Hard anodic coating provides a smooth wear resistant value seating surface on a cast aluminum alloy valve body. Vacuum impregnation with a thermosetting monomer, diallyl phthalate, seals the pores on the coating to prevent galvanic corrosion

Olmore, A. B.

English

NASA Technical Reports Server

July 1966	 Brief 66-10322 
NASA TECH BRIEF 
NASA Tech Briefs are issued to summarize specific innovations derived from the U. S. space 
program and to encourage their commercial application. Copies are available to the public from 
the Clearinghouse for Federal Scientific and Technical Information, Springfield, Virginia 22151. 
Valve Seat Pores Sealed with Thermosetting Monomer 
The problem: 
To provide a hard, wear and corrosion resistant 
valve seating surface on a cast aluminum alloy valve 
body. The fine finish required on the valve seat is 
susceptible to handling damage as well as to damage 
from foreign particles during operation. Corrosion 
products form on the critical seating surface of the 
casting after extended exposure to high humidity at 
elevated temperatures. These corrosion products inter-
fere with proper seating of the valve element and 
cause leakage. 
The solution: 
A hard anodic coating provides a smooth wear re-
sistant surface. Vacuum impregnation with a thermo-
setting monomer, diallyl phthalate, seals the pores on 
the anodic coating to prevent galvanic corrosion. 
How it's done: 
The seat area is machined and lapped to the proper 
configuration and finish. A hard anodized coating 
approximately 0.002-inch thick is applied to the seat 
area itself as well as to surfaces immediately adjacent 
to the seat. To apply the impregnating monomer, the 
part first is exposed to a maximum absolute pressure 
of one millimeter of mercury. This effectively removes 
any moisture and entrapped gases that may exist in 
the pores of the anodized coating. The impregnating
solution then is forced into the pores under a pressure 
of 100 psi at approximately 200° F. The surface is 
then washed lightly in a suitable solvent to remove 
excess material. A final curing process. at approxi-
mately 285° F sets the resin. 
Notes: 
I. A final lapping process to remove the slight film of 
resin is usually required for good seat leakage 
characteristics.. Removal of this thin film does not 
impair corrosion resistance since the pores remain 
impregnated. 
2. Inquiries concerning this invention may be di-
rected to: 
Technology Utilization Officer 
Marshall Space Flight Center 
Huntsville, Alabama, 35812 
Reference: B66-10322 
Patent status: 
Inquiries about obtaining rights for the commercial 
use of this invention may be made to NASA, Code 
GP, Washington, D.C. 20546. 
Source: Arthur B. Olmore

of North American Aviation, Inc.

under contract to

Marshall Space Flight Center

(M-FS-900) 
Category 03 
This document was prepared under the sponsorship of the National 
Aeronautics and Space Administration. Neither the United States 
Government nor any person acting on behalf of the United States
Government assumes any liability resulting from the use of the 
information contained in this document, or warrants that such use 
will be free from privately owned rights.
https://ntrs.nasa.gov/search.jsp?R=19660000321 2020-03-11T17:40:27+00:00Z


Valve seat pores sealed with thermosetting monomer

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