Scott O

1
Introduction

• Plasma Processes, Inc. is a small business that
  specializes in the development and fabrication of
  refractory metals and advanced ceramic materials
  for High Heat Flux (HHF) applications.
• Innovative Vacuum Plasma Spray (VPS) forming
  techniques are used to produced complex
  configurations.
• As a result of recent advancements, engineered
  tungsten surfaces for IFE dry chamber walls that
  eliminate helium build-up are a possibility.

2
Examples of VPS Formed Tungsten Components

• Plasma facing component heat sinks with in-situ
  formed helical fins
• Thin-walled closed end cartridges for processing
  samples in microgravity (leak rate of lt1x10-8
  sccs He)
• Nozzle inserts to reduce/eliminate throat erosion
  solid rocket engines.

3
Micrographs of VPS Tungsten Deposits Using Micron
Size Starting Powders
B
C
A
Average starting particle size A) 26mm B)
13mm C) 3mm Micrographs demonstrate by
reducing the starting powder size the grain
structure of the resulting deposit can be reduced.
4
Nanostructured Materials Development

• To date, nanostructured alumina components have
  been fabricated.
• Bright field TEM images of plasma sprayed alumina
  (A) alumina grains lt100nm size and (B) lattice
  fringes indicating 20nm subdomains within the
  nanosize particles.

A
B
5
Nanostructured Tungsten Development

• PPI is currently developing innovative techniques
  for producing nanostructured tungsten components
  using nanosized tungsten and hafnium carbide
  starting powders.
• The goal of this effort is to evaluate the affect
  ultrafine grains will have on the mechanical and
  physical properties of tungsten.
• To prevent coarsening of the nanosized tungsten
  during fabrication and subsequent high
  temperature usage, hafnium carbide is being added
  to pin the tungsten grain boundaries.
• Fabrication of samples for analysis is expected
  before the end of 2002.