4 4 4 4 CTE (RT-1000.degree. C.)
5.7 8.2 11.9 6.1 6.4 8.9 11.0 7.4 11.4 % Porosity 47.7 39.6 42.1
39.9 40.5 43.2 44.4 48.4 45.1 d.sub.50 9.9 11.8 9.3 10.5 10.2 11.0
9.8 10.4 11.6 d.sub.10 -- -- -- -- -- -- -- -- -- d.sub.90 -- -- --
-- -- -- -- -- -- (d.sub.50 - d.sub.10)/d.sub.50 -- -- -- -- -- --
-- -- -- (d.sub.90 - d.sub.10)/d.sub.50 -- -- -- -- -- -- -- -- --
MOR rod (psi) 1055 1362 1504 1299 1193 1270 1155 1015 1355
Al.sub.2TiO.sub.5 -- -- -- -- -- -- -- -- -- Mullite -- -- -- -- --
-- -- -- -- Al.sub.2O.sub.3 -- -- -- -- -- -- -- -- -- TiO.sub.2 --
-- -- -- -- -- -- -- --
[0068] TABLE-US-00013 TABLE 13 Example Number 49 50 51 52 53 54 55
56 57 % Al.sub.2TiO.sub.5 70 70 70 70 70 70 70 70 70 % Mullite 30
30 30 30 30 30 30 30 30 Weight Percent Y.sub.2O.sub.3 2.63 -- -- --
-- -- -- -- -- CeO.sub.2 -- 3.84 -- -- -- -- -- -- --
La.sub.2O.sub.3 -- -- 3.42 -- -- -- -- -- -- Nd.sub.2O.sub.3 -- --
-- 3.81 -- -- -- -- -- Pr.sub.6O.sub.11 -- -- -- -- 3.63 -- -- --
-- Sm.sub.2O.sub.3 -- -- -- -- -- 3.89 -- -- -- Gd.sub.2O.sub.3 --
-- -- -- -- -- 3.90 -- -- Dy.sub.2O.sub.3 -- -- -- -- -- -- -- 4.10
-- Calcined Bastnasite -- -- -- -- -- -- -- -- 4.90 Alumina C 43.01
43.01 43.01 43.01 43.01 43.01 43.01 43.01 43.01 Aluminum hydroxide
C 20.00 20.00 20.00 20.00 20.00 20.00 20.00 20.00 20.00 Titania A
29.12 29.12 29.12 29.12 29.12 29.12 29.12 29.12 29.12 Quartz C 7.87
7.87 7.87 7.87 7.87 7.87 7.87 7.87 7.87 Graphite A 25.00 25.00
25.00 25.00 25.00 25.00 25.00 25.00 25.00 MPS Alumina sources 12.8
12.8 12.8 12.8 12.8 12.8 12.8 12.8 12.8 MPS Titania source 0.50
0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 MPS Quartz 25.4 25.4 25.4
25.4 25.4 25.4 25.4 25.4 25.4 MPS Inorganic Raw 10.2 10.2 10.2 10.2
10.2 10.2 10.2 10.2 10.2 Materials Firing and Properties Firing
Temperature (.degree. C.) 1500 1500 1500 1500 1500 1500 1500 1500
1500 Hold Time (hours) 4 4 4 4 4 4 4 4 4 CTE (RT-1000.degree. C.)
-0.9 1.0 4.6 3.5 2.7 1.5 1.0 0.0 4.3 % Porosity 43.7 41.4 42.9 40.2
38.7 42.4 44.0 44.9 44.2 d.sub.50 12.0 13.2 10.8 12.2 12.3 12.9
11.9 12.3 13.7 d.sub.10 -- -- -- -- -- -- -- -- -- d.sub.90 -- --
-- -- -- -- -- -- -- (d.sub.50 - d.sub.10)/d.sub.50 -- -- -- -- --
-- -- -- -- (d.sub.90 - d.sub.10)/d.sub.50 -- -- -- -- -- -- -- --
-- MOR rod (psi) 931 1106 1188 1218 1208 1095 1011 940 1011
Al.sub.2TiO.sub.5 -- -- -- -- -- -- -- -- -- Mullite -- -- -- -- --
-- -- -- -- Al.sub.2O.sub.3 -- -- -- -- -- -- -- -- -- TiO.sub.2 --
-- -- -- -- -- -- -- --
[0069] TABLE-US-00014 TABLE 14 Example Number 58 59 C16 C17 C18 %
Al.sub.2TiO.sub.5 80 80 80 80 80 % Mullite 20 20 20 20 20 Weight
Percent Y.sub.2O.sub.3 2.78 -- -- -- -- CaCO.sub.3 -- 1.88 -- --
SrCO.sub.3 -- -- 2.61 -- -- In.sub.2O.sub.3 -- -- -- 3.88 --
SnO.sub.2 -- -- -- -- 3.86 Alumina C 41.48 41.48 41.48 41.48 41.48
Aluminum hydroxide C 20.00 20.00 20.00 20.00 20.00 Titania A 33.27
33.27 33.27 33.27 33.27 Quartz B 5.25 5.25 5.25 5.25 5.25 Quartz C
-- -- -- -- -- Graphite A 25.00 25.00 25.00 25.00 25.00 MPS Alumina
sources 12.9 12.9 12.9 12.9 12.9 MPS Titania source 0.50 0.50 0.50
0.50 0.50 MPS Quartz 23.4 23.4 23.4 23.4 23.4 MPS All Inorganic 9.3
9.3 9.3 9.3 9.3 Raw Materials Firing and Properties Firing
Temperature 1400 1400 1400 1400 1400 (.degree. C.) Hold Time
(hours) 4 4 4 4 4 CTE (RT-1000.degree. C.) 5.3 14.0 30.0 45.3 63.4
% Porosity 47.7 49.8 48.7 52.7 48.1 d.sub.50 9.4 10.4 7.6 6.1 4.2
d.sub.10 -- -- -- -- -- d.sub.90 -- -- -- -- -- (d.sub.50 -
d.sub.10)/d.sub.50 -- -- -- -- -- (d.sub.90 - d.sub.10)/d.sub.50 --
-- -- -- -- MOR rod (psi) 904 1207 1266 877 1778 Al.sub.2TiO.sub.5
M M M M M Mullite m 0 0 m m Al.sub.2O.sub.3 tr m m m M TiO.sub.2 tr
m m M M
[0070] TABLE-US-00015 TABLE 15 Example Number 60 61 C19 C20 C21 %
Al.sub.2TiO.sub.5 80 80 80 80 80 % Mullite 20 20 20 20 20 Weight
Percent Y.sub.2O.sub.3 2.78 -- -- -- -- CaCO.sub.3 -- 1.88 -- -- --
SrCO.sub.3 -- -- 2.61 -- -- In.sub.2O.sub.3 -- -- -- 3.88 --
SnO.sub.2 -- -- -- 3.86 Alumina C 41.48 41.48 41.48 41.48 41.48
Aluminum hydroxide C 20.00 20.00 20.00 20.00 20.00 Titania A 33.27
33.27 33.27 33.27 33.27 Quartz B 5.25 5.25 5.25 5.25 5.25 Graphite
A 25.00 25.00 25.00 25.00 25.00 MPS Alumina sources 12.9 12.9 12.9
12.9 12.9 MPS Titania source 0.50 0.50 0.50 0.50 0.50 MPS Quartz
23.4 23.4 23.4 23.4 23.4 MPS All Inorganic 9.3 9.3 9.3 9.3 9.3 Raw
Materials Firing and Properties Firing Temperature 1500 1500 1500
1500 1500 (.degree. C.) Hold Time (hours) 4 4 4 4 4 CTE
(RT-1000.degree. C.) -1.6 11.3 16.9 12.1 28.6 % Porosity 44.9 44.0
49.5 53.7 54.8 d.sub.50 11.4 10.4 10.5 11.6 6.9 d.sub.10 -- -- --
-- -- d.sub.90 -- -- -- -- -- (d.sub.50 - d.sub.10)/d.sub.50 -- --
-- -- -- (d.sub.90 - d.sub.10)/d.sub.50 -- -- -- -- -- MOR rod
(psi) 823 873 828 480 765 Al.sub.2TiO.sub.5 M M M M M Mullite m tr
0 m m Al.sub.2O.sub.3 tr m m v.s.tr tr TiO.sub.2 v.s.tr tr m tr
tr
[0071] TABLE-US-00016 TABLE 16 Example Number C22 C23 C24 C25 C26
C27 C28 % Al.sub.2TiO.sub.5 80 80 80 80 80 80 80 % Mullite 20 20 20
20 20 20 20 Weight Percent Bi.sub.2O.sub.3 4.75 -- -- -- -- -- --
MoO.sub.3 -- 2.61 -- -- -- -- -- B.sub.2O.sub.3 -- -- 1.37 -- -- --
-- Nb.sub.2O.sub.5 -- -- -- 2.48 -- -- -- WO.sub.3 -- -- -- -- 3.98
-- -- ZnO -- -- -- -- -- 3.11 -- ZrO.sub.2 -- -- -- -- -- -- 3.11
Alumina A 53.52 53.52 53.52 53.52 53.52 53.52 53.52 Titania A 34.56
34.56 34.56 34.56 34.56 34.56 34.56 Kaolin A 11.92 11.92 11.92
11.92 11.92 11.92 11.92 Graphite A 25.00 25.00 25.00 25.00 25.00
25.00 25.00 MPS Alumina sources 6.8 6.8 6.8 6.8 6.8 6.8 6.8 MPS
Titania source 0.50 0.50 0.50 0.50 0.50 0.50 0.50 MPS Quartz -- --
-- -- -- -- -- MPS All Inorganic Raw Materials 5.0 5.0 5.0 5.0 5.0
5.0 5.0 Firing and Properties Firing Temperature (.degree. C.) 1400
1400 1400 1400 1400 1400 1400 Hold Time (hours) 4 4 4 4 4 4 4 CTE
(RT-1000.degree. C.) 37.1 26.4 36.5 41.4 50.6 36.5 43.7 % Porosity
49.1 52.3 51.8 51.0 53.8 47.9 50.2 d.sub.50 5.2 4.5 4.1 2.8 2.8 3.7
3.0 d.sub.10 -- -- -- -- -- -- -- d.sub.90 -- -- -- -- -- -- --
(d.sub.50 - d.sub.10)/d.sub.50 -- -- -- -- -- -- -- (d.sub.50 -
d.sub.10)/d.sub.50 -- -- -- -- -- -- -- MOR rod (psi) 1416 1164
1599 2165 1817 1827 2094 Al.sub.2TiO.sub.5 M M M M M M M Mullite m
m m m m m m Al.sub.2O.sub.3 m tr tr M M 0 tr TiO.sub.2 m tr m M M
tr 0
[0072] TABLE-US-00017 TABLE 17 Example Number C29 C30 C31 C32 C33
C34 C35 % Al.sub.2TiO.sub.5 80 80 80 80 80 80 80 % Mullite 20 20 20
20 20 20 20 Weight Percent Bi.sub.2O.sub.3 4.75 -- -- -- -- -- --
MoO.sub.3 -- 2.61 -- -- -- -- -- B.sub.2O.sub.3 -- -- 1.37 -- -- --
-- Nb.sub.2O.sub.5 -- -- -- 2.48 -- -- -- WO.sub.3 -- -- -- -- 3.98
-- -- ZnO -- -- -- -- -- 3.11 -- ZrO.sub.2 -- -- -- -- -- -- 3.11
Alumina A 53.52 53.52 53.52 53.52 53.52 53.52 53.52 Titania A 34.56
34.56 34.56 34.56 34.56 34.56 34.56 Kaolin A 11.92 11.92 11.92
11.92 11.92 11.92 11.92 Graphite A 25.00 25.00 25.00 25.00 25.00
25.00 25.00 MPS Alumina sources 6.8 6.8 6.8 6.8 6.8 6.8 6.8 MPS
Titania source 0.50 0.50 0.50 0.50 0.50 0.50 0.50 MPS Quartz -- --
-- -- -- -- -- MPS All Inorganic Raw Materials 5.0 5.0 5.0 5.0 5.0
5.0 5.0 Firing and Properties Firing Temperature (.degree. C.) 1500
1500 1500 1500 1500 1500 1500 Hold Time (hours) 4 4 4 4 4 4 4 CTE
(RT-1000.degree. C.) 9.0 16.5 30.3 26.2 24.8 24.7 20.0 % Porosity
41.9 55.1 51.8 48.6 51.4 46.7 50.7 d.sub.50 5.1 4.0 4.1 5.0 5.2 4.3
4.9 d.sub.10 -- -- -- -- -- -- -- d.sub.90 -- -- -- -- -- -- --
(d.sub.50 - d.sub.10)/d.sub.50 -- -- -- -- -- -- -- (d.sub.90 -
d.sub.10)/d.sub.50 -- -- -- -- -- -- -- MOR rod (psi) 966 881 1120
1131 959 1343 1027 Al.sub.2TiO.sub.5 M M M M M M M Mullite m m m m
m m m Al.sub.2O.sub.3 tr tr v.s.tr 0 tr 0 0 TiO.sub.2 tr tr v.s.tr
tr m 0 0
[0073] TABLE-US-00018 TABLE 18 Example Number 63 64 65 66 67 68 69
70 % Al.sub.2TiO.sub.5 70 70 70 70 70 70 70 70 % Mullite 30 30 30
30 30 30 30 30 Weight Percent Y.sub.2O.sub.3 2.63 2.63 2.63 2.63
2.63 2.63 2.63 2.63 Alumina A -- -- -- -- -- -- -- -- Alumina B
43.01 -- -- -- 43.01 -- -- -- Alumina C -- 43.01 -- -- -- 43.01 --
-- Alumina D -- -- 43.01 -- -- -- 43.01 -- Alumina E -- -- -- 43.01
-- -- -- 43.01 Aluminum hydroxide C 20.00 20.00 20.00 20.00 20.00
20.00 20.00 20.00 Titania A 29.12 29.12 29.12 29.12 29.12 29.12
29.12 29.12 Quartz C 7.87 7.87 7.87 7.87 7.87 7.87 7.87 7.87
Graphite A 25.00 25.00 25.00 25.00 25.00 25.00 25.00 25.00 MPS
Alumina sources 12.8 12.8 22.9 35.2 12.8 12.8 22.9 35.2 MPS Titania
source 0.50 0.50 0.50 0.50 0.50 0.50 0.50 0.50 MPS Quartz 25.4 25.4
25.4 25.4 25.4 25.4 25.4 25.4 MPS Inorganic Raw Materials 10.2 10.2
16.6 24.3 10.2 10.2 16.6 24.3 Firing and Properties Firing
Temperature (.degree. C.) 1400 1400 1400 1400 1500 1500 1500 1500
Hold Time (hours) 4 4 4 4 4 4 4 4 CTE (RT-1000.degree. C.) 10.4 9.8
7.5 6.1 1.4 2.8 -0.7 -3.8 % Porosity 44.7 50.3 48.2 50.0 41.6 45.2
47.8 48.4 d.sub.50 8.7 10.0 13.7 17.6 9.8 11.4 15.1 21.4 d.sub.10
5.8 6.5 9.5 12.8 7.3 8.3 10.6 15.0 d.sub.90 12.4 15.5 20.1 26.5
13.7 20.2 26.9 31.2 (d.sub.50 - d.sub.10)/d.sub.50 0.33 0.35 0.31
0.27 0.25 0.27 0.30 0.30 (d.sub.90 - d.sub.10)/d.sub.50 0.76 0.90
0.78 0.78 0.65 1.05 1.08 0.75 MOR rod (psi) 1439 1174 959 710 1175
1017 753 505 Al.sub.2TiO.sub.5 -- -- -- -- -- -- -- -- Mullite --
-- -- -- -- -- -- -- Al.sub.2O.sub.3 -- -- -- -- -- -- -- --
TiO.sub.2 -- -- -- -- -- -- -- --
[0074] TABLE-US-00019 TABLE 19 Example Number 71 72 73 74 75 %
Al.sub.2TiO.sub.5 70 70 70 70 70 % Mullite 30 30 30 30 30 Weight
Percent Y.sub.2O.sub.3 2.50 2.50 2.63 2.63 2.50 Alumina C -- --
43.01 43.01 43.01 Alumina E 43.01 43.01 -- -- -- Aluminum hydroxide
C 20.00 20.00 20.00 20.00 20.00 Titania A 29.12 29.12 -- -- --
Titania B -- -- 29.12 29.12 -- Titania C -- -- -- -- 31.83 Quartz C
7.87 7.87 7.87 7.87 7.87 Graphite A 25.00 25.00 25.00 25.00 25.00
MPS Alumina sources 35.2 35.2 12.8 12.8 12.8 MPS Titania source
0.50 0.50 13.69 13.69 22.68 MPS Quartz 25.4 25.4 25.4 25.4 25.4 MPS
All Inorganic Raw Materials 24.3 24.3 14.1 14.1 16.8 Firing and
Properties Firing Temperature (.degree. C.) 1450 1450 1400 1500
1450 Hold Time (hours) 6 8 4 4 6 CTE (RT-1000.degree. C.) 0.8 -2.7
12.5 5.1 6.3 % Porosity 48.4 49.0 56.9 53.9 58.0 d.sub.50 18.1 18.8
13.3 15.5 12.4 d.sub.10 12.2 12.7 9.8 11.8 10.2 d.sub.90 26.4 30.8
17.6 19.7 22.3 (d.sub.50 - d.sub.10)/d.sub.50 0.33 0.32 0.26 0.24
0.18 (d.sub.90 - d.sub.10)/d.sub.50 0.78 0.97 0.59 0.51 0.97 MOR
rod (psi) -- -- 646 520 -- Diameter (cm) -- 14.46 -- -- -- Height
(cm) -- 15.29 -- -- -- Cells per square inch -- 311 -- -- -- Wall
Thickness (10.sup.-3 in) -- 11.2 -- -- -- Mass (g) -- 1713 -- -- --
Approx. Filter Bulk Density (g/cm.sup.3) -- 0.681 -- -- -- Pressure
drop at 0 g/L, 210 scfm (kPa) -- 1.54 -- -- -- Pressure drop at 5
g/L, 210 scfm (kPa) -- 3.87 -- -- --
[0075] TABLE-US-00020 TABLE 20 Example Number 76 77 78 79 80 81 %
Al.sub.2TiO.sub.5 80 80 80 80 80 80 % Mullite 20 20 20 20 20 20
Weight Percent MoO.sub.3 2.00 2.00 2.00 2.00 2.00 2.00
Y.sub.2O.sub.3 2.00 2.00 2.00 2.00 2.00 2.00 Alumina C 41.48 41.48
41.48 41.48 41.48 41.48 Aluminum hydroxide A 20.00 20.00 20.00
20.00 20.00 20.00 Titania A 33.27 33.27 33.27 33.27 33.27 33.27
Quartz A 5.25 5.25 5.25 5.25 5.25 5.25 Graphite A 25.00 25.00 25.00
25.00 25.00 25.00 MPS Alumina sources 9.8 9.8 9.8 9.8 9.8 9.8 MPS
Titania source 0.5 0.5 0.5 0.5 0.5 0.5 MPS Quartz 3.7 3.7 3.7 3.7
3.7 3.7 MPS All Inorganic Raw Materials 6.4 6.4 6.4 6.4 6.4 6.4
Firing and Properties Firing Temperature (.degree. C.) 1415 1435
1435 1435 1455 1475 Hold Time (hours) 8 6 6 6 6 6 Kiln Type (E =
electric, G = gas) E G E G G E CTE (RT-1000.degree. C.) -2.3 -3.6
-4.1 1.1 -0.2 -6.1 % Porosity 50.5 48.7 49.3 51.1 50.0 47.7
d.sub.50 10.0 9.2 9.7 9.7 9.9 10.4 d.sub.10 -- -- 6.4 -- -- --
d.sub.90 -- -- 13.7 -- -- -- (d.sub.50 - d.sub.10)/d.sub.50 -- --
0.34 -- -- -- (d.sub.90 - d.sub.10)/d.sub.50 -- -- 0.76 -- -- --
Diameter (cm) -- -- 4.95 -- -- -- Height (cm) -- -- 15.24 -- -- --
Cells per square inch -- -- 191 -- -- -- Wall Thickness (10.sup.-3
in) -- -- 14.0 -- -- -- Mass (g) -- -- 211.8 -- -- -- Approx.
Filter Bulk Density (g/cm.sup.3) -- -- 0.721 -- -- -- Pressure drop
at 0 g/L, 26.25 scfm (kPa) -- -- 1.87 -- -- -- Pressure drop at 5
g/L, 26.25 scfm (kPa) -- -- 4.51 -- -- --
[0076] TABLE-US-00021 TABLE 21 Example Number 82 83 84 85 86 87 88
% Al.sub.2TiO.sub.5 80 80 80 80 80 80 80 % Mullite 20 20 20 20 20
20 20 Weight Percent Y.sub.2O.sub.3 2.00 2.00 2.00 2.00 2.00 2.00
2.00 Alumina C 41.48 41.48 41.48 41.48 41.48 41.48 41.48 Aluminum
hydroxide A 20.00 20.00 20.00 20.00 20.00 20.00 20.00 Titania A
33.27 33.27 33.27 33.27 33.27 33.27 33.27 Quartz A 5.25 5.25 5.25
5.25 5.25 5.25 5.25 Graphite A 25.00 25.00 25.00 25.00 25.00 25.00
25.00 MPS Alumina sources 9.8 9.8 9.8 9.8 9.8 9.8 9.8 MPS Titania
source 0.5 0.5 0.5 0.5 0.5 0.5 0.5 MPS Quartz 3.7 3.7 3.7 3.7 3.7
3.7 3.7 MPS All Inorganic Raw Materials 6.4 6.4 6.4 6.4 6.4 6.4 6.4
Firing and Properties Firing Temperature (.degree. C.) 1415 1435
1455 1465 1475 1475 1435 Hold Time (hours) 8 6 6 4 6 6 6 Kiln Type
(E = electric, G = gas) E G G E E G E CTE (RT-1000.degree. C.) -0.5
-3.5 0.7 -5.1 -4.3 -0.3 -- % Porosity 48.3 48.7 48.5 46.5 46.9 49.9
-- d.sub.50 9.7 9.5 10.5 10.2 10.5 10.7 -- d.sub.10 -- -- -- -- --
-- -- d.sub.90 -- -- -- -- -- -- -- (d.sub.50 - d.sub.10)/d.sub.50
-- -- -- -- -- -- -- (d.sub.90 - d.sub.10)/d.sub.50 -- -- -- -- --
-- -- Diameter (cm) -- -- -- 4.83 -- -- 4.89 Height (cm) -- -- --
15.30 -- -- 15.24 Cells per square inch -- -- -- 208 -- -- 203 Wall
Thickness (10.sup.-3 in) -- -- -- 13.6 -- -- 12.7 Mass (g) -- -- --
214.9 -- -- 207.2 Approx. Filter Bulk Density (g/cm.sup.3) -- -- --
0.767 -- -- 0.724 Pressure drop at 0 g/L, 26.25 scfm -- -- -- 2.02
-- -- 1.94 (kPa) Pressure drop at 5 g/L, 26.25 scfm -- -- -- 5.48
-- -- 4.86 (kPa)
[0077] TABLE-US-00022 TABLE 22 Example Number 89 90 91 92 93 %
Al.sub.2TiO.sub.5 70 70 70 70 70 % Mullite 30 30 30 30 30 Weight
Percent Y.sub.2O.sub.3 2.00 2.00 2.00 2.00 2.00 Alumina C 43.01
43.01 43.01 43.01 43.01 Aluminum hydroxide C 20.00 20.00 20.00
20.00 20.00 Titania A 29.12 29.12 29.12 29.12 29.12 Quartz C 7.87
7.87 7.87 7.87 7.87 Graphite A 25.00 25.00 25.00 25.00 25.00 MPS
Alumina sources 12.8 12.8 12.8 12.8 12.8 MPS Titania source 0.5 0.5
0.5 0.5 0.5 MPS Quartz 25.4 25.4 25.4 25.4 25.4 MPS All Inorganic
Raw Materials 10.2 10.2 10.2 10.2 10.2 Firing and Properties Firing
Temperature (.degree. C.) 1415 1435 1435 1455 1475 Hold Time
(hours) 8 6 6 6 6 Kiln Type (E = electric, G = gas) E G E G E CTE
(RT-1000.degree. C.) 6.5 4.1 5.1 3.9 3.6 % Porosity 47.8 51.8 49.3
50.5 48.4 d.sub.50 10.5 10.4 10.4 10.7 11.5 d.sub.10 -- -- 6.9 --
-- d.sub.90 -- -- 17.5 -- -- (d.sub.50 - d.sub.10)/d.sub.50 -- --
0.34 -- -- (d.sub.90 - d.sub.10)/d.sub.50 -- -- 0.97 -- -- Diameter
(cm) -- -- 4.91 4.96 -- Height (cm) -- -- 15.24 15.34 -- Cells per
square inch -- -- 202 194 -- Wall Thickness (10.sup.-3 in) -- --
13.6 14.1 -- Mass (g) -- -- 207.1 205.4 -- Approx. Filter Bulk
Density (g/cm.sup.3) -- -- 0.716 0.693 -- Pressure drop at 0 g/L,
26.25 scfm (kPa) -- -- 1.89 1.73 -- Pressure drop at 5 g/L, 26.25
scfm (kPa) -- -- 5.02 4.88 --
[0078] TABLE-US-00023 TABLE 23 Example Number 94 %
Al.sub.2TiO.sub.5 80 % Mullite 20 Weight Percent Y.sub.2O.sub.3
2.00 Alumina B 41.48 Aluminum hydroxide C 20.00 Titania A 33.27
Quartz B 5.25 Graphite A 25 MPS Alumina sources 12.9 MPS Titania
source 0.50 MPS Quartz 23.4 MPS All Inorganic Raw Materials 9.3
Firing and Properties Firing Temperature (.degree. C.) 1425 Hold
Time (hours) 10 % Porosity 48.8 d.sub.50 10.2 Pre- Post- Cycled
Cycled % Length Change -- +0.21% CTE (RT-1000.degree. C.) on rod
-2.2 -3.6 MOR rod (psi) 825 815
* * * * *