Background of invention:

The indigenous Co bait-Chromium Carbide wear resistant coating process has been established for aero engine parts viz. Ring Locating, Case Diffuser, Outer Combustion Assembly etc. after extensive trials in Laboratory.

This invention relates to an indigenous method and set-up of the equipment to immerse the full part into cobalt-chromium carbide coating solution without agitation. Agitation shall be started after 30 seconds. Though, at the beginning .cobalt-chromium carbide coating on part was carried out by partial immersion and rotating technique, for the want of finalizing of dip tank design / fabrication. This set-up is changed completely by dipping the part in a big coating tank. In this invention the coating tank, Anode and fixture are used to facilitate full immersion of the part and agitation of the bath by mechanical means. This modification has succeeded in making the cobalt-chromium carbide coating on some hot end components of jet engines for imparting dry wear resistance and metallurgical properties.

Summary of invention:

The indigenous method introduced comprises of the following features:

The technology involves immerse the full part into cobalt-chromium carbide coating solution without agitation. Agitation shall be started after 30 seconds. Initially the coating of the parts was accomplished in a small tank; and cobalt-chromium carbide coating by partial immersion and rotating technique. Later a big tank was set-up. Anode and fixture are used to facilitate full immersion of the part and agitation of the bath by mechanical means. It is found that in the modified process the coating thickness and distribution of carbides with-in the coating is much uniform. This modification has culminated in simpler manufacturing process with improved metallurgical properties.

Objective of Invention:

1. Main objective is developing an indigenized coating method and equipment set-up so as to make the coating process simpler.

2. Foreign Exchange Savings to the country

3. Reduction in supply lead time for coating

Detailed description of the invention:

Cobalt- chromium carbide coating process has been applied to a few parts. Due to the bigger size of the component, there is a constraint to carry out the coating process in the small tank. Hence, a few modifications have been carried out in the fixture and part rotating arrangement is made. The required coating was achieved by partial immersion and rotating technique, for the want of finalizing the dip tank design/ fabrication.

Finally a regular, production tank was set-up. Anode and fixture are used to facilitate full immersion of the part and agitation of the bath by mechanical means. It is found that in the modified process the coating thickness and distribution of carbides with-in the coating is much uniform. This modification has culminated in simpler manufacturing process and achieved required coating with improved metallurgical properties.

Analysis carried-out:

The characteristics of the coating are evaluated based on metallographic examination carried on a dummy part. During establishment of the coating process, coating parameters were optimized. Coating is carried out with designed anode which is located concentrically around the part.

Claims:

We claim

1 An indigenously developed method to improve metallurgical properties of the Coating.

2 The method and equipment set-up claimed in claim 1 has resulted in coating of the parts much simpler.