Protective cladding for a molybdenum substrate

• US 4,977,001 A
• Filed: 01/20/1988
• Issued: 12/11/1990
• Est. Priority Date: 08/01/1986
• Status: Expired due to Fees

• Current Assignee: Vesuvius Crucible Company (Vesuvius Plc)
• Original Assignee: Vesuvius Crucible Company (Vesuvius Plc)
• Inventors: Greenspan, David C.
• Primary Examiner(s): HERBERT JR, THOMAS
• Application Number:
  US07/145,947
• Time in Patent Office: 1,056 Days
• Field of Search: 374/139, 374/140, 374/208, 136/234, 428/469, 428/251, 428/701, 428/34.6, 501/68, 501/121
• US Class Current: 428/34.6
• CPC Class Codes: G01K 1/105 for siderurgical use
• CPC Class Codes: G01K 1/16 Special arrangements for conducting heat from the object to the sensitive element
• CPC Class Codes: Y10T 428/1317 Multilayer [continuous layer]

Abstract

A cladding for a molybdenum body such as a molybdenum tube for protecting the molybdenum from corrosive high temperature environments. The cladding contains oxides of molybdenum, aluminum, silicon and alkali metals in about the following percentages by weight of the total metal content: molybdenum 18-40 percent; aluminum 10-25 percent; silicon 25-50 percent; and, alkali metals 8-12 percent. The cladding may be formed by bringing the molybdenum body into contact in the presence of oxygen, with a refractory containing oxides of aluminum, silicon and alkali metals at a temperature greater than 400° C.

Claims

1. A corrosion-resistant article comprising a molybdenum substrate having a reaction formed clad layer of a substantially amorphous composition comprising oxide-containing compounds of the elements molybdenum, aluminum, silicon and at least one alkali metal, said composition comprising said elements in about the following percentages by weight of the total metal content:

space="preserve" listing-type="tabular">______________________________________ molybdenum 18-40 aluminum 10-25 silicon 25-50 alkali metal(s) 8-12. ______________________________________

2. A corrosion-resistant article in accordance with claim 1 wherein said molybdenum substrate is an elongated, closed end tube.

3. A corrosion-resistant article in accordance with claim 1 wherein said amorphous composition comprises about 35-40 weight percent molybdenum, about 10-15 weight percent aluminum, and about 25-30 weight percent silicon.

4. A corrosion-resistant article in accordance with claim 1 wherein said amorphous composition contains other metals in a concentration of about 10-12 percent by weight of the total metal content.

5. A corrosion-resistant article in accordance with claim 1 wherein said alkali metals comprise about 3-5 percent by weight sodium and about 5-7 percent by weight potassium.

6. A corrosion-resistant article in accordance with claim 1 wherein said amorphous composition comprises:

space="preserve" listing-type="tabular">______________________________________ Element Percent by Weight ______________________________________ molybdenum 39-40 aluminum 10-12 silicon 25-30 sodium 3-4 potassium 5-6. ______________________________________