Precipitation hardening of tantalum coated metals

Patent metadata

Field	Value
Publication number	US-9963757-B2
Application number	US-201415026261-A
Country	US
Kind code	B2
Filing date	Nov 19, 2014
Priority date	Dec 2, 2013
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A process includes: (a) providing a tantalum-coated metal alloy substrate; (b) heat annealing the tantalum-coated metal alloy substrate by heating to an annealing temperature for the tantalum-coated metal alloy substrate, holding at the annealing temperature for a period of time and then quenching to a temperature below 50 degrees Celsius; (c) heating the tantalum-coated metal substrate to the precipitation hardening temperature of the metal alloy substrate; and (d) cooling the tantalum-coated metal alloy substrate to a temperature below 50 degrees Celsius; wherein the process is further characterized by carrying out steps (b)-(d) under a tantalum-inert gas atmosphere and by quenching in step (b) and cooling in step (d) being carried out by flowing a tantalum-inert gas having a temperature of less than 50 degrees Celsius over the tantalum-coated metal alloy substrate.

First claim

The invention claimed is:

1. A process comprising:
(a) providing a tantalum-coated metal alloy substrate prepared by providing a precipitation hardened metal alloy substrate and applying tantalum to the substrate while sustaining a temperature greater than 700 degrees Celsius, characterized by resulting in a homogeneous tantalum coating over the metal alloy substrate;
(b) heat annealing the tantalum-coated metal alloy substrate by heating to an annealing temperature for the tantalum-coated metal alloy substrate, holding at the annealing temperature for a period of time and then quenching to a temperature below 50 degrees Celsius;
(c) heating the tantalum-coated metal substrate to the precipitation hardening temperature of the metal alloy substrate; and
(d) cooling the tantalum-coated metal alloy substrate to a temperature below 50 degrees Celsius;

wherein the process is further characterized by carrying out steps (b)-(d) under a tantalum-inert gas atmosphere and by quenching in step (b) and cooling in step (d) being carried out by flowing a tantalum-inert gas having a temperature of less than 50 degrees Celsius over the tantalum-coated metal alloy substrate.

2. The process of claim 1 , further characterized by the tantalum-inert gas comprising a noble gas.

3. The process of claim 1 , further characterize by the tantalum-inert gas comprising at least 99.999 mole-percent argon based on total tantalum-inert gas composition.

4. The process of claim 1 , further characterized by the metal alloy substrate that is tantalum-coated being a stainless steel.

5. The process of claim 1 , further characterized by step (d) causing the tantalum-coated metal alloy substrate to cool from the precipitation hardening temperature to a temperature below 50 degrees Celsius at a rate of 100 degrees Celsius per hour or faster and 200° C. per hour or slower.

Assignees

• Dow Global Technologies Llc

Inventors

• Woodcraft Valentina A
• Liening Eugene L

Classifications

• C21D1/74

  Methods of treatment in inert gas, controlled atmosphere, vacuum or pulverulent material · CPC title

• C22F1/18

  High-melting or refractory metals or alloys based thereon · CPC title

• C21D1/613

  Gases; Liquefied or solidified normally gaseous material · CPC title

• C21D1/26

  Methods of annealing · CPC title

• C21D6/04

  Hardening by cooling below 0 degrees Celsius · CPC title