Resistors and compositions therefor

Abstract

Powder compositions for producing high resistivity resistors capable of withstanding high voltage surges without large changes in resistivity, said compositions comprising finely divided pyrochlore-related oxides, lead glasses and metal titanates. Alternately to comprising titanates, the compositions may comprise metal titanate precursors such as crystallizable glasses capable of forming metal titanates upon being heated or titanium oxide plus a glass which react to form metal titanates.

Description

BACKGROUND OF THE INVENTION

This invention relates to resistors, and more particularly, to film resistors capable of operating at high voltage, as well as compositions for making same.

Pyrochlore is a mineral of varying composition generally expressed as (Na,Ca)₂ (Nb,Ti)₂ (O,F)₇, but which approaches the simpler formulation NaCaNb₂ O₆ F. The structure of the mineral, established by characteristic X-ray reflections, has a cubic unit cell with dimensions of about 10.4 Angstroms and contains eight formula units of approximate composition A₂ B₂ X₆-7. The term pyrochlore is used interchangeably herein with the term pyrochlore-related oxide to mean oxides of the pyrochlore structure with the approximate formula A₂ B₂ O₆-7. Compounds of the pyrochlore-related (cubic) crystal structure are known to be useful as resistors. See, for example, Schubert U.S. Pat. No. 3,560,410, issued Feb. 2, 1971; Hoffman U.S. Pat. No. 3,553,109, issued Jan. 5, 1971; Bouchard U.S. Pat. No. 3,583,931, issued June 8, 1971; Popowich U.S. Pat. No. 3,630,969, issued Dec. 28, 1971; Bouchard U.S. Pat. No. 3,681,262, issued Aug. 1, 1972; and Bouchard U.S. Pat. No. 3,775,347, issued Nov. 27, 1973; each of which is incorporated by reference herein.

Such pyrochlore-based resistors have often been found to have deficiencies when compounded to achieve high resistivities. The high voltage handling capability of film resistors is important, since in certain demanding high voltage uses a resistor may operate at a voltage stress in the range 1000-3000 volts/inch (40-120 volts/mm), and may be exposed to brief (less than one second duration) voltage surges up to 30 kilovolts/inch. As a result of such a voltage surge, most resistors exhibit a permanent change in resistance of up to 50% of their pre-surge lower operating voltage resistance. Resistors are needed which can undergo high voltage surges without undergoing such large changes in resistivity.

The resistivity of presently available high resistivity resistors is normally quite dependent on the concentration of the conductive phase. Therefore, resistor compositions less dependent upon variations in concentration of the conductive phase are needed.

Thus, improved resistor compositions and resistors are needed where high resistivity (1 to 10 megohm per square) are desired, for example, in high voltage applications such as voltage divider networks, focus potentiometers, and other electrical networks.

SUMMARY OF THE INVENTION

This invention is film resistors adherent to a dielectric substrate. The resistor is adherent to the substrate by virtue of having been printed thereon using typical screen of stencil techniques, followed by firing to sinter or coalesce the deposited inorganic powders to produce a coherent, electrically continuous pattern on the substrate. The resistors comprise a conductive phase of particles of (1) pyrochlore-related oxides having the general formula A₂ B₂ O₆-7 and metal titanates; each of these types of crystalline particles are dispersed in a matrix of lead-containing glass. The glass contains at least 5 weight percent lead oxide dissolved therein. The resistors comprise about 5-15 weight percent of said metal titanate and preferably 10-50 weight percent of pyrochlore-related oxide, the remainder of the resistor being the aforementioned lead oxide containing glass.

The metal titanate preferably comprises a multivalent cation in addition to a titanium/oxygen titanate anion. Preferred titanate anions include (TiO₃)²-. Preferred pyrochlores are lead ruthenate, bismuth ruthenate and lead iridate. It is preferred that the metal titanate comprise barium titanate, lead titanate and/or lead zirconate titanate.

Also a part of this invention are powder compositions useful for forming such resistors on dielectric substrates using thick-film techniques. The power compositions comprise the aforementioned pyrochlore-related oxides and one or more of the following titanium materials:

1. a metal titanate and a glass comprising at least 10 weight percent PbO dissolved therein, Where the metal titanate is to be provided in the resistor by in situ crystallization of the glass during firing, a crystallizable TiO₂ -containing glass is used in the desired quantities. The glass normally contains at least 5% TiO₂ dissolved therein, and also a metal oxide. Exemplary of such crystallizable glasses are those of Stookey U.S. Pat. No. 2,920,971, issued Jan. 12, 1960. Useful crystallizable glasses also include lead titanium silicates and aluminosilicates of

.Badd.50-70% PbO.Baddend.

.Badd.5-15% TiO₂ .Baddend.

.Badd.15-35% SiO₂ .Baddend.

.Badd.0-15% Al₂ O₃ .Baddend.

Optimum crystallizable glasses 60% PbO, 7% TiO₂, 32% SiO₂ and 1% Al₂ O₃.

Where the powder composition contains neither does not contain preformed metal titanates nor a crystallizable TiO₂ -containing glass, it may comprise comprises a mixture of titanium oxide and a glass which reacts therewith (or firing) to form metal titanates. Such glasses comprise, dissolved therein, at least 10% PbO, preferably 50-80% PbO, and optionally other preferred metal oxides such as BaO, Bi₂ O₃, etc. By titanium oxide is meant TiO₂ or any of the well-known oxygen deficient titanium oxide such as those mentioned by A. F. Wells in Structural Inorganic Chemistry, Oxford, Clarendon Press, 3rd Edition, 1962, p. 475. TiO₂ is preferred.

The relative amounts of pyrochlore and glass in the resistors and resistor compositions of this invention are selected according to generally known principles dependent upon the desired resultant properties. Generally, for these high resistivity resistors the amount of pyrochlore in the resistors and in the resistor compositions (on a solids basis) will be 10-50%, preferably 15-45%. The amount of glass in the resistors, and in resistor compositions wherein the titanates are not to be formed in situ, will be the difference between total weight of pyrochlore (10-50%) and titanate (5-15%) and 100%, or 35-85% glass.

Optimum compositions according to this invention are of 7.3% BaTiO₃, 21.7% Pb₂ Ru₂ O₆ and 71% lead aluminosilicate glass.

The resistor (powder) compositions of the present invention may be printed on any conventional dielectric substrate (e.g., alumina, ceria, etc.) using thick-film techniques. By "thick film" is meant films obtained by printing dispersions of powders (usually in an inert liquid vehicle) on a substrate using techniques such as screen and stencil printing, as opposed to the so-called "thin" films deposited by evaporation or sputtering. Thick-film technology is discussed generally in Handbook of Materials and Processes for Electronics, C. A. Harper, Editor, McGraw-Hill, New York, 1970, Chapter 11.

The powders are sufficiently finely divided to be used in conventional screen or stencil printing operations and to facilitate sintering. The compositions are prepared from the solids and vehicles by mechanical mixing and printed as a film on ceramic dielectric substrates in the conventional manner. Any inert liquid may be used as the vehicle. Water or any one of various organic liquids, with or without thickening and/or stabilizing agents and/or other common additives, may be used as the vehicle. Exemplary of the organic liquids which can be used are the aliphatic alcohols; esters of such alcohols, for example, the acetates and propionates; terpenes such as pine oil, terpineol and the like; solutions of resins such as the polymethacrylates of lower alcohols, or solutions of ethylcellulose, in solvents such as pine oil and the monobutyl ether of ethylene glycol monoacetate. The vehicle may contain or be composed of volatile liquids to promote fast setting after application to the substrate.

The ratio of inert liquid vehicle to solids in the dispersions may vary considerably and depends upon the manner in which the dispersion is to be applied and the kind of vehicle used. Generally, from 0.2 to 20 parts by weight of solids per part by weight of vehicle will be used to produce a dispersion of the desired consistency. Preferred dispersions contain 20-70% vehicle.

The printed pattern is normally dried at 100°-150°Cto remove solvent. Firing or sintering of the powder compositions of the present invention normally occurs at temperatures in the range 750°-950°C, for 5 minutes to 2 hours, depending on the particular compositions employed and the desired degree of sintering, as will be known to those skilled in the art. Generally, shorter firing times may be employed at higher temperatures. As one skilled in the art knows when crystallizable glasses are used, heating should be sufficiently long to permit nucleation and crystal formation.

EXAMPLES

The following examples are presented to illustrate the invention. In the examples and elsewhere in the specification and claims all parts, percentages, and ratios are by weight, unless otherwise stated.

The high voltage handling capability of film resistors was evaluated by subjecting the resistors to stress (stressed) at voltage gradients up to 50 kilovolts/inch (127 kv/cm) for 15 seconds. Resistance before stress (Ro) was compared with resistance after stress (R_ref), each measured at low stress (typically 500 volts/mm.) and the percent permanent change in resistance was defined as ##EQU1##

The resistors were prepared as follows. A dispersion or paste of the seven parts of the solids indicated below in three parts an inert liquid vehicle (1/9 ethylcellulose/terpineol) was prepared by conventional roll-milling techniques. The paste was printed on Alsimag 614 alumina substrates bearing prefired Pd/Ag (1/2.5) electrode terminations, using a 200-mesh screen to print 25 mm square patterns. The pattern was dried at 150°C in an air oven for 15 minutes (to a thickness of about 25 microns) and then fired in a belt furnace to a maximum temperature of about 850°C (about 8 minutes at peak); total furnace residence time was about 45-60 minutes. The dried print about 17 microns thick.

The glasses used in the Examples are designated A, B and C therein, and are identified in Table I.

TABLE 1
______________________________________
GLASSES USED IN EXAMPLES (WT. %)
Glass A        Glass B      Glass C
______________________________________
65.0% PbO      32.0% PbO    60.0% PbO
34.0% SiO 2
27.0% SiO2
32.0% SiO2
--1.0% Al2 O3
11.0% Al2 O3
1.0% Al2 O3
12.0% TiO2
7.0% TiO2
10.0% ZnO
8.0% BaO
______________________________________

The inorganic materials used herein, and their relative proportions, are set forth in Tables II-V. The powders were each finely divided (by conventional milling techniques), the surface areas being for pyrochlore-related oxides, 9.0-14.0 m.² /g., for titanate powders 4.0-5.0 m.² /g., for glasses 6.0-8.0 m.² /g., and for TiO₂ 9 m.² /g.

EXAMPLES 1-3; SHOWINGS A-C (TABLE II)

In Examples 1-3 and Showings A and C (Table II) the conductive phase and glass were the same. In examples 1-3, barium titanate (BaTiO₃) were added. Each was stressed, as indicated in Table II, at 700 or 1000 volts/mm. The Examples comprising barium titanate were found to exhibit a percent permanent change in resistivity which was about an order of magnitude less than that observed where barium titanate was absent.

To emphasize that not any crystalline phase will function to reduce change in resistivity, a crystallizing glass which forms crystals other than titanate was employed in Showing B. the major crystalline phase formed in the glass after firing was BaAl₂ Si₂ O₈ ; a minor amount (probably much less than 3% of the total composition) of Al₂ TiO₅ may have been formed. The percent permanent change in resistivity was similar to that of Showings A and C.

EXAMPLES 4-9; SHOWING D (TABLE III)

Resistors of higher sheet resistivity than those of Table II were examined here. The same conductive phase (lead ruthenate) was used throughout, but the titanate additive was varied; the latter was provided to the fired resistor by including a titanate powder to the printing paste (barium titanate at various levels in Examples 4 and 5; lead titanate in Example 6); by adding lead titanate zirconate powder to the paste (Example 7); by adding TiO₂ powder to paste, which reacted with the glass to form a titanate on firing (Example 8); or by using a glass which partially crystallizes to lead titanate on firing (Example 9).

Showing D used a composition not of this invention, lead ruthenate and the noncrystallizing glass of Examples 4-8, but no titanates or titanate-formers; however, the sheet resistivity was similar to that of Examples 4-9. Table III shows compositions and results.

BaTiO₃ additions of 7.3% and 14.3% (Examples 4 and 5, respectively) to compositions containing Pb₂ Ru₂ O₆ and lead aluminosilicate glass result in nearly two order of magnitude decrease of the permanent resistance change, after voltage stressing at 1000 v/mm, over Comparative Showing D without BaTiO₃.

Examples 6 and 7 emphasize that improved voltage properties may also be obtained with additions of other titanate-based dielectric, namely PbTiO₃ and PZT.

In Example 8, TiO₂ was added to a Pb₂ Ru₂ O₆ /lead aluminosilicate composition. X-ray diffraction data for the fired resistors revealed that the TiO₂ had combined during firing with the lead-based glass to form PbTiO₃.

TABLE II
__________________________________________________________________________
V
R (Sheet
(Voltage
ΔRperm.
Conductive Phase
Glass Phase
BaTiO2
Resistivity)
Stress)
(% Perm. Resist.
(wt. %)         (wt. %) (wt. %)
(kohm/square)
(volts/mm.)
Change)
__________________________________________________________________________
Example 1
Pb2 Ru2 O6 (35.2)
Type A (57.7)
7.1  110      700    1.5
Example 2
Pb2 Ru2 O6 (28.6)
Type A (64.3)
7.1  350     1000    2.0
Example 3
Pb2 Ru2 O6 (24.3)
Type A (68.6)
7.1  875     1000    0.6
Showing A
Pb2 Ru2 O6 (21.0)
Type A (79.0)
--   123      700   14.0
Showing B
Pb2 Ru2 O6 (23.6)
Type B (76.4)
--   102      700   12.0
Showing C
Pb2 Ru2 O6 (19.5)
Type A (80.5)
0.0  523     1000   12.0
__________________________________________________________________________

The voltage properties were superior to those of Comparative Showing D.

In Example 9, PbTiO₃ was introduced into the final resistor composition using a crystallizable glass. Again the permanent resistance change after voltage stressing is significantly smaller than for Comparative Showing D.

TABLE III
__________________________________________________________________________
V
R (Sheet (Voltage
ΔRperm
Conductive Phase
Glass Phase
Additive
Resistivity)
Stress)
(% Perm. Resist.
(wt. %)         (wt. %)
(wt. %)
(Megohm/square)
(volts/mm)
Change)
__________________________________________________________________________
Showing D
Pb2 Ru2 O6 (17.4)
Type A (82.6)
--    1.00     1000  25.0
Example 4
Pb2 Ru2 O6 (21.7)
Type A (71.0)
BaTiO3 (7.3)
1.48     "     0.3
Example 5
Pb2 Ru2 O6 (21.4)
Type A (64.3)
BaTiO3 (14.3)
2.58     "     0.3
Example 6
Pb2 Ru2 O6 (29.0)
Type A (63.8)
PbTiO3 (7.2)
1.70     "     1.7
Example 7
Pb2 Ru2 O6 (29.0)
Type A (63.8)
PZT* (7.2)
1.17     "     3.0
Example 8
Pb2 Ru2 O6 (29.0)
Type A (63.8)
TiO2 (7.2)
1.06     "     0.9
Example 9
Pb2 Ru2 O6 (16.1)
Type C (83.9)
--    2.19     "     1.0
__________________________________________________________________________
*PZT or lead zirconate titanate has the approximate composition Pb1.
Zr9.97 Ti 9.42 O3.

TABLE IV
__________________________________________________________________________
V
R(Sheet   (Voltage
ΔRperm.
Conductive Phase
Glass Phase
BaTiO3
Resistivity)
Stress)
(% Perm. Resist.
(wt. %)         (wt. %) (wt. %)
(megohm/square)
(volt/mm)
Change)
__________________________________________________________________________
Showing E
Bi2 Ru2 O2 (21.0)
Type A (79.0)
--   1.67      1000  38.0
Example 10
Bi2 Ru2 O7 (29.4)
Type A (63.2)
7.4  1.84      "      0.8
Showing F
Pb2 Ir2 O6 (36.2)
Type A (63.8)
--   1.55      200   55.0
Example 11
Pb2 Ir2 O6 (41.1)
Type A (53.4)
5.5  10.92     200    0.4
__________________________________________________________________________

EXAMPLES 10 and 11; SHOWINGS E AND F (TABLE IV)

The effectiveness of titanates in reducing permanent change in resistivity after high voltage stress using other pyrochlore-related oxides is illustrated by these Examples and Showings. Compositions and data are set forth in Table IV.

EXAMPLES 12, 13, 14, and 15; SHOWINGS G AND H (TABLE V)

Showings G and H emphasize the major impediment to easy manufacture of high resistivity compositions. Only a very small difference in the weight percent conductive phase (1.3%) causes a change in resistance of one order of magnitude (1 to 10 megohms per square). This property is responsible for lack of reproducibility in the manufacture of high resistivity compositions.

In Examples 12 and 13, additions of BaTiO₃ show that a much greater difference (9.8%) in the conductive phase concentration is possible for sheet resistivities in that range. Hence, barium titanate additions make the high resistivity compositions much less sensitive to pyrochlore concentration.

In Examples 14 and 15, where a crystallizable glass is used, the conductive phase increment is 8.7% for 1 megohm/square and 10 megohms/square sheet resistivities, again a substantial improvement over that in Showings G and H.

TABLE V
__________________________________________________________________________
R (Sheet
Conductive Phase
Glass Phase
BaTiO3
Resistivity)
Change in Wt. %
(wt. %)         (wt. %) (wt. %)
(megohm/square)
Conductive Phase
__________________________________________________________________________
Showing
Pb2 Ru2 O6 (18.4)
Type A (81.6)
--    1
1.3
Showing H
Pb2 Ru2 O6 (17.1)
Type A (82.9)
--   10
Example 12
Pb2 Ru2 O6 (41.2)
Type A (51.4)
7.4  1
9.8
Example 13
Pb2 Ru2 O6 (31.4)
Type A (61.2)
7.4  10
Example 14
Pb2 Ru2 O6 (42.0)
Type C (58.0)
--   1
8.7
Example 15
Pb2 Ru2 O6 (33.3)
Type C (66.7)
--   10
__________________________________________________________________________

Showings J, K, and L

The unique effect of titanates in enhancing voltage-withstanding ability is illustrated by these Showings, which use bismuth stannate, (Bi)₂ (SnO₃)₃ ; lead zirconate, PbZrO₃ ; and lead niobate, PbNb₂ O₆. The composition and data are:

Showing J

Pb₂ Ru₂ O₆, 29.0%

Type A Glass, 63.8%

Bi₂ (SnO₃)₃, 7.2%

R, 0.94 megohm/square

Voltage stress, 1000 volts/mm

ΔR_perm., 14.0%

Showing K

Pb₂ Ru₂ O₆, 29.4%

Type A Glass, 63.2%

PbZrO₃, 7.4%

R, 187 Kohms/square

Voltage stress, 700 volts/mm

ΔR_perm., 23%

Showing L

Pb₂ Ru₂ O₆, 29.0%

Type A Glass, 63.8%

PbNb₂ O₆, 7.2%

R, 200 Kohms/square

Voltage stress, 700 volts/mm

ΔR_perm., 23%

Claims

1. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said pyrochlore-related oxides being selected from among those of formula

(M_x Bi₂-x)(M'_y Ru_z-y)O₇-z,

wherein

M is at least one metal selected from the group consisting of yttrium, indium, cadmium, lead, and the rare earth metals of atomic number 57-71, inclusive;

M' is at least one metal selected from the group consisting of platinum, titanium, tin, chromium, rhodium, iridium, zirconium, antimony, and germanium;

x is a number in the range 0-2;

y is a number in the range 0-2; and

z is a number in the range 0-1, being at least equal to about x/2 when M is a divalent metal; those of the formula

M_x M'₂-x M"₂ O₇-z,

wherein

M is at leat one of Ag or Cu;

M' is Bi or a mixture of at least one half Bi plus up to one half of one or more cations from among

a. bivalent Cd or Pb and

b. trivalent Y, Tl, In, and rare earth metals of atomic number 57-71, inclusive;

M" is at least one of

a. Ru,

b. Ir, and

c. a mixture of at least three-fourths of at least one of Ru and Ir and up to one-fourth of at least one of Pt, Ti, and Rh;

x is in the range 0.10 to 0.60, and

z is in the range 0.10 to 1.0, and is equivalent to the sum of monovalent cations M and half of divalent cations in said formula; and mixtures thereof resistor being a sintered composition of claim 19.

2. A resistor according to claim 1 comprising 5-15 weight percent of said metal titanate.

3. A resistor according to claim 1 wherein said glass contains at least 5 weight percent PbO dissolved therein.

4. A resistor according to claim 2 wherein said glass contains at least 5 weight percent PbO dissolved therein.

5. A film resistor according to claim 1 wherein said metal titanate comprises a multivalent cation.

6. A film resistor according to claim 2 wherein said metal titanate comprises a multivalent cation.

7. A film resistor according to claim 1 where the anion in said titanate is (TiO₃)²-.

8. A film resistor according to claim 2 where the anion in said titanate is (TiO₃)²-.

9. A film resistor according to claim 5 where the anion in said titanate is (TiO₃)²-.

10. A film resistor according to claim 6 where the anion in said titanate is (TiO₃)²-.

11. A film resistor according to claim 1 comprising 10-50 weight percent pyrochlore-related oxide.

12. A film resistor according to claim 2 comprising 10-50 weight percent pyrochlore-related oxide.

13. A resistor according to claim 1 wherein the pyrochlore-related oxide is Pb₂ Ru₂ O₆.

14. A film resistor according to claim 1 wherein said pyrochlore-related oxide is Bi₂ Ru₂ O₇.

15. A film resistor according to claim 1 wherein said pyrochlore-related oxide is Pb₂ Ir₂ O₆.

16. A resistor according to claim 1

wherein said titanate comprises barium titanate.

17. A resistor according to claim 1 wherein said titanate comprises lead titanate.

18. A resistor according to claim 1 wherein said titanate comprises

lead zirconate titanate. 19. A powder composition useful for forming film resistors on a dielectric substrate, the powder comprising pyrochlore-related oxides and a titanium material selected from the class consisting of

1. a metal titanate and a glass comprising at least 10 weight percent PbO dissolved therein, and

2. one or more glasses at least one of which comprises at least 5 weight percent titanium dioxide dissolved therein and a metal oxide and is capable of crystallization to form a metal titanate upon being heated and3.titanium oxide and a glass comprising at least 10 weight percent PbO dissolved therein,

said pyrochlore-related oxides being selected from among those of the formula

(M_x Bi₂-x)(M'_y Ru₂-y)O₇-z,

wherein

M is at least one metal selected from the group consisting of yttrium, indium, cadmium, lead, and the rare earth metals of atomic number 57-71, inclusive;

M' is at least one metal selected from the group consisting of platinum, titanium, tin, chromium, rhodium, iridium, zirconium, antimony, and germanium,

x is a number in the range 0-2;

y is a number in the range 0-2; and

z is a number in the range 0-1, being at least equal to about x/2 when M is a divalent metal; those of the formula

M_x M'₂-x M"₂ O₇-7, wherein

M is at least one of Ag or Cu;

M' is Bi or a mixture of at least one half Bi plus up to one half of one or more cations from among

a. bivalent Cd or Pb and

b. trivalent Y, Tl, In, and rare earth metals of atomic number 57-71, inclusive;

M" is at least one of

a. Ru,

b. Ir, and

c. a mixture of at least three-fourths of at least one of Ru and Ir and up to one-fourth of at least one of Pt, Ti, and Rh;

x is in the range 0.10 to 0.60, and

z is in the range 0.10 to 1.0, and is equivalent to the sum of monovalent cations M and half of divalent cations in said formula; and mixtures

thereof. 20. A composition according to claim 19 comprising titanium

material (1). 21. A composition according to claim 20 wherein said glass

comprises at least 50% PbO dissolved therein. 22. A composition according to claim 19 comprising titanium material (2).

23. A composition according to claim 22 wherein said glass comprises 50-70% PbO, 5-15% TiO₂, 15-35% SiO₂ and 0-15% Al₂ O₃.

24. A composition according to claim 19 comprising titanium material (3).

A composition according to claim 24 22 wherein

said glass comprises at least 50% PbO dissolved therein. 26. A composition according to claim 24 22 wherein said titanium oxide

is TiO₂. 27. A composition according to claim 25 wherein said

titanium oxide is TiO₂. 28. A powder composition according to claim 20 comprising sufficient titanium material to produce an amount of metal titanate equal to 5-15 weight percent of the total composition weight.

A powder composition according to claim 22 comprising sufficient titanium material to produce an amount of metal titanate equal to 5-15

weight percent of the total composition weight. 30. A powder composition according to claim 24 27 comprising sufficient titanium material to produce an amount of metal titanate equal to 5-15

weight percent of the total composition weight. 31. A powder composition according to claim 19 wherein said pyrochlore-related oxide is Pb₂

Ru₂ O₆. 32. A powder composition according to claim 19 wherein

said pyrochlore-related oxide is Bi₂ Ru₂ O₇. 33. A powder composition according to claim 19 wherein said pyrochlore-related oxide is

Pb₂ Ir₂ O₆. 34. A powder composition according to claim 20

wherein said pyrochlore-related oxide is Pb₂ Ru₂ O₆. 35. A powder composition according to claim 20 wherein said pyrochlore-related

oxide is Bi₂ Ru₂ O₇. 36. A powder composition according to claim 20 wherein said pyrochlore-related oxide is Pb₂ Ir₂

O₆. 37. A powder composition according to claim 22 wherein said

pyrochlore-related oxide is Pb₂ Ru₂ O₆. 38. A powder composition according to claim 22 wherein said pyrochlore-related oxide is

Bi₂ Ru₂ O₇. 39. A powder composition according to claim 22

wherein said pyrochlore-related oxide is Pb₂ Ir₂ O₆. 40. A powder composition according to claim 24 27 wherein

said pyrochlore-related oxide is Pb₂ Ru₂ O₆. 41. A powder composition according to claim 24 27 wherein said

pyrochlore-related oxide is Bi₂ Ru₂ O₇. 42. A powder composition according to claim 24 27 wherein said

pyrochlore-related oxide is Pb₂ Ir₂ O₆. 43. A composition according to claim 20 wherein the metal in said metal titanate is

multivalent. 44. A composition according to claim 22 wherein the metal in

said metal oxide is multivalent. 45. A composition according to claim 19

comprising 10-50 weight percent pyrochlore-related oxide. 46. A composition according to claim 20 comprising 10-50 weight percent

pyrochlore-related oxide. 47. A composition according to claim 22

comprising 10-50 weight percent pyrochlore-related oxide. 48. A composition according to claim 24 27 comprising 10-50

weight percent pyrochlore-related oxide. 49. The composition of claim 19

dispersed in an inert liquid vehicle. 50. The composition of claim 20

dispersed in an inert liquid vehicle. 51. The composition of claim 22

dispersed in an inert liquid vehicle. 52. The composition of claim

24 27 dispersed in an inert liquid vehicle. 53. The

composition of claim 45 dispersed in an inert liquid vehicle. 54. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 20. 55. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 21. 56. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 22. 57. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 25. 58. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 26. 59. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said

resistor being a sintered composition of claim 27. 60. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 28. 61. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 29. 62. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 30. 63. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 31. 64. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 32. 65. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said

resistor being a sintered composition of claim 33. 66. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 45. 67. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 46. 68. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 47. 69. A film resistor adherent to a dielectric substrate wherein the resistor comprises a conductive phase of crystalline particles of (1) pyrochlore-related oxides and (2) metal titanates, each dispersed in a matrix of a lead containing glass, said resistor being a sintered composition of claim 48.