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Researchers Submit Patent Application, "Sinter Bonded Porous Metallic Coatings", for Approval

July 29, 2014



By a News Reporter-Staff News Editor at Life Science Weekly -- From Washington, D.C., NewsRx journalists report that a patent application by the inventors Steele, James K. (Rockfall, CT); White, Wayne F. (Granby, CT); Romano, Alfred M. (Hartland, CT); Rubow, Kenneth L. (Avon, CT), filed on January 7, 2014, was made available online on July 17, 2014 (see also Biotechnology Companies).

The patent's assignee is Mott Corporation.

News editors obtained the following quote from the background information supplied by the inventors: "Disclosed herein is a method to form a porous metallic coating on a substrate. More particularly, a suspension of nanosize particles in a carrier fluid is deposited on the substrate and heated to evaporate the carrier fluid while sintering the particles to the substrate.

"There are numerous applications requiring a porous open cell structure including filtration and gas or liquid flow control. These structures are typically formed by compacting metallic or ceramic particles to form a green compact and then sintering to form a coherent porous structure. Particle size, compaction force, sintering time and sintering temperature all influence the pore size and the structure strength. When the pore size is relatively large, such as microsize (having an average diameter of one micron (.mu.m) or greater), the structure thickness relative to pore size is modest for sufficient strength to be handled and utilized in industrial applications. When the pore size is relatively small, such as nanosize (having an average diameter of less than one micron), the structure thickness is much greater than pore size for sufficient strength to be handled and utilized in industrial applications. As a result, the structure has high resistance to passing a gas or liquid through the long length, small diameter pores and there is a high pressure drop across the filter. Note that for this application, the diameter is to be measured along the longest axis passing from one side of a particle to the other side and also passing through the particle center.

"A number of patents disclose methods for depositing a porous coating on a substrate. U.S. Pat. No. 6,544,472 discloses a method for depositing a porous surface on an orthopedic implant. Metallic particles are suspended in a carrier fluid. The carrier fluid may contain water, gelatin (as a binder) and optionally glycerin (as a viscosity enhancer). Evaporation of the water results in the metallic particles being suspended in a gelatinous binder. Heating converts the gelatin to carbon and sinters the metallic particles to the substrate.

"U.S. Pat. No. 6,652,804 discloses a method for the manufacture of a thin openly porous metallic film. Metal particles with an average particle diameter between one micron and 50 microns are suspended in a carrier fluid having as a primary component an alcohol, such as ethanol or isopropanol, and a binder. This suspension is applied to a substrate and heated to evaporate the alcohol component. A green film of microparticles suspended in the binder is then removed from the substrate and heated to a temperature effective to decompose the binder and sinter the metallic particles.

"U.S. Pat. No. 6,709,622 discloses a porous structure formed by mechanical attrition of metal or ceramic particles to nanosize and then combining the nanosized particles with a binder, such as a mixture of polyethylene and paraffin wax to form a green part. The green part is then heated to a temperature effective to decompose the binder and sinter the particles.

"U.S. Pat. Nos. 6,544,472; 6,652,804; and 6,709,622 are all incorporated by reference in their entireties herein.

"In addition to the thickness constraint discussed above, the inclusion of a binder and optional viscosity enhancer may further increase the pressure drop across a structure. During sintering, the binder and viscosity enhancer decompose, typically to carbon. This carbonatious residue may in whole or in part block a significant number of pores necessitating a high pressure drop across the structure to support adequate flow.

"There remains, therefore, a need for a method to deposit a thin nano powder layer on a substrate that does not suffer from the disadvantages of the prior art."

As a supplement to the background information on this patent application, NewsRx correspondents also obtained the inventors' summary information for this patent application: "In accordance with an embodiment of the invention, there is provided a method for forming a porous coating on a substrate. This method includes the steps of (a) forming a suspension of sinterable particles in a carrier fluid; (b) maintaining the suspension by agitating the carrier fluid; applying a first coating of the suspension to the substrate; and (d) sintering the sinterable particles to the substrate. An optional step (e) is to repeat steps and (d) additional times as necessary to achieve desired thickness and performance. It is a feature of certain embodiments of the invention that a thin coating of a nano powder material may be deposited onto a substrate having micropores. A first advantage of this feature is that the microporous substrate provides strength and structure support and the nano powder layer may be quite thin. As a result, a nanoporous material which has sufficient strength for handling and industrial processes is provided. Since the nano powder layer is thin, the pressure drop across the layer is substantially less than conventional thicker nano powder structures.

"The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below. Other features, objects and advantages of the invention will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

"FIG. 1 illustrates in flow chart representation a method for depositing a porous coating in accordance with an embodiment of the invention.

"FIG. 2 schematically illustrates a system for depositing the porous coating formed in accordance with an embodiment of the invention.

"FIG. 3 schematically illustrates a system for depositing the porous coating formed in accordance with a second embodiment of the invention.

"FIG. 4 schematically illustrates a system for depositing the porous coating on a tube in accordance with an embodiment of the invention.

"FIG. 5 schematically illustrates a system for depositing the porous coating on a tube in accordance with a second embodiment of the invention.

"FIG. 6 illustrates a porous tube suitable for gas flow regulation or filtration having a porous coating in accordance with an embodiment of the invention.

"FIG. 7 is a scanning electron micrograph of a surface of the porous coating formed in accordance with an embodiment of the invention.

"FIG. 8 is a scanning electron micrograph of a cross section of the porous coating of FIG. 4.

"FIG. 9 graphically illustrates the effect of successive layers of the porous coating of FIG. 4 on the gas flux.

"FIG. 10 illustrates a fuel cell component having a porous coating in accordance with an embodiment of the invention.

"FIG. 11 illustrates a frit for use in a liquid chromatography column having a porous coating in accordance with an embodiment of the invention.

"FIG. 12 illustrates a catalytic surface suitable for an industrial catalytic converter having a porous coating in accordance with an embodiment of the invention.

"FIG. 13 illustrates an adhesively bonded composite having a porous coating effective to enhance adhesion in accordance with an embodiment of the invention.

"FIG. 14 graphically illustrates isopropyl alcohol (IPA) liquid flow through 47 mm disk assemblies in accordance with Example 8.

"FIG. 15 graphically illustrates nitrogen flow through 47 mm disk assemblies in accordance with Example 8.

"FIGS. 16A and 16B are photomicrographs of a Media Grade 2 substrate coated with stainless steel nano particles by the process of FIG. 3.

"FIGS. 17A and 17B are photomicrographs of a tubular Media Grade 2 substrate coated with stainless steel nano particles by the process of FIG. 4.

"FIG. 18 graphically illustrates nitrogen flow through 0.5 inch OD coated tubes in accordance with Example 11.

"FIG. 19 graphically illustrates IPA liquid flow through 0.5 inch OD coated tubes in accordance with Example 11.

"FIG. 20 is a photograph of a bio-pharmaceutical vent filter in accordance with Example 12.

"FIG. 21 is a photograph of small parts for sterilizing grade filtration in accordance with Example 13.

"Like reference numbers and designations in the various drawings indicated like elements."

For additional information on this patent application, see: Steele, James K.; White, Wayne F.; Romano, Alfred M.; Rubow, Kenneth L. Sinter Bonded Porous Metallic Coatings. Filed January 7, 2014 and posted July 17, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=2525&p=51&f=G&l=50&d=PG01&S1=20140710.PD.&OS=PD/20140710&RS=PD/20140710

Keywords for this news article include: Biotechnology Companies, Legal Issues, Mott Corporation.

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Source: Life Science Weekly


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