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U.S. Department of Energy
Office of Scientific and Technical Information

Materials coatings for valves. Quarterly report, January 1-March 31, 1982

Technical Report ·
OSTI ID:6694430

This quarterly report, for the period January 1-March 31, 1982, summarizes activities in the development of erosion resistant coatings for the wear-prone components of letdown and control valves used in coal liquefaction plants. These activities have followed a course of (1) material and process development of CVD (chemically vapor deposited) TiB/sub 2/ (titanium diboride) coatings; (2) erosion testing and screening of coated cermet substrates; and (3) prototype trim fabrication with associted development of fixturing and assembly hardware. Additional cemented carbide substrate materials (Kennametal K801 and K151A) were evaluated along with K701 and K703. Only the K701/TiB/sub 2/ combination has proven to be sufficiently reliable to warrant field testing in a process plant environment, and then only if the substrate has been precoated with electroplated nickel to promote adhesion between coating and carbide substrate and reduce thermophysical stresses. A cleaning and plating process has been developed to produce nickel precoats stable at the temperatures of CVD. TiB/sub 2/ coated specimens have been subjected to simulated slurry erosion testing at Battelle Columbus Labs (BCL) with some materials such as K701/TiB/sub 2/ and hot pressed (HP) TiB/sub 2//TiB/sub 2/ exhibiting very low erosion rates. Prototypes of the letdown valve plugs for the EDS and SRC-I processes have been fabricated and coated. Preliminary metallographic evaluation of the prototype plugs and descriptions of CVD furnace hardware are presented.

Research Organization:
Sandia National Labs., Albuquerque, NM (USA)
DOE Contract Number:
AC04-76DP00789
OSTI ID:
6694430
Report Number(s):
SAND-82-2137; ON: DE83003629
Country of Publication:
United States
Language:
English