Ex Parte Venigalla

Board of Patent Appeals and Interferences

Mar 4, 2010

11031099 (B.P.A.I. Mar. 4, 2010)

UNITED STATES PATENT AND TRADEMARK OFFICE
____________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
____________

Ex parte SRIDHAR VENIGALLA
____________

Appeal 2009-012324
Application 11/031,099
Technology Center 1700
____________

Decided: March 4, 2010
____________

Before EDWARD C. KIMLIN, CHUNG K. PAK, and TERRY J. OWENS,
Administrative Patent Judges.

KIMLIN, Administrative Patent Judge.

DECISION ON APPEAL

This is an appeal from the final rejection of claims 1, 3-5, 8, 10-12,
16, 18-20 and 31-39. Claim 1 is illustrative:
1. A method to passivate a powder comprising
passivating said powder with a gas having at least 25 wt. %
oxygen present to form a passivated powder, wherein said
powder is tantalum powder, niobium powder, or niobium
suboxide powder, and wherein said powder has a BET surface
Appeal 2009-012324
Application 11/031,099

2
area of from 0.2 to 40 m2/g, and a capacitance capability of
from 10,000 to 400,000 CV/g.

The Examiner relies upon the following references as evidence of
obviousness:

Rao 2002/0088507 A1 Jul. 11, 2002
Nagato 6,430,026 B1 Aug. 6, 2002

Appellant’s claimed invention is directed to a method for passivating
a powder. The method entails passivating powders of tantalum, niobium or
niobium suboxide with a gas having at least 25 wt. % oxygen. According to
Appellant, it was conventional in the art to passivate high surface area
capacitor grade powders by exposure to atmospheric air which contains only
20 wt. % oxygen. The nitrogen in the air was trapped between the powder
particles and hindered passivation. Multiple vent/evacuation cycles were
needed to passivate such particles. Appellant submits that “the methods of
the present invention can be accomplished without any evacuation cycles”
(Prin. Br. 12, first para.).
Appealed claims 1, 3-5, 8, 10-12, 16, 18-20 and 31-39 stand rejected
under 35 U.S.C. § 103(a) as being upatentable over Nagato in view of Rao.
We have thoroughly reviewed the respective positions advanced by
Appellant and the Examiner. In so doing, we find ourselves in agreement
with Appellant that the Examiner has failed to establish a prima facie case of
obviousness for the claimed subject matter. Accordingly, we will not sustain
the Examiner’s rejection.
A principal argument advanced by Appellant is that Nagato, while
teaching the oxygen passivation of tantalum metal and niobium metal in the
form of a foil, sheet, bar or sintered body, does not teach or suggest
Appeal 2009-012324
Application 11/031,099

3
passivating powders of such metals, let alone powders having the claimed
surface area and capacitance capabilities. In response to Appellant’s
argument, the Examiner states that Nagato “also defines the shape of the
metal or alloy as powders” (col. 4, ll. 31-34) (Ans. 5, second para.).
However, as emphasized by Appellant, the relevant portion of Nagato reads
as follows:
The metal or alloy may be partially nitrided, for example,
by a method of heating it in nitrogen at the stage of a
prescribed form, at the stage of powder, at the stage after the
molding or at the stage after the sintering. (col. 4, ll. 31-35,
emphasis added).

Manifestly, the portion of Nagato cited by the Examiner refers to
heating the powder in nitrogen, not oxygen. The Examiner cites no portion
of Nagato that teaches or suggests exposing the metal powder to an oxygen
atmosphere. Rao, cited by the Examiner for disclosing tantalum and
niobium powders having the claimed surface area and capacitance capacity,
does not remedy the basic deficiency of Nagato. Also, we note that the
Examiner makes no argument that it would been obvious to modify the
passivation process of the admitted prior art, which uses a gas comprising 20
% oxygen, by increasing the oxygen concentration of the gas to at least the
claimed 25 wt. %.
Appeal 2009-012324
Application 11/031,099

4

Accordingly, since the Examiner’s legal conclusion of obviousness
lacks the requisite factual support, we are constrained to reverse the
Examiner’s rejection.

REVERSED

kmm

MARTHA ANN FINNEGAN, ESQ.
CABOT CORPORATION
BILLERICA TECHNICAL CENTER
157 CONCORD ROAD
BILLERICA, MA 01821-7001