PTAB

IPR2015-00398

CeramTec GmbH v. CeraMedic LLC

Log In
Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Sintered Al2O3 Material, Process for Its Production and Use of the Material
  • Brief Description: The ’584 patent discloses methods for producing high-density, fine-grained sintered α-Al2O3 (alumina) ceramic materials. The claimed process generally involves dispersing high-purity alumina powder in an aqueous solution using at least two distinct dispersing methods, treating the resulting mixture to form a shaped, unsintered body, and subsequently heating and sintering that body.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1, 4, 5, 30, 33, 34, 52, 53 over Lin

  • Prior Art Relied Upon: Lin (Jiang Tsair Lin, Temperature History and Microstructure of Alumina (May 1992) (Ph.D. Dissertation)).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Lin, a Ph.D. dissertation on preparing sintered alumina materials, discloses every limitation of independent claims 1 and 52. Lin allegedly used a high-purity (99.995%) α-Al2O3 powder with a mean particle size (d50 of 0.18 µm) and surface area (10.4 m²/g) that meets the requirements of claims 1 and 4. Petitioner asserted Lin taught applying two different dispersing methods in series, as required by claim 30: an initial dispersion of the powder in deionized water, followed by the application of an ultrasonic probe to the suspension to break down soft agglomerates. Lin then treated this mixture via slip casting to form a shaped, unsintered body with a relative density of 61-63%, satisfying the claimed ≥55% density limitation. Finally, Lin disclosed heating the body to burn off organics and sintering it in air (pressureless sintering, per claim 5) to create a sintered material.

Ground 2: Obviousness of Claims 3, 19, 20, 23, 31 over Lin in view of Sonuparlak

  • Prior Art Relied Upon: Lin (a 1992 PhD dissertation) and Sonuparlak (4,777,153).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground addressed claims requiring specific dispersing methods (e.g., stirring, ultrasound). While Lin disclosed two sequential dispersing methods, Sonuparlak explicitly taught using simultaneous stirring and ultrasonication to break up agglomerates in an alumina suspension.
    • Motivation to Combine: Petitioner argued a person of ordinary skill in the art (POSITA) would combine the teachings because both references address the same technical problem of preparing a well-dispersed alumina slurry for forming a ceramic body. A POSITA would have found it obvious to substitute Sonuparlak's well-known dispersing technique (simultaneous stirring and ultrasound) into Lin's general process.
    • Expectation of Success: The substitution was argued to be a simple replacement of one known element with another known element to achieve the predictable result of effective deagglomeration, a common goal in ceramics processing.

Ground 3: Obviousness of Claims 7, 11, 13, 32, 37 over Lin in view of Yeh

  • Prior Art Relied Upon: Lin (a 1992 PhD dissertation) and Yeh (Tsung-Shou Yeh, Effect of green microstructure on the densification and microstructural evolution of alumina (1989) (Ph.D. dissertation)).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground targeted claims reciting specific particle size distributions (d16, d50, and d84 values). Petitioner asserted that while Lin's starting powder likely met these criteria, Yeh explicitly disclosed preparing and using an alumina powder with the specific particle size distribution required by the claims. Yeh also taught a multi-step dispersion process involving stirring, ultrasonication, and mixing.
    • Motivation to Combine: A POSITA would have been motivated to substitute the powder or powder preparation methods from Yeh into the overall process taught by Lin. Both dissertations aim to produce high-quality sintered alumina, and it would have been obvious to use a powder with Yeh's well-characterized and desirable particle size distribution to optimize the process.
    • Expectation of Success: Petitioner contended that using Yeh's powder in Lin's process was a predictable combination, as a POSITA would expect that a starting material with a controlled particle size distribution would lead to a high-quality green body and sintered product.

Ground 4: Obviousness of Claim 35 over Lin in view of Yeh & Sacks and Mizuta

  • Prior Art Relied Upon: Lin (a 1992 PhD dissertation), Yeh & Sacks (a 1988 journal article), and Mizuta (a 1992 journal article).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground targeted claim 35, which requires the "treating" step to comprise pressure filtration in a specific range. Lin taught forming a body by slip casting. Yeh & Sacks taught that for fine powders, slow casting rates can be enhanced by applying pressure during consolidation (i.e., pressure filtration). Mizuta provided a specific, enabling example, teaching the use of pressure filtration at 0.3 MPa (within the claimed 0.3-20 MPa range) to accelerate the consolidation rate.
    • Motivation to Combine: A POSITA would combine these references to solve the known problem of slow consolidation rates associated with the fine powders used in Lin's slip casting process. Yeh & Sacks identified the problem and proposed the solution, and Mizuta provided a specific, proven working example of that solution.
    • Expectation of Success: The combination was presented as a straightforward application of a known technique to a known problem to achieve a predictable improvement (faster processing).

  • Additional Grounds: Petitioner asserted numerous other challenges, including anticipation of claims 7, 12, 13, and 37 by Yeh alone; obviousness over Lin alone (for claims 32 and 36); and various other obviousness combinations including DeLuca (4,647,477), Cannell (a 1990 book chapter), and Jones (a 1986 journal article) to teach elements such as the use of binders/plasticizers (Jones) or stirring and milling as dispersing methods (DeLuca and Cannell).

4. Key Claim Construction Positions

  • "dispersing a-Al2O3 powder … to create a mixture": Petitioner argued this phrase should be construed to mean causing alumina particles "to become or continue being distributed" in water. This construction is critical because it allows a second "dispersing method" (e.g., ultrasonication) to be applied to a powder that is already suspended in water, thereby satisfying the "two different dispersing methods" limitation.
  • "treating said mixture so as to create a shaped unsintered body": Petitioner argued this phrase covers both direct and indirect uses of the aqueous mixture. Direct use involves processes like slip casting. Indirect use, supported by the specification and prosecution history, involves an intermediate step, such as drying the mixture to form granules which are then pressed to form the shaped body. This construction is key to applying prior art that uses dry pressing techniques.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-5, 7-13, 15-17, 19-21, 23, 30-38, and 52-53 of the ’584 patent as unpatentable under 35 U.S.C. §§ 102 and 103.