Browse Prior Art Database

Method of Hardening Metal or Ceramic Objects

IP.com Disclosure Number: IPCOM000038150D
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Avouris, P: AUTHOR [+3]

Abstract

Disclosed is a method of hardening of tool bits, of artificial hip joints, of metal screens for the printing industry, etc.

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 78% of the total text.

Page 1 of 1

Method of Hardening Metal or Ceramic Objects

Disclosed is a method of hardening of tool bits, of artificial hip joints, of metal screens for the printing industry, etc.

Chemical vapor deposition (CVD) or plasma CVD can be used to deposit hard coatings on objects in the deposition chamber. In normal CVD, the part is heated to high temperature (500oC for deposition of tungsten carbide), while in plasma CVD, the molecules of the gas are broken apart by electron bombardment rather than by thermal processes on the surface of the part to be coated. In both cases, however, the material deposits on every hot surface, or all surfaces in contact with the plasma. When the material on the chamber walls reaches a certain thickness, it generally flakes off and contaminates the part being coated.

We disclose a method to lay down a hard coating on a conducting surface by electron bombardment of the surface which is immersed in a very low pressure of a gas which contributes the atoms of interest to the coating. Since the electron beam is much less costly to produce than an ion beam of a few hundred keV, the process will be much cheaper. Since the material coats out only on surfaces bombarded by electrons, the deposition chamber remains clean and will not contaminate parts to be coated.

We use the fact that a clean surface of silicon is very reactive, so that Si2H6 or NH3 will react immediately to make a monolayer of silicon or silicon nitride. The reaction then stops, since the s...