A copper base insert coated with a layer of aluminum oxide ceramic prevents frictional binding between the gate and base surfaces of a gate valve which are subject to rapid sliding action and high temperatures

Brass, A.

English

NASA Technical Reports Server

sin Layer of Aluminum Oxide Ceramic 
Base Insert (Copper) 
Gate (Copper 
July 1964	 Brief 63-10562 
.
	
NASA TECH BRIEF 
This NASA Tech Brief is issued by the Technology Utilization Division to acquaint 
industry with the technical content of an innovation derived from the space program. 
Gate Valve With Ceramic-Coated Base Operates at High Temperatures 
t
The problem: To prevent frictional binding or 
welding between the gate and base surfaces of a gate 
valve that are subject to very rapid sliding action (ap-
proximately 5-millisecond duration) relative to one 
another in a high-temperature environment of 4,000° 
to 5,000° F. Conventional gate valves, which incor-
porate metal (e.g., brass, copper, stainless steel) gates 
and bases, require replacement after each closure. 
The solution: A renewable base insert of copper 
coated with a thin layer of aluminum oxide ceramic 
on the surface that comes into contact with the gate. 
How it's done: The base insert is coated by spray-
ing with a preparation of alumina (activated, pow-
dered, catalyst grade AL-0102 P-98 percent Al203) 
to a depth of approximately 0.008 inch. The coating is 
then ground down to 0.005 inch. This insert is posi-
tioned with the aluminum oxide surface facing the 
surface of a copper gate in the valve.
The thin film of aluminum oxide ceramic has a neg-
ligible effect on the heat-sink characteristics of the 
copper base and gate and prevents welding of the sur-
faces during sliding action in several 5-millisecond 
closures of the valve at air temperatures of 4,000° to 
5,000° F. The thin ceramic coating is highly resistant 
to cracking and chipping and requires replacement 
only after it has deteriorated as the result of ablation. 
To replace the coating, the base insert is removed from 
the valve and resurfaced with aluminum oxide after 
grinding away the wornout surface. 
Notes: 
1. This coating can be advantageously applied to any 
metal surfaces which come into intimate sliding 
contact in high-temperature environments. 
-	 (continued overleaf) 
This document was prepared under the sponsorship of the National 	 this document, or that the use of any information, apparatus, method, 
Aeronautics and Space Administration. Neither the United States Govern,	 or process disclosed in this document may not infringe privately-owned 
ment, nor NASA, nor any person acting on behalf of NASA: A. Makes	 rights; or B. Assumes any liabilities with respect to the use of, or for 
any warranty or representation, express or implied, with respect to the	 damages resulting from the use of, any information, apparatus, method, 
accuracy, completeness, or usefulness of the information contained in	 or process disclosed in this document.
https://ntrs.nasa.gov/search.jsp?R=19630000111 2020-03-11T16:48:18+00:00Z
2. For further information about this invention in-
quiries may be directed to: 
Technology Utilization Officer 
Ames Research Center 
Moffett Field, California, 94035 
Reference: B63-10562
Patent status: NASA encourages the immediate 
commercial use of this invention. Inquiries about ob-
taining rights for its commercial use may be made to 
NASA Headquarters, Washington, D.C., 20546. 
Source: Abraham Brass 
(ARC-23) 
Brief 63-10562


Gate value with ceramic-coated base operates at high temperatures

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